1 | /* Copyright (c) 2000, 2013, Oracle and/or its affiliates. |
2 | Copyright (c) 2010, 2017, MariaDB Corporation |
3 | |
4 | This program is free software; you can redistribute it and/or modify |
5 | it under the terms of the GNU General Public License as published by |
6 | the Free Software Foundation; version 2 of the License. |
7 | |
8 | This program is distributed in the hope that it will be useful, |
9 | but WITHOUT ANY WARRANTY; without even the implied warranty of |
10 | MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
11 | GNU General Public License for more details. |
12 | |
13 | You should have received a copy of the GNU General Public License |
14 | along with this program; if not, write to the Free Software Foundation, |
15 | 51 Franklin Street, Suite 500, Boston, MA 02110-1335 USA */ |
16 | |
17 | /* |
18 | Description of the query cache: |
19 | |
20 | 1. Query_cache object consists of |
21 | - query cache memory pool (cache) |
22 | - queries hash (queries) |
23 | - tables hash (tables) |
24 | - list of blocks ordered as they allocated in memory |
25 | (first_block) |
26 | - list of queries block (queries_blocks) |
27 | - list of used tables (tables_blocks) |
28 | |
29 | 2. Query cache memory pool (cache) consists of |
30 | - table of steps of memory bins allocation |
31 | - table of free memory bins |
32 | - blocks of memory |
33 | |
34 | 3. Memory blocks |
35 | |
36 | Every memory block has the following structure: |
37 | |
38 | +----------------------------------------------------------+ |
39 | | Block header (Query_cache_block structure) | |
40 | +----------------------------------------------------------+ |
41 | |Table of database table lists (used for queries & tables) | |
42 | +----------------------------------------------------------+ |
43 | | Type depended header | |
44 | |(Query_cache_query, Query_cache_table, Query_cache_result)| |
45 | +----------------------------------------------------------+ |
46 | | Data ... | |
47 | +----------------------------------------------------------+ |
48 | |
49 | Block header consists of: |
50 | - type: |
51 | FREE Free memory block |
52 | QUERY Query block |
53 | RESULT Ready to send result |
54 | RES_CONT Result's continuation |
55 | RES_BEG First block of results, that is not yet complete, |
56 | written to cache |
57 | RES_INCOMPLETE Allocated for results data block |
58 | TABLE Block with database table description |
59 | INCOMPLETE The destroyed block |
60 | - length of block (length) |
61 | - length of data & headers (used) |
62 | - physical list links (pnext/pprev) - used for the list of |
63 | blocks ordered as they are allocated in physical memory |
64 | - logical list links (next/prev) - used for queries block list, tables block |
65 | list, free memory block lists and list of results block in query |
66 | - number of elements in table of database table list (n_tables) |
67 | |
68 | 4. Query & results blocks |
69 | |
70 | Query stored in cache consists of following blocks: |
71 | |
72 | more more |
73 | recent+-------------+ old |
74 | <-----|Query block 1|------> double linked list of queries block |
75 | prev | | next |
76 | +-------------+ |
77 | <-| table 0 |-> (see "Table of database table lists" description) |
78 | <-| table 1 |-> |
79 | | ... | +--------------------------+ |
80 | +-------------+ +-------------------------+ | |
81 | NET | | | V V | |
82 | struct| | +-+------------+ +------------+ | |
83 | <-----|query header |----->|Result block|-->|Result block|-+ doublelinked |
84 | writer| |result| |<--| | list of results |
85 | +-------------+ +------------+ +------------+ |
86 | |charset | +------------+ +------------+ no table of dbtables |
87 | |encoding + | | result | | result | |
88 | |query text |<-----| header | | header |------+ |
89 | +-------------+parent| | | |parent| |
90 | ^ +------------+ +------------+ | |
91 | | |result data | |result data | | |
92 | | +------------+ +------------+ | |
93 | +---------------------------------------------------+ |
94 | |
95 | First query is registered. During the registration query block is |
96 | allocated. This query block is included in query hash and is linked |
97 | with appropriate database tables lists (if there is no appropriate |
98 | list exists it will be created). |
99 | |
100 | Later when query has performed results is written into the result blocks. |
101 | A result block cannot be smaller then QUERY_CACHE_MIN_RESULT_DATA_SIZE. |
102 | |
103 | When new result is written to cache it is appended to the last result |
104 | block, if no more free space left in the last block, new block is |
105 | allocated. |
106 | |
107 | 5. Table of database table lists. |
108 | |
109 | For quick invalidation of queries all query are linked in lists on used |
110 | database tables basis (when table will be changed (insert/delete/...) |
111 | this queries will be removed from cache). |
112 | |
113 | Root of such list is table block: |
114 | |
115 | +------------+ list of used tables (used while invalidation of |
116 | <----| Table |-----> whole database) |
117 | prev| block |next +-----------+ |
118 | | | +-----------+ |Query block| |
119 | | | |Query block| +-----------+ |
120 | +------------+ +-----------+ | ... | |
121 | +->| table 0 |------>|table 0 |----->| table N |---+ |
122 | |+-| |<------| |<-----| |<-+| |
123 | || +------------+ | ... | | ... | || |
124 | || |table header| +-----------+ +-----------+ || |
125 | || +------------+ | ... | | ... | || |
126 | || |db name + | +-----------+ +-----------+ || |
127 | || |table name | || |
128 | || +------------+ || |
129 | |+--------------------------------------------------------+| |
130 | +----------------------------------------------------------+ |
131 | |
132 | Table block is included into the tables hash (tables). |
133 | |
134 | 6. Free blocks, free blocks bins & steps of freeblock bins. |
135 | |
136 | When we just started only one free memory block existed. All query |
137 | cache memory (that will be used for block allocation) were |
138 | containing in this block. |
139 | When a new block is allocated we find most suitable memory block |
140 | (minimal of >= required size). If such a block can not be found, we try |
141 | to find max block < required size (if we allocate block for results). |
142 | If there is no free memory, oldest query is removed from cache, and then |
143 | we try to allocate memory. Last step should be repeated until we find |
144 | suitable block or until there is no unlocked query found. |
145 | |
146 | If the block is found and its length more then we need, it should be |
147 | split into 2 blocks. |
148 | New blocks cannot be smaller then min_allocation_unit_bytes. |
149 | |
150 | When a block becomes free, its neighbor-blocks should be tested and if |
151 | there are free blocks among them, they should be joined into one block. |
152 | |
153 | Free memory blocks are stored in bins according to their sizes. |
154 | The bins are stored in size-descending order. |
155 | These bins are distributed (by size) approximately logarithmically. |
156 | |
157 | First bin (number 0) stores free blocks with |
158 | size <= query_cache_size>>QUERY_CACHE_MEM_BIN_FIRST_STEP_PWR2. |
159 | It is first (number 0) step. |
160 | On the next step distributed (1 + QUERY_CACHE_MEM_BIN_PARTS_INC) * |
161 | QUERY_CACHE_MEM_BIN_PARTS_MUL bins. This bins allocated in interval from |
162 | query_cache_size>>QUERY_CACHE_MEM_BIN_FIRST_STEP_PWR2 to |
163 | query_cache_size>>QUERY_CACHE_MEM_BIN_FIRST_STEP_PWR2 >> |
164 | QUERY_CACHE_MEM_BIN_STEP_PWR2 |
165 | ... |
166 | On each step interval decreases in 2 power of |
167 | QUERY_CACHE_MEM_BIN_STEP_PWR2 |
168 | times, number of bins (that distributed on this step) increases. If on |
169 | the previous step there were N bins distributed , on the current there |
170 | would be distributed |
171 | (N + QUERY_CACHE_MEM_BIN_PARTS_INC) * QUERY_CACHE_MEM_BIN_PARTS_MUL |
172 | bins. |
173 | Last distributed bin stores blocks with size near min_allocation_unit |
174 | bytes. |
175 | |
176 | For example: |
177 | query_cache_size>>QUERY_CACHE_MEM_BIN_FIRST_STEP_PWR2 = 100, |
178 | min_allocation_unit = 17, |
179 | QUERY_CACHE_MEM_BIN_STEP_PWR2 = 1, |
180 | QUERY_CACHE_MEM_BIN_PARTS_INC = 1, |
181 | QUERY_CACHE_MEM_BIN_PARTS_MUL = 1 |
182 | (in followed picture showed right (low) bound of bin): |
183 | |
184 | | 100>>1 50>>1 |25>>1| |
185 | | | | | | | |
186 | | 100 75 50 41 33 25 21 18 15| 12 | - bins right (low) bounds |
187 | |
188 | |\---/\-----/\--------/\--------|---/ | |
189 | | 0 1 2 3 | | - steps |
190 | \-----------------------------/ \---/ |
191 | bins that we store in cache this bin showed for example only |
192 | |
193 | |
194 | Calculation of steps/bins distribution is performed only when query cache |
195 | is resized. |
196 | |
197 | When we need to find appropriate bin, first we should find appropriate |
198 | step, then we should calculate number of bins that are using data |
199 | stored in Query_cache_memory_bin_step structure. |
200 | |
201 | Free memory blocks are sorted in bins in lists with size-ascending order |
202 | (more small blocks needed frequently then bigger one). |
203 | |
204 | 7. Packing cache. |
205 | |
206 | Query cache packing is divided into two operation: |
207 | - pack_cache |
208 | - join_results |
209 | |
210 | pack_cache moved all blocks to "top" of cache and create one block of free |
211 | space at the "bottom": |
212 | |
213 | before pack_cache after pack_cache |
214 | +-------------+ +-------------+ |
215 | | query 1 | | query 1 | |
216 | +-------------+ +-------------+ |
217 | | table 1 | | table 1 | |
218 | +-------------+ +-------------+ |
219 | | results 1.1 | | results 1.1 | |
220 | +-------------+ +-------------+ |
221 | | free | | query 2 | |
222 | +-------------+ +-------------+ |
223 | | query 2 | | table 2 | |
224 | +-------------+ ---> +-------------+ |
225 | | table 2 | | results 1.2 | |
226 | +-------------+ +-------------+ |
227 | | results 1.2 | | results 2 | |
228 | +-------------+ +-------------+ |
229 | | free | | free | |
230 | +-------------+ | | |
231 | | results 2 | | | |
232 | +-------------+ | | |
233 | | free | | | |
234 | +-------------+ +-------------+ |
235 | |
236 | pack_cache scan blocks in physical address order and move every non-free |
237 | block "higher". |
238 | |
239 | pack_cach remove every free block it finds. The length of the deleted block |
240 | is accumulated to the "gap". All non free blocks should be shifted with the |
241 | "gap" step. |
242 | |
243 | join_results scans all complete queries. If the results of query are not |
244 | stored in the same block, join_results tries to move results so, that they |
245 | are stored in one block. |
246 | |
247 | before join_results after join_results |
248 | +-------------+ +-------------+ |
249 | | query 1 | | query 1 | |
250 | +-------------+ +-------------+ |
251 | | table 1 | | table 1 | |
252 | +-------------+ +-------------+ |
253 | | results 1.1 | | free | |
254 | +-------------+ +-------------+ |
255 | | query 2 | | query 2 | |
256 | +-------------+ +-------------+ |
257 | | table 2 | | table 2 | |
258 | +-------------+ ---> +-------------+ |
259 | | results 1.2 | | free | |
260 | +-------------+ +-------------+ |
261 | | results 2 | | results 2 | |
262 | +-------------+ +-------------+ |
263 | | free | | results 1 | |
264 | | | | | |
265 | | | +-------------+ |
266 | | | | free | |
267 | | | | | |
268 | +-------------+ +-------------+ |
269 | |
270 | If join_results allocated new block(s) then we need call pack_cache again. |
271 | |
272 | 7. Interface |
273 | The query cache interfaces with the rest of the server code through 7 |
274 | functions: |
275 | 1. Query_cache::send_result_to_client |
276 | - Called before parsing and used to match a statement with the stored |
277 | queries hash. |
278 | If a match is found the cached result set is sent through repeated |
279 | calls to net_real_write. (note: calling thread doesn't have a regis- |
280 | tered result set writer: thd->net.query_cache_query=0) |
281 | 2. Query_cache::store_query |
282 | - Called just before handle_select() and is used to register a result |
283 | set writer to the statement currently being processed |
284 | (thd->net.query_cache_query). |
285 | 3. query_cache_insert |
286 | - Called from net_real_write to append a result set to a cached query |
287 | if (and only if) this query has a registered result set writer |
288 | (thd->net.query_cache_query). |
289 | 4. Query_cache::invalidate |
290 | Query_cache::invalidate_locked_for_write |
291 | - Called from various places to invalidate query cache based on data- |
292 | base, table and myisam file name. During an on going invalidation |
293 | the query cache is temporarily disabled. |
294 | 5. Query_cache::flush |
295 | - Used when a RESET QUERY CACHE is issued. This clears the entire |
296 | cache block by block. |
297 | 6. Query_cache::resize |
298 | - Used to change the available memory used by the query cache. This |
299 | will also invalidate the entrie query cache in one free operation. |
300 | 7. Query_cache::pack |
301 | - Used when a FLUSH QUERY CACHE is issued. This changes the order of |
302 | the used memory blocks in physical memory order and move all avail- |
303 | able memory to the 'bottom' of the memory. |
304 | |
305 | |
306 | TODO list: |
307 | |
308 | - Delayed till after-parsing qache answer (for column rights processing) |
309 | - Optimize cache resizing |
310 | - if new_size < old_size then pack & shrink |
311 | - if new_size > old_size copy cached query to new cache |
312 | - Move MRG_MYISAM table type processing to handlers, something like: |
313 | tables_used->table->file->register_used_filenames(callback, |
314 | first_argument); |
315 | - QC improvement suggested by Monty: |
316 | - Add a counter in open_table() for how many MERGE (ISAM or MyISAM) |
317 | tables are cached in the table cache. |
318 | (This will be trivial when we have the new table cache in place I |
319 | have been working on) |
320 | - After this we can add the following test around the for loop in |
321 | is_cacheable:: |
322 | |
323 | if (thd->temp_tables || global_merge_table_count) |
324 | |
325 | - Another option would be to set thd->lex->safe_to_cache_query to 0 |
326 | in 'get_lock_data' if any of the tables was a tmp table or a |
327 | MRG_ISAM table. |
328 | (This could be done with almost no speed penalty) |
329 | */ |
330 | |
331 | #include "mariadb.h" /* NO_EMBEDDED_ACCESS_CHECKS */ |
332 | #if defined(DBUG_OFF) && defined(HAVE_MADVISE) |
333 | #include <sys/mman.h> |
334 | #endif |
335 | #include "sql_priv.h" |
336 | #include "sql_basic_types.h" |
337 | #include "sql_cache.h" |
338 | #include "sql_parse.h" // check_table_access |
339 | #include "tztime.h" // struct Time_zone |
340 | #include "sql_acl.h" // SELECT_ACL |
341 | #include "sql_base.h" // TMP_TABLE_KEY_EXTRA |
342 | #include "debug_sync.h" // DEBUG_SYNC |
343 | #include "sql_table.h" |
344 | #ifdef HAVE_QUERY_CACHE |
345 | #include <m_ctype.h> |
346 | #include <my_dir.h> |
347 | #include <hash.h> |
348 | #include "../storage/myisammrg/ha_myisammrg.h" |
349 | #include "../storage/myisammrg/myrg_def.h" |
350 | #include "probes_mysql.h" |
351 | #include "transaction.h" |
352 | #include "strfunc.h" |
353 | |
354 | const uchar *query_state_map; |
355 | |
356 | #ifdef EMBEDDED_LIBRARY |
357 | #include "emb_qcache.h" |
358 | #endif |
359 | |
360 | #if defined(EXTRA_DEBUG) && !defined(DBUG_OFF) |
361 | #define RW_WLOCK(M) {DBUG_PRINT("lock", ("rwlock wlock %p",(M))); \ |
362 | if (!mysql_rwlock_wrlock(M)) DBUG_PRINT("lock", ("rwlock wlock ok")); \ |
363 | else DBUG_PRINT("lock", ("rwlock wlock FAILED %d", errno)); } |
364 | #define RW_RLOCK(M) {DBUG_PRINT("lock", ("rwlock rlock %p",(M))); \ |
365 | if (!mysql_rwlock_rdlock(M)) DBUG_PRINT("lock", ("rwlock rlock ok")); \ |
366 | else DBUG_PRINT("lock", ("rwlock wlock FAILED %d", errno)); } |
367 | #define RW_UNLOCK(M) {DBUG_PRINT("lock", ("rwlock unlock %p",(M))); \ |
368 | if (!mysql_rwlock_unlock(M)) DBUG_PRINT("lock", ("rwlock unlock ok")); \ |
369 | else DBUG_PRINT("lock", ("rwlock unlock FAILED %d", errno)); } |
370 | #define BLOCK_LOCK_WR(B) {DBUG_PRINT("lock", ("%d LOCK_WR %p",\ |
371 | __LINE__,(B))); \ |
372 | B->query()->lock_writing();} |
373 | #define BLOCK_LOCK_RD(B) {DBUG_PRINT("lock", ("%d LOCK_RD %p",\ |
374 | __LINE__,(B))); \ |
375 | B->query()->lock_reading();} |
376 | #define BLOCK_UNLOCK_WR(B) { \ |
377 | DBUG_PRINT("lock", ("%d UNLOCK_WR %p",\ |
378 | __LINE__,(B)));B->query()->unlock_writing();} |
379 | #define BLOCK_UNLOCK_RD(B) { \ |
380 | DBUG_PRINT("lock", ("%d UNLOCK_RD %p",\ |
381 | __LINE__,(B)));B->query()->unlock_reading();} |
382 | #define DUMP(C) DBUG_EXECUTE("qcache", {\ |
383 | (C)->cache_dump(); (C)->queries_dump();(C)->tables_dump();}) |
384 | #else |
385 | #define RW_WLOCK(M) mysql_rwlock_wrlock(M) |
386 | #define RW_RLOCK(M) mysql_rwlock_rdlock(M) |
387 | #define RW_UNLOCK(M) mysql_rwlock_unlock(M) |
388 | #define BLOCK_LOCK_WR(B) B->query()->lock_writing() |
389 | #define BLOCK_LOCK_RD(B) B->query()->lock_reading() |
390 | #define BLOCK_UNLOCK_WR(B) B->query()->unlock_writing() |
391 | #define BLOCK_UNLOCK_RD(B) B->query()->unlock_reading() |
392 | #define DUMP(C) |
393 | #endif |
394 | |
395 | |
396 | /** |
397 | Macro that executes the requested action at a synchronization point |
398 | only if the thread has a associated THD session. |
399 | */ |
400 | #if defined(ENABLED_DEBUG_SYNC) |
401 | #define QC_DEBUG_SYNC(name) \ |
402 | do { \ |
403 | THD *thd_tmp= current_thd; \ |
404 | if (thd_tmp) \ |
405 | DEBUG_SYNC(thd_tmp, name); \ |
406 | } while (0) |
407 | #else |
408 | #define QC_DEBUG_SYNC(name) |
409 | #endif |
410 | |
411 | |
412 | /** |
413 | Thread state to be used when the query cache lock needs to be acquired. |
414 | Sets the thread state name in the constructor, resets on destructor. |
415 | */ |
416 | |
417 | struct Query_cache_wait_state |
418 | { |
419 | THD *m_thd; |
420 | PSI_stage_info m_old_stage; |
421 | const char *m_func; |
422 | const char *m_file; |
423 | int m_line; |
424 | |
425 | Query_cache_wait_state(THD *thd, const char *func, |
426 | const char *file, unsigned int line) |
427 | : m_thd(thd), |
428 | m_old_stage(), |
429 | m_func(func), m_file(file), m_line(line) |
430 | { |
431 | if (m_thd) |
432 | set_thd_stage_info(m_thd, |
433 | &stage_waiting_for_query_cache_lock, |
434 | &m_old_stage, |
435 | m_func, m_file, m_line); |
436 | } |
437 | |
438 | ~Query_cache_wait_state() |
439 | { |
440 | if (m_thd) |
441 | set_thd_stage_info(m_thd, &m_old_stage, NULL, m_func, m_file, m_line); |
442 | } |
443 | }; |
444 | |
445 | |
446 | /* |
447 | Check if character is a white space. |
448 | */ |
449 | |
450 | inline bool is_white_space(char c) |
451 | { |
452 | return (query_state_map[(uint) ((uchar) c)] == MY_LEX_SKIP); |
453 | } |
454 | |
455 | |
456 | /** |
457 | Generate a query_string without query comments or duplicated space |
458 | |
459 | @param new_query New query without 'fluff' is stored here |
460 | @param query Original query |
461 | @param query_length Length of original query |
462 | @param additional_length Extra space for query cache we need to allocate |
463 | in new_query buffer. |
464 | |
465 | Note: |
466 | If there is no space to allocate new_query, we will put original query |
467 | into new_query. |
468 | */ |
469 | |
470 | static void make_base_query(String *new_query, |
471 | const char *query, size_t query_length, |
472 | size_t additional_length) |
473 | { |
474 | char *buffer; |
475 | const char *query_end, *last_space; |
476 | |
477 | /* The following is guaranteed by the query_cache interface */ |
478 | DBUG_ASSERT(query[query_length] == 0); |
479 | DBUG_ASSERT(!is_white_space(query[0])); |
480 | /* We do not support UCS2, UTF16, UTF32 as a client character set */ |
481 | DBUG_ASSERT(current_thd->variables.character_set_client->mbminlen == 1); |
482 | |
483 | new_query->length(0); // Don't copy anything from old buffer |
484 | if (new_query->realloc(query_length + additional_length)) |
485 | { |
486 | /* |
487 | We could not allocate the query. Use original query for |
488 | the query cache; Better than nothing.... |
489 | */ |
490 | new_query->set(query, query_length, system_charset_info); |
491 | return; |
492 | } |
493 | |
494 | buffer= (char*) new_query->ptr(); // Store base query here |
495 | query_end= query + query_length; |
496 | last_space= 0; // No space found yet |
497 | |
498 | while (query < query_end) |
499 | { |
500 | char current = *(query++); |
501 | switch (current) { |
502 | case '\'': |
503 | case '`': |
504 | case '"': |
505 | *(buffer++)= current; // copy first quote |
506 | while (query < query_end) |
507 | { |
508 | *(buffer++)= *query; |
509 | if (*(query++) == current) // found pair quote |
510 | break; |
511 | } |
512 | continue; // Continue with next symbol |
513 | case '/': // Start of comment ? |
514 | /* |
515 | Comment of format /#!number #/ or /#M!number #/, must be skipped. |
516 | These may include '"' and other comments, but it should |
517 | be safe to parse the content as a normal string. |
518 | */ |
519 | if (query[0] != '*' || query[1] == '!' || |
520 | (query[1] == 'M' && query[2] == '!')) |
521 | break; |
522 | |
523 | query++; // skip "/" |
524 | while (++query < query_end) |
525 | { |
526 | if (query[0] == '*' && query[1] == '/') |
527 | { |
528 | query+= 2; |
529 | goto insert_space; |
530 | } |
531 | } |
532 | continue; // Will end outer loop |
533 | case '-': |
534 | if (*query != '-' || !is_white_space(query[1])) // Not a comment |
535 | break; |
536 | query++; // skip second "-", and go to search of "\n" |
537 | /* fall through */ |
538 | case '#': |
539 | while (query < query_end) |
540 | { |
541 | if (*(query++) == '\n') |
542 | goto insert_space; |
543 | } |
544 | continue; // Will end outer loop |
545 | default: |
546 | if (is_white_space(current)) |
547 | goto insert_space; |
548 | break; |
549 | } |
550 | *(buffer++)= current; |
551 | continue; |
552 | |
553 | insert_space: |
554 | if (buffer != last_space) |
555 | { |
556 | *(buffer++)= ' '; |
557 | last_space= buffer; |
558 | } |
559 | } |
560 | if (buffer == last_space) |
561 | buffer--; // Remove the last space |
562 | *buffer= 0; // End zero after query |
563 | new_query->length((size_t) (buffer - new_query->ptr())); |
564 | |
565 | /* Copy db_length */ |
566 | memcpy(buffer+1, query_end+1, QUERY_CACHE_DB_LENGTH_SIZE); |
567 | } |
568 | |
569 | |
570 | /** |
571 | Check and change local variable if global one is switched |
572 | |
573 | @param thd thread handle |
574 | */ |
575 | |
576 | void inline fix_local_query_cache_mode(THD *thd) |
577 | { |
578 | if (global_system_variables.query_cache_type == 0) |
579 | thd->variables.query_cache_type= 0; |
580 | } |
581 | |
582 | |
583 | /** |
584 | Serialize access to the query cache. |
585 | If the lock cannot be granted the thread hangs in a conditional wait which |
586 | is signalled on each unlock. |
587 | |
588 | The lock attempt will also fail without wait if lock_and_suspend() is in |
589 | effect by another thread. This enables a quick path in execution to skip waits |
590 | when the outcome is known. |
591 | |
592 | @param mode TIMEOUT the lock can abort because of a timeout |
593 | TRY the lock can abort because it is locked now |
594 | WAIT wait for lock (default) |
595 | |
596 | @note mode is optional and default value is WAIT. |
597 | |
598 | @return |
599 | @retval FALSE An exclusive lock was taken |
600 | @retval TRUE The locking attempt failed |
601 | */ |
602 | |
603 | bool Query_cache::try_lock(THD *thd, Cache_try_lock_mode mode) |
604 | { |
605 | bool interrupt= TRUE; |
606 | Query_cache_wait_state wait_state(thd, __func__, __FILE__, __LINE__); |
607 | DBUG_ENTER("Query_cache::try_lock" ); |
608 | |
609 | mysql_mutex_lock(&structure_guard_mutex); |
610 | DBUG_EXECUTE_IF("status_wait_query_cache_mutex_sleep" , { sleep(5); }); |
611 | if (m_cache_status == DISABLED) |
612 | { |
613 | mysql_mutex_unlock(&structure_guard_mutex); |
614 | DBUG_RETURN(TRUE); |
615 | } |
616 | m_requests_in_progress++; |
617 | fix_local_query_cache_mode(thd); |
618 | |
619 | while (1) |
620 | { |
621 | if (m_cache_lock_status == Query_cache::UNLOCKED) |
622 | { |
623 | m_cache_lock_status= Query_cache::LOCKED; |
624 | #ifndef DBUG_OFF |
625 | m_cache_lock_thread_id= thd->thread_id; |
626 | #endif |
627 | interrupt= FALSE; |
628 | break; |
629 | } |
630 | else if (m_cache_lock_status == Query_cache::LOCKED_NO_WAIT) |
631 | { |
632 | /* |
633 | If query cache is protected by a LOCKED_NO_WAIT lock this thread |
634 | should avoid using the query cache as it is being evicted. |
635 | */ |
636 | break; |
637 | } |
638 | else |
639 | { |
640 | DBUG_ASSERT(m_cache_lock_status == Query_cache::LOCKED); |
641 | /* |
642 | To prevent send_result_to_client() and query_cache_insert() from |
643 | blocking execution for too long a timeout is put on the lock. |
644 | */ |
645 | if (mode == WAIT) |
646 | { |
647 | mysql_cond_wait(&COND_cache_status_changed, &structure_guard_mutex); |
648 | } |
649 | else if (mode == TIMEOUT) |
650 | { |
651 | struct timespec waittime; |
652 | set_timespec_nsec(waittime,50000000UL); /* Wait for 50 msec */ |
653 | int res= mysql_cond_timedwait(&COND_cache_status_changed, |
654 | &structure_guard_mutex, &waittime); |
655 | if (res == ETIMEDOUT) |
656 | break; |
657 | } |
658 | else |
659 | { |
660 | /** |
661 | If we are here, then mode is == TRY and there was someone else using |
662 | the query cache. (m_cache_lock_status != Query_cache::UNLOCKED). |
663 | Signal that we didn't get a lock. |
664 | */ |
665 | DBUG_ASSERT(m_requests_in_progress > 1); |
666 | DBUG_ASSERT(mode == TRY); |
667 | break; |
668 | } |
669 | } |
670 | } |
671 | if (interrupt) |
672 | m_requests_in_progress--; |
673 | mysql_mutex_unlock(&structure_guard_mutex); |
674 | |
675 | DBUG_RETURN(interrupt); |
676 | } |
677 | |
678 | |
679 | /** |
680 | Serialize access to the query cache. |
681 | If the lock cannot be granted the thread hangs in a conditional wait which |
682 | is signalled on each unlock. |
683 | |
684 | This method also suspends the query cache so that other threads attempting to |
685 | lock the cache with try_lock() will fail directly without waiting. |
686 | |
687 | It is used by all methods which flushes or destroys the whole cache. |
688 | */ |
689 | |
690 | void Query_cache::lock_and_suspend(void) |
691 | { |
692 | THD *thd= current_thd; |
693 | Query_cache_wait_state wait_state(thd, __func__, __FILE__, __LINE__); |
694 | DBUG_ENTER("Query_cache::lock_and_suspend" ); |
695 | |
696 | mysql_mutex_lock(&structure_guard_mutex); |
697 | m_requests_in_progress++; |
698 | while (m_cache_lock_status != Query_cache::UNLOCKED) |
699 | mysql_cond_wait(&COND_cache_status_changed, &structure_guard_mutex); |
700 | m_cache_lock_status= Query_cache::LOCKED_NO_WAIT; |
701 | #ifndef DBUG_OFF |
702 | /* Here thd may not be set during shutdown */ |
703 | if (thd) |
704 | m_cache_lock_thread_id= thd->thread_id; |
705 | #endif |
706 | /* Wake up everybody, a whole cache flush is starting! */ |
707 | mysql_cond_broadcast(&COND_cache_status_changed); |
708 | mysql_mutex_unlock(&structure_guard_mutex); |
709 | |
710 | DBUG_VOID_RETURN; |
711 | } |
712 | |
713 | /** |
714 | Serialize access to the query cache. |
715 | If the lock cannot be granted the thread hangs in a conditional wait which |
716 | is signalled on each unlock. |
717 | |
718 | It is used by all methods which invalidates one or more tables. |
719 | */ |
720 | |
721 | void Query_cache::lock(THD *thd) |
722 | { |
723 | Query_cache_wait_state wait_state(thd, __func__, __FILE__, __LINE__); |
724 | DBUG_ENTER("Query_cache::lock" ); |
725 | |
726 | mysql_mutex_lock(&structure_guard_mutex); |
727 | m_requests_in_progress++; |
728 | fix_local_query_cache_mode(thd); |
729 | while (m_cache_lock_status != Query_cache::UNLOCKED) |
730 | mysql_cond_wait(&COND_cache_status_changed, &structure_guard_mutex); |
731 | m_cache_lock_status= Query_cache::LOCKED; |
732 | #ifndef DBUG_OFF |
733 | m_cache_lock_thread_id= thd->thread_id; |
734 | #endif |
735 | mysql_mutex_unlock(&structure_guard_mutex); |
736 | |
737 | DBUG_VOID_RETURN; |
738 | } |
739 | |
740 | |
741 | /** |
742 | Set the query cache to UNLOCKED and signal waiting threads. |
743 | */ |
744 | |
745 | void Query_cache::unlock(void) |
746 | { |
747 | DBUG_ENTER("Query_cache::unlock" ); |
748 | mysql_mutex_lock(&structure_guard_mutex); |
749 | #ifndef DBUG_OFF |
750 | /* Thd may not be set in resize() at mysqld start */ |
751 | THD *thd= current_thd; |
752 | if (thd) |
753 | DBUG_ASSERT(m_cache_lock_thread_id == thd->thread_id); |
754 | #endif |
755 | DBUG_ASSERT(m_cache_lock_status == Query_cache::LOCKED || |
756 | m_cache_lock_status == Query_cache::LOCKED_NO_WAIT); |
757 | m_cache_lock_status= Query_cache::UNLOCKED; |
758 | DBUG_PRINT("Query_cache" ,("Sending signal" )); |
759 | mysql_cond_signal(&COND_cache_status_changed); |
760 | DBUG_ASSERT(m_requests_in_progress > 0); |
761 | m_requests_in_progress--; |
762 | if (m_requests_in_progress == 0 && m_cache_status == DISABLE_REQUEST) |
763 | { |
764 | /* No clients => just free query cache */ |
765 | free_cache(); |
766 | m_cache_status= DISABLED; |
767 | } |
768 | mysql_mutex_unlock(&structure_guard_mutex); |
769 | DBUG_VOID_RETURN; |
770 | } |
771 | |
772 | |
773 | /** |
774 | Helper function for determine if a SELECT statement has a SQL_NO_CACHE |
775 | directive. |
776 | |
777 | @param sql A pointer to the first white space character after SELECT |
778 | |
779 | @return |
780 | @retval TRUE The character string contains SQL_NO_CACHE |
781 | @retval FALSE No directive found. |
782 | */ |
783 | |
784 | static bool has_no_cache_directive(const char *sql) |
785 | { |
786 | while (is_white_space(*sql)) |
787 | sql++; |
788 | |
789 | if (my_toupper(system_charset_info, sql[0]) == 'S' && |
790 | my_toupper(system_charset_info, sql[1]) == 'Q' && |
791 | my_toupper(system_charset_info, sql[2]) == 'L' && |
792 | my_toupper(system_charset_info, sql[3]) == '_' && |
793 | my_toupper(system_charset_info, sql[4]) == 'N' && |
794 | my_toupper(system_charset_info, sql[5]) == 'O' && |
795 | my_toupper(system_charset_info, sql[6]) == '_' && |
796 | my_toupper(system_charset_info, sql[7]) == 'C' && |
797 | my_toupper(system_charset_info, sql[8]) == 'A' && |
798 | my_toupper(system_charset_info, sql[9]) == 'C' && |
799 | my_toupper(system_charset_info, sql[10]) == 'H' && |
800 | my_toupper(system_charset_info, sql[11]) == 'E' && |
801 | my_isspace(system_charset_info, sql[12])) |
802 | return TRUE; |
803 | |
804 | return FALSE; |
805 | } |
806 | |
807 | |
808 | /***************************************************************************** |
809 | Query_cache_block_table method(s) |
810 | *****************************************************************************/ |
811 | |
812 | inline Query_cache_block * Query_cache_block_table::block() |
813 | { |
814 | return (Query_cache_block *)(((uchar*)this) - |
815 | ALIGN_SIZE(sizeof(Query_cache_block_table)*n) - |
816 | ALIGN_SIZE(sizeof(Query_cache_block))); |
817 | } |
818 | |
819 | /***************************************************************************** |
820 | Query_cache_block method(s) |
821 | *****************************************************************************/ |
822 | |
823 | void Query_cache_block::init(size_t block_length) |
824 | { |
825 | DBUG_ENTER("Query_cache_block::init" ); |
826 | DBUG_PRINT("qcache" , ("init block: %p length: %zu" , this, |
827 | block_length)); |
828 | length = block_length; |
829 | used = 0; |
830 | type = Query_cache_block::FREE; |
831 | n_tables = 0; |
832 | DBUG_VOID_RETURN; |
833 | } |
834 | |
835 | void Query_cache_block::destroy() |
836 | { |
837 | DBUG_ENTER("Query_cache_block::destroy" ); |
838 | DBUG_PRINT("qcache" , ("destroy block %p, type %d" , |
839 | this, type)); |
840 | type = INCOMPLETE; |
841 | DBUG_VOID_RETURN; |
842 | } |
843 | |
844 | uint Query_cache_block::() |
845 | { |
846 | return (ALIGN_SIZE(sizeof(Query_cache_block_table)*n_tables) + |
847 | ALIGN_SIZE(sizeof(Query_cache_block))); |
848 | } |
849 | |
850 | uchar* Query_cache_block::data(void) |
851 | { |
852 | return (uchar*)( ((uchar*)this) + headers_len() ); |
853 | } |
854 | |
855 | Query_cache_query * Query_cache_block::query() |
856 | { |
857 | #ifndef DBUG_OFF |
858 | if (type != QUERY) |
859 | query_cache.wreck(__LINE__, "incorrect block type" ); |
860 | #endif |
861 | return (Query_cache_query *) data(); |
862 | } |
863 | |
864 | Query_cache_table * Query_cache_block::table() |
865 | { |
866 | #ifndef DBUG_OFF |
867 | if (type != TABLE) |
868 | query_cache.wreck(__LINE__, "incorrect block type" ); |
869 | #endif |
870 | return (Query_cache_table *) data(); |
871 | } |
872 | |
873 | Query_cache_result * Query_cache_block::result() |
874 | { |
875 | #ifndef DBUG_OFF |
876 | if (type != RESULT && type != RES_CONT && type != RES_BEG && |
877 | type != RES_INCOMPLETE) |
878 | query_cache.wreck(__LINE__, "incorrect block type" ); |
879 | #endif |
880 | return (Query_cache_result *) data(); |
881 | } |
882 | |
883 | Query_cache_block_table * Query_cache_block::table(TABLE_COUNTER_TYPE n) |
884 | { |
885 | return ((Query_cache_block_table *) |
886 | (((uchar*)this)+ALIGN_SIZE(sizeof(Query_cache_block)) + |
887 | n*sizeof(Query_cache_block_table))); |
888 | } |
889 | |
890 | |
891 | /***************************************************************************** |
892 | * Query_cache_table method(s) |
893 | *****************************************************************************/ |
894 | |
895 | extern "C" |
896 | { |
897 | uchar *query_cache_table_get_key(const uchar *record, size_t *length, |
898 | my_bool not_used __attribute__((unused))) |
899 | { |
900 | Query_cache_block* table_block = (Query_cache_block*) record; |
901 | *length = (table_block->used - table_block->headers_len() - |
902 | ALIGN_SIZE(sizeof(Query_cache_table))); |
903 | return (((uchar *) table_block->data()) + |
904 | ALIGN_SIZE(sizeof(Query_cache_table))); |
905 | } |
906 | } |
907 | |
908 | /***************************************************************************** |
909 | Query_cache_query methods |
910 | *****************************************************************************/ |
911 | |
912 | /* |
913 | Following methods work for block read/write locking only in this |
914 | particular case and in interaction with structure_guard_mutex. |
915 | |
916 | Lock for write prevents any other locking. (exclusive use) |
917 | Lock for read prevents only locking for write. |
918 | */ |
919 | |
920 | inline void Query_cache_query::lock_writing() |
921 | { |
922 | RW_WLOCK(&lock); |
923 | } |
924 | |
925 | |
926 | /* |
927 | Needed for finding queries, that we may delete from cache. |
928 | We don't want to wait while block become unlocked. In addition, |
929 | block locking means that query is now used and we don't need to |
930 | remove it. |
931 | */ |
932 | |
933 | bool Query_cache_query::try_lock_writing() |
934 | { |
935 | DBUG_ENTER("Query_cache_block::try_lock_writing" ); |
936 | if (mysql_rwlock_trywrlock(&lock) != 0) |
937 | { |
938 | DBUG_PRINT("info" , ("can't lock rwlock" )); |
939 | DBUG_RETURN(0); |
940 | } |
941 | DBUG_PRINT("info" , ("rwlock %p locked" , &lock)); |
942 | DBUG_RETURN(1); |
943 | } |
944 | |
945 | |
946 | inline void Query_cache_query::lock_reading() |
947 | { |
948 | RW_RLOCK(&lock); |
949 | } |
950 | |
951 | |
952 | inline void Query_cache_query::unlock_writing() |
953 | { |
954 | RW_UNLOCK(&lock); |
955 | } |
956 | |
957 | |
958 | inline void Query_cache_query::unlock_reading() |
959 | { |
960 | RW_UNLOCK(&lock); |
961 | } |
962 | |
963 | |
964 | void Query_cache_query::init_n_lock() |
965 | { |
966 | DBUG_ENTER("Query_cache_query::init_n_lock" ); |
967 | res=0; wri = 0; len = 0; ready= 0; hit_count = 0; |
968 | mysql_rwlock_init(key_rwlock_query_cache_query_lock, &lock); |
969 | lock_writing(); |
970 | DBUG_PRINT("qcache" , ("inited & locked query for block %p" , |
971 | (uchar*) this - |
972 | ALIGN_SIZE(sizeof(Query_cache_block)))); |
973 | DBUG_VOID_RETURN; |
974 | } |
975 | |
976 | |
977 | void Query_cache_query::unlock_n_destroy() |
978 | { |
979 | DBUG_ENTER("Query_cache_query::unlock_n_destroy" ); |
980 | DBUG_PRINT("qcache" , ("destroyed & unlocked query for block %p" , |
981 | (uchar*) this - |
982 | ALIGN_SIZE(sizeof(Query_cache_block)))); |
983 | /* |
984 | The following call is not needed on system where one can destroy an |
985 | active semaphore |
986 | */ |
987 | this->unlock_writing(); |
988 | mysql_rwlock_destroy(&lock); |
989 | DBUG_VOID_RETURN; |
990 | } |
991 | |
992 | |
993 | extern "C" |
994 | { |
995 | uchar *query_cache_query_get_key(const uchar *record, size_t *length, |
996 | my_bool not_used) |
997 | { |
998 | Query_cache_block *query_block = (Query_cache_block*) record; |
999 | *length = (query_block->used - query_block->headers_len() - |
1000 | ALIGN_SIZE(sizeof(Query_cache_query))); |
1001 | return (((uchar *) query_block->data()) + |
1002 | ALIGN_SIZE(sizeof(Query_cache_query))); |
1003 | } |
1004 | } |
1005 | |
1006 | /***************************************************************************** |
1007 | Functions to store things into the query cache |
1008 | *****************************************************************************/ |
1009 | |
1010 | /* |
1011 | Note on double-check locking (DCL) usage. |
1012 | |
1013 | Below, in query_cache_insert(), query_cache_abort() and |
1014 | Query_cache::end_of_result() we use what is called double-check |
1015 | locking (DCL) for Query_cache_tls::first_query_block. |
1016 | I.e. we test it first without a lock, and, if positive, test again |
1017 | under the lock. |
1018 | |
1019 | This means that if we see 'first_query_block == 0' without a |
1020 | lock we will skip the operation. But this is safe here: when we |
1021 | started to cache a query, we called Query_cache::store_query(), and |
1022 | 'first_query_block' was set to non-zero in this thread (and the |
1023 | thread always sees results of its memory operations, mutex or not). |
1024 | If later we see 'first_query_block == 0' without locking a |
1025 | mutex, that may only mean that some other thread have reset it by |
1026 | invalidating the query. Skipping the operation in this case is the |
1027 | right thing to do, as first_query_block won't get non-zero for |
1028 | this query again. |
1029 | |
1030 | See also comments in Query_cache::store_query() and |
1031 | Query_cache::send_result_to_client(). |
1032 | |
1033 | NOTE, however, that double-check locking is not applicable in |
1034 | 'invalidate' functions, as we may erroneously skip invalidation, |
1035 | because the thread doing invalidation may never see non-zero |
1036 | 'first_query_block'. |
1037 | */ |
1038 | |
1039 | |
1040 | /** |
1041 | libmysql convenience wrapper to insert data into query cache. |
1042 | */ |
1043 | void query_cache_insert(void *thd_arg, const char *packet, size_t length, |
1044 | unsigned pkt_nr) |
1045 | { |
1046 | THD *thd= (THD*) thd_arg; |
1047 | |
1048 | /* |
1049 | Current_thd can be NULL when a new connection is immediately ended |
1050 | due to "Too many connections". thd->store_globals() has not been |
1051 | called at this time and hence set_current_thd(this) has not been |
1052 | called for this thread. |
1053 | */ |
1054 | |
1055 | if (unlikely(!thd)) |
1056 | return; |
1057 | |
1058 | query_cache.insert(thd, &thd->query_cache_tls, |
1059 | packet, (size_t)length, |
1060 | pkt_nr); |
1061 | } |
1062 | |
1063 | |
1064 | /** |
1065 | Insert the packet into the query cache. |
1066 | */ |
1067 | |
1068 | void |
1069 | Query_cache::insert(THD *thd, Query_cache_tls *query_cache_tls, |
1070 | const char *packet, size_t length, |
1071 | unsigned pkt_nr) |
1072 | { |
1073 | DBUG_ENTER("Query_cache::insert" ); |
1074 | |
1075 | /* First we check if query cache is disable without doing a mutex lock */ |
1076 | if (is_disabled() || query_cache_tls->first_query_block == NULL) |
1077 | DBUG_VOID_RETURN; |
1078 | |
1079 | QC_DEBUG_SYNC("wait_in_query_cache_insert" ); |
1080 | |
1081 | /* |
1082 | Lock the cache with try_lock(). try_lock() will fail if |
1083 | cache was disabled between the above test and lock. |
1084 | */ |
1085 | if (try_lock(thd, Query_cache::WAIT)) |
1086 | DBUG_VOID_RETURN; |
1087 | |
1088 | Query_cache_block *query_block = query_cache_tls->first_query_block; |
1089 | if (query_block == NULL) |
1090 | { |
1091 | /* |
1092 | We lost the writer and the currently processed query has been |
1093 | invalidated; there is nothing left to do. |
1094 | */ |
1095 | unlock(); |
1096 | DBUG_VOID_RETURN; |
1097 | } |
1098 | BLOCK_LOCK_WR(query_block); |
1099 | Query_cache_query *= query_block->query(); |
1100 | Query_cache_block *result= header->result(); |
1101 | |
1102 | DUMP(this); |
1103 | DBUG_PRINT("qcache" , ("insert packet %zu bytes long" ,length)); |
1104 | |
1105 | /* |
1106 | On success, STRUCT_UNLOCK is done by append_result_data. Otherwise, we |
1107 | still need structure_guard_mutex to free the query, and therefore unlock |
1108 | it later in this function. |
1109 | */ |
1110 | if (!append_result_data(&result, length, (uchar*) packet, |
1111 | query_block)) |
1112 | { |
1113 | DBUG_PRINT("warning" , ("Can't append data" )); |
1114 | header->result(result); |
1115 | DBUG_PRINT("qcache" , ("free query %p" , query_block)); |
1116 | // The following call will remove the lock on query_block |
1117 | query_cache.free_query(query_block); |
1118 | query_cache.refused++; |
1119 | // append_result_data no success => we need unlock |
1120 | unlock(); |
1121 | DBUG_VOID_RETURN; |
1122 | } |
1123 | |
1124 | header->result(result); |
1125 | header->last_pkt_nr= pkt_nr; |
1126 | BLOCK_UNLOCK_WR(query_block); |
1127 | DBUG_EXECUTE("check_querycache" ,check_integrity(0);); |
1128 | |
1129 | DBUG_VOID_RETURN; |
1130 | } |
1131 | |
1132 | |
1133 | void |
1134 | Query_cache::abort(THD *thd, Query_cache_tls *query_cache_tls) |
1135 | { |
1136 | DBUG_ENTER("query_cache_abort" ); |
1137 | |
1138 | /* See the comment on double-check locking usage above. */ |
1139 | if (is_disabled() || query_cache_tls->first_query_block == NULL) |
1140 | DBUG_VOID_RETURN; |
1141 | |
1142 | if (try_lock(thd, Query_cache::WAIT)) |
1143 | DBUG_VOID_RETURN; |
1144 | |
1145 | /* |
1146 | While we were waiting another thread might have changed the status |
1147 | of the writer. Make sure the writer still exists before continue. |
1148 | */ |
1149 | Query_cache_block *query_block= query_cache_tls->first_query_block; |
1150 | if (query_block) |
1151 | { |
1152 | THD_STAGE_INFO(thd, stage_storing_result_in_query_cache); |
1153 | DUMP(this); |
1154 | BLOCK_LOCK_WR(query_block); |
1155 | // The following call will remove the lock on query_block |
1156 | free_query(query_block); |
1157 | query_cache_tls->first_query_block= NULL; |
1158 | DBUG_EXECUTE("check_querycache" , check_integrity(1);); |
1159 | } |
1160 | |
1161 | unlock(); |
1162 | |
1163 | DBUG_VOID_RETURN; |
1164 | } |
1165 | |
1166 | |
1167 | void Query_cache::end_of_result(THD *thd) |
1168 | { |
1169 | Query_cache_block *query_block; |
1170 | Query_cache_tls *query_cache_tls= &thd->query_cache_tls; |
1171 | ulonglong limit_found_rows= thd->limit_found_rows; |
1172 | DBUG_ENTER("Query_cache::end_of_result" ); |
1173 | |
1174 | /* See the comment on double-check locking usage above. */ |
1175 | if (query_cache_tls->first_query_block == NULL) |
1176 | DBUG_VOID_RETURN; |
1177 | |
1178 | /* Ensure that only complete results are cached. */ |
1179 | DBUG_ASSERT(thd->get_stmt_da()->is_eof()); |
1180 | |
1181 | if (thd->killed) |
1182 | { |
1183 | query_cache_abort(thd, &thd->query_cache_tls); |
1184 | DBUG_VOID_RETURN; |
1185 | } |
1186 | |
1187 | #ifdef EMBEDDED_LIBRARY |
1188 | insert(thd, query_cache_tls, (char*)thd, |
1189 | emb_count_querycache_size(thd), 0); |
1190 | #endif |
1191 | |
1192 | if (try_lock(thd, Query_cache::WAIT)) |
1193 | { |
1194 | if (is_disabled()) |
1195 | query_cache_tls->first_query_block= NULL; // do not try again with QC |
1196 | DBUG_VOID_RETURN; |
1197 | } |
1198 | |
1199 | query_block= query_cache_tls->first_query_block; |
1200 | if (query_block) |
1201 | { |
1202 | /* |
1203 | The writer is still present; finish last result block by chopping it to |
1204 | suitable size if needed and setting block type. Since this is the last |
1205 | block, the writer should be dropped. |
1206 | */ |
1207 | THD_STAGE_INFO(thd, stage_storing_result_in_query_cache); |
1208 | DUMP(this); |
1209 | BLOCK_LOCK_WR(query_block); |
1210 | Query_cache_query *= query_block->query(); |
1211 | Query_cache_block *last_result_block; |
1212 | size_t allign_size; |
1213 | size_t len; |
1214 | |
1215 | if (header->result() == 0) |
1216 | { |
1217 | DBUG_PRINT("error" , ("End of data with no result blocks; " |
1218 | "Query '%s' removed from cache." , header->query())); |
1219 | /* |
1220 | Extra safety: empty result should not happen in the normal call |
1221 | to this function. In the release version that query should be ignored |
1222 | and removed from QC. |
1223 | */ |
1224 | DBUG_ASSERT(0); |
1225 | free_query(query_block); |
1226 | unlock(); |
1227 | DBUG_VOID_RETURN; |
1228 | } |
1229 | last_result_block= header->result()->prev; |
1230 | allign_size= ALIGN_SIZE(last_result_block->used); |
1231 | len= MY_MAX(query_cache.min_allocation_unit, allign_size); |
1232 | if (last_result_block->length >= query_cache.min_allocation_unit + len) |
1233 | query_cache.split_block(last_result_block,len); |
1234 | |
1235 | header->found_rows(limit_found_rows); |
1236 | header->set_results_ready(); // signal for plugin |
1237 | header->result()->type= Query_cache_block::RESULT; |
1238 | |
1239 | /* Drop the writer. */ |
1240 | header->writer(0); |
1241 | query_cache_tls->first_query_block= NULL; |
1242 | BLOCK_UNLOCK_WR(query_block); |
1243 | DBUG_EXECUTE("check_querycache" , check_integrity(1);); |
1244 | } |
1245 | |
1246 | unlock(); |
1247 | DBUG_VOID_RETURN; |
1248 | } |
1249 | |
1250 | void query_cache_invalidate_by_MyISAM_filename(const char *filename) |
1251 | { |
1252 | query_cache.invalidate_by_MyISAM_filename(filename); |
1253 | DBUG_EXECUTE("check_querycache" ,query_cache.check_integrity(0);); |
1254 | } |
1255 | |
1256 | |
1257 | /* |
1258 | The following function forms part of the C plugin API |
1259 | */ |
1260 | extern "C" |
1261 | void mysql_query_cache_invalidate4(THD *thd, |
1262 | const char *key, unsigned key_length, |
1263 | int using_trx) |
1264 | { |
1265 | query_cache.invalidate(thd, key, (uint32) key_length, (my_bool) using_trx); |
1266 | } |
1267 | |
1268 | |
1269 | /***************************************************************************** |
1270 | Query_cache methods |
1271 | *****************************************************************************/ |
1272 | |
1273 | Query_cache::Query_cache(size_t query_cache_limit_arg, |
1274 | size_t min_allocation_unit_arg, |
1275 | size_t min_result_data_size_arg, |
1276 | uint def_query_hash_size_arg, |
1277 | uint def_table_hash_size_arg) |
1278 | :query_cache_size(0), |
1279 | query_cache_limit(query_cache_limit_arg), |
1280 | queries_in_cache(0), hits(0), inserts(0), refused(0), |
1281 | total_blocks(0), lowmem_prunes(0), |
1282 | m_cache_status(OK), |
1283 | min_allocation_unit(ALIGN_SIZE(min_allocation_unit_arg)), |
1284 | min_result_data_size(ALIGN_SIZE(min_result_data_size_arg)), |
1285 | def_query_hash_size(ALIGN_SIZE(def_query_hash_size_arg)), |
1286 | def_table_hash_size(ALIGN_SIZE(def_table_hash_size_arg)), |
1287 | initialized(0) |
1288 | { |
1289 | size_t min_needed= (ALIGN_SIZE(sizeof(Query_cache_block)) + |
1290 | ALIGN_SIZE(sizeof(Query_cache_block_table)) + |
1291 | ALIGN_SIZE(sizeof(Query_cache_query)) + 3); |
1292 | set_if_bigger(min_allocation_unit,min_needed); |
1293 | this->min_allocation_unit= ALIGN_SIZE(min_allocation_unit); |
1294 | set_if_bigger(this->min_result_data_size,min_allocation_unit); |
1295 | } |
1296 | |
1297 | |
1298 | size_t Query_cache::resize(size_t query_cache_size_arg) |
1299 | { |
1300 | size_t new_query_cache_size; |
1301 | DBUG_ENTER("Query_cache::resize" ); |
1302 | DBUG_PRINT("qcache" , ("from %zu to %zu" ,query_cache_size, |
1303 | query_cache_size_arg)); |
1304 | DBUG_ASSERT(initialized); |
1305 | |
1306 | lock_and_suspend(); |
1307 | |
1308 | /* |
1309 | Wait for all readers and writers to exit. When the list of all queries |
1310 | is iterated over with a block level lock, we are done. |
1311 | */ |
1312 | Query_cache_block *block= queries_blocks; |
1313 | if (block) |
1314 | { |
1315 | do |
1316 | { |
1317 | BLOCK_LOCK_WR(block); |
1318 | Query_cache_query *query= block->query(); |
1319 | if (query->writer()) |
1320 | { |
1321 | /* |
1322 | Drop the writer; this will cancel any attempts to store |
1323 | the processed statement associated with this writer. |
1324 | */ |
1325 | query->writer()->first_query_block= NULL; |
1326 | query->writer(0); |
1327 | refused++; |
1328 | } |
1329 | query->unlock_n_destroy(); |
1330 | block= block->next; |
1331 | } while (block != queries_blocks); |
1332 | queries_blocks= NULL; // avoid second destroying by free_cache |
1333 | } |
1334 | free_cache(); |
1335 | |
1336 | query_cache_size= query_cache_size_arg; |
1337 | new_query_cache_size= init_cache(); |
1338 | |
1339 | /* |
1340 | m_cache_status is internal query cache switch so switching it on/off |
1341 | will not be reflected on global_system_variables.query_cache_type |
1342 | */ |
1343 | if (new_query_cache_size && global_system_variables.query_cache_type != 0) |
1344 | { |
1345 | DBUG_EXECUTE("check_querycache" ,check_integrity(1);); |
1346 | m_cache_status= OK; // size > 0 => enable cache |
1347 | } |
1348 | else |
1349 | m_cache_status= DISABLED; // size 0 means the cache disabled |
1350 | |
1351 | unlock(); |
1352 | DBUG_RETURN(new_query_cache_size); |
1353 | } |
1354 | |
1355 | |
1356 | size_t Query_cache::set_min_res_unit(size_t size) |
1357 | { |
1358 | DBUG_ASSERT(size % 8 == 0); |
1359 | if (size < min_allocation_unit) |
1360 | size= ALIGN_SIZE(min_allocation_unit); |
1361 | return (min_result_data_size= size); |
1362 | } |
1363 | |
1364 | |
1365 | void Query_cache::store_query(THD *thd, TABLE_LIST *tables_used) |
1366 | { |
1367 | TABLE_COUNTER_TYPE local_tables; |
1368 | size_t tot_length; |
1369 | const char *query; |
1370 | size_t query_length; |
1371 | uint8 tables_type; |
1372 | DBUG_ENTER("Query_cache::store_query" ); |
1373 | /* |
1374 | Testing 'query_cache_size' without a lock here is safe: the thing |
1375 | we may loose is that the query won't be cached, but we save on |
1376 | mutex locking in the case when query cache is disabled or the |
1377 | query is uncachable. |
1378 | |
1379 | See also a note on double-check locking usage above. |
1380 | */ |
1381 | if (!thd->query_cache_is_applicable || query_cache_size == 0) |
1382 | { |
1383 | DBUG_PRINT("qcache" , ("Query cache not ready" )); |
1384 | DBUG_VOID_RETURN; |
1385 | } |
1386 | if (thd->lex->sql_command != SQLCOM_SELECT) |
1387 | { |
1388 | DBUG_PRINT("qcache" , ("Ignoring not SELECT command" )); |
1389 | DBUG_VOID_RETURN; |
1390 | } |
1391 | |
1392 | /* |
1393 | Do not store queries while tracking transaction state. |
1394 | The tracker already flags queries that actually have |
1395 | transaction tracker items, but this will make behavior |
1396 | more straight forward. |
1397 | */ |
1398 | #ifndef EMBEDDED_LIBRARY |
1399 | if (thd->variables.session_track_transaction_info != TX_TRACK_NONE) |
1400 | { |
1401 | DBUG_PRINT("qcache" , ("Do not work with transaction tracking" )); |
1402 | DBUG_VOID_RETURN; |
1403 | } |
1404 | #endif //EMBEDDED_LIBRARY |
1405 | |
1406 | |
1407 | /* The following assert fails if we haven't called send_result_to_client */ |
1408 | DBUG_ASSERT(thd->base_query.is_alloced() || |
1409 | thd->base_query.ptr() == thd->query()); |
1410 | |
1411 | tables_type= 0; |
1412 | if ((local_tables= is_cacheable(thd, thd->lex, tables_used, |
1413 | &tables_type))) |
1414 | { |
1415 | NET *net= &thd->net; |
1416 | Query_cache_query_flags flags; |
1417 | // fill all gaps between fields with 0 to get repeatable key |
1418 | bzero(&flags, QUERY_CACHE_FLAGS_SIZE); |
1419 | flags.client_long_flag= MY_TEST(thd->client_capabilities & CLIENT_LONG_FLAG); |
1420 | flags.client_protocol_41= MY_TEST(thd->client_capabilities & |
1421 | CLIENT_PROTOCOL_41); |
1422 | flags.client_depr_eof= MY_TEST(thd->client_capabilities & |
1423 | CLIENT_DEPRECATE_EOF); |
1424 | /* |
1425 | Protocol influences result format, so statement results in the binary |
1426 | protocol (COM_EXECUTE) cannot be served to statements asking for results |
1427 | in the text protocol (COM_QUERY) and vice-versa. |
1428 | */ |
1429 | flags.protocol_type= (unsigned int) thd->protocol->type(); |
1430 | /* PROTOCOL_LOCAL results are not cached. */ |
1431 | DBUG_ASSERT(flags.protocol_type != (unsigned int) Protocol::PROTOCOL_LOCAL); |
1432 | flags.more_results_exists= MY_TEST(thd->server_status & |
1433 | SERVER_MORE_RESULTS_EXISTS); |
1434 | flags.in_trans= thd->in_active_multi_stmt_transaction(); |
1435 | flags.autocommit= MY_TEST(thd->server_status & SERVER_STATUS_AUTOCOMMIT); |
1436 | flags.pkt_nr= net->pkt_nr; |
1437 | flags.character_set_client_num= |
1438 | thd->variables.character_set_client->number; |
1439 | flags.character_set_results_num= |
1440 | (thd->variables.character_set_results ? |
1441 | thd->variables.character_set_results->number : |
1442 | UINT_MAX); |
1443 | flags.collation_connection_num= |
1444 | thd->variables.collation_connection->number; |
1445 | flags.limit= thd->variables.select_limit; |
1446 | flags.time_zone= thd->variables.time_zone; |
1447 | flags.sql_mode= thd->variables.sql_mode; |
1448 | flags.max_sort_length= thd->variables.max_sort_length; |
1449 | flags.lc_time_names= thd->variables.lc_time_names; |
1450 | flags.group_concat_max_len= thd->variables.group_concat_max_len; |
1451 | flags.div_precision_increment= thd->variables.div_precincrement; |
1452 | flags.default_week_format= thd->variables.default_week_format; |
1453 | DBUG_PRINT("qcache" , ("\ |
1454 | long %d, 4.1: %d, eof: %d, bin_proto: %d, more results %d, pkt_nr: %d, \ |
1455 | CS client: %u, CS result: %u, CS conn: %u, limit: %llu, TZ: %p, \ |
1456 | sql mode: 0x%llx, sort len: %llu, conncat len: %llu, div_precision: %zu, \ |
1457 | def_week_frmt: %zu, in_trans: %d, autocommit: %d" , |
1458 | (int)flags.client_long_flag, |
1459 | (int)flags.client_protocol_41, |
1460 | (int)flags.client_depr_eof, |
1461 | (int)flags.protocol_type, |
1462 | (int)flags.more_results_exists, |
1463 | flags.pkt_nr, |
1464 | flags.character_set_client_num, |
1465 | flags.character_set_results_num, |
1466 | flags.collation_connection_num, |
1467 | (ulonglong)flags.limit, |
1468 | flags.time_zone, |
1469 | flags.sql_mode, |
1470 | flags.max_sort_length, |
1471 | flags.group_concat_max_len, |
1472 | flags.div_precision_increment, |
1473 | flags.default_week_format, |
1474 | (int)flags.in_trans, |
1475 | (int)flags.autocommit)); |
1476 | |
1477 | /* |
1478 | A table- or a full flush operation can potentially take a long time to |
1479 | finish. We choose not to wait for them and skip caching statements |
1480 | instead. |
1481 | |
1482 | In case the wait time can't be determined there is an upper limit which |
1483 | causes try_lock() to abort with a time out. |
1484 | |
1485 | The 'TIMEOUT' parameter indicate that the lock is allowed to timeout |
1486 | |
1487 | */ |
1488 | if (try_lock(thd, Query_cache::TIMEOUT)) |
1489 | DBUG_VOID_RETURN; |
1490 | if (query_cache_size == 0) |
1491 | { |
1492 | unlock(); |
1493 | DBUG_VOID_RETURN; |
1494 | } |
1495 | DUMP(this); |
1496 | |
1497 | if (ask_handler_allowance(thd, tables_used)) |
1498 | { |
1499 | refused++; |
1500 | unlock(); |
1501 | DBUG_VOID_RETURN; |
1502 | } |
1503 | |
1504 | query= thd->base_query.ptr(); |
1505 | query_length= thd->base_query.length(); |
1506 | |
1507 | /* Key is query + database + flag */ |
1508 | if (thd->db.length) |
1509 | { |
1510 | memcpy((char*) (query + query_length + 1 + QUERY_CACHE_DB_LENGTH_SIZE), |
1511 | thd->db.str, thd->db.length); |
1512 | DBUG_PRINT("qcache" , ("database: %s length: %u" , |
1513 | thd->db.str, (unsigned) thd->db.length)); |
1514 | } |
1515 | else |
1516 | { |
1517 | DBUG_PRINT("qcache" , ("No active database" )); |
1518 | } |
1519 | tot_length= (query_length + thd->db.length + 1 + |
1520 | QUERY_CACHE_DB_LENGTH_SIZE + QUERY_CACHE_FLAGS_SIZE); |
1521 | /* |
1522 | We should only copy structure (don't use it location directly) |
1523 | because of alignment issue |
1524 | */ |
1525 | memcpy((void*) (query + (tot_length - QUERY_CACHE_FLAGS_SIZE)), |
1526 | &flags, QUERY_CACHE_FLAGS_SIZE); |
1527 | |
1528 | /* Check if another thread is processing the same query? */ |
1529 | Query_cache_block *competitor = (Query_cache_block *) |
1530 | my_hash_search(&queries, (uchar*) query, tot_length); |
1531 | DBUG_PRINT("qcache" , ("competitor %p" , competitor)); |
1532 | if (competitor == 0) |
1533 | { |
1534 | /* Query is not in cache and no one is working with it; Store it */ |
1535 | Query_cache_block *query_block; |
1536 | query_block= write_block_data(tot_length, (uchar*) query, |
1537 | ALIGN_SIZE(sizeof(Query_cache_query)), |
1538 | Query_cache_block::QUERY, local_tables); |
1539 | if (query_block != 0) |
1540 | { |
1541 | DBUG_PRINT("qcache" , ("query block %p allocated, %zu" , |
1542 | query_block, query_block->used)); |
1543 | |
1544 | Query_cache_query * = query_block->query(); |
1545 | header->init_n_lock(); |
1546 | if (my_hash_insert(&queries, (uchar*) query_block)) |
1547 | { |
1548 | refused++; |
1549 | DBUG_PRINT("qcache" , ("insertion in query hash" )); |
1550 | header->unlock_n_destroy(); |
1551 | free_memory_block(query_block); |
1552 | unlock(); |
1553 | goto end; |
1554 | } |
1555 | if (!register_all_tables(thd, query_block, tables_used, local_tables)) |
1556 | { |
1557 | refused++; |
1558 | DBUG_PRINT("warning" , ("tables list including failed" )); |
1559 | my_hash_delete(&queries, (uchar *) query_block); |
1560 | header->unlock_n_destroy(); |
1561 | free_memory_block(query_block); |
1562 | unlock(); |
1563 | goto end; |
1564 | } |
1565 | double_linked_list_simple_include(query_block, &queries_blocks); |
1566 | inserts++; |
1567 | queries_in_cache++; |
1568 | thd->query_cache_tls.first_query_block= query_block; |
1569 | header->writer(&thd->query_cache_tls); |
1570 | header->tables_type(tables_type); |
1571 | |
1572 | unlock(); |
1573 | |
1574 | DEBUG_SYNC(thd, "wait_in_query_cache_store_query" ); |
1575 | |
1576 | // init_n_lock make query block locked |
1577 | BLOCK_UNLOCK_WR(query_block); |
1578 | } |
1579 | else |
1580 | { |
1581 | // We have not enough memory to store query => do nothing |
1582 | refused++; |
1583 | unlock(); |
1584 | DBUG_PRINT("warning" , ("Can't allocate query" )); |
1585 | } |
1586 | } |
1587 | else |
1588 | { |
1589 | // Another thread is processing the same query => do nothing |
1590 | refused++; |
1591 | unlock(); |
1592 | DBUG_PRINT("qcache" , ("Another thread process same query" )); |
1593 | } |
1594 | } |
1595 | else |
1596 | statistic_increment(refused, &structure_guard_mutex); |
1597 | |
1598 | end: |
1599 | DBUG_VOID_RETURN; |
1600 | } |
1601 | |
1602 | |
1603 | #ifndef EMBEDDED_LIBRARY |
1604 | /** |
1605 | Send a single memory block from the query cache. |
1606 | |
1607 | Respects the client/server protocol limits for the |
1608 | size of the network packet, and splits a large block |
1609 | in pieces to ensure that individual piece doesn't exceed |
1610 | the maximal allowed size of the network packet (16M). |
1611 | |
1612 | @param[in] net NET handler |
1613 | @param[in] packet packet to send |
1614 | @param[in] len packet length |
1615 | |
1616 | @return Operation status |
1617 | @retval FALSE On success |
1618 | @retval TRUE On error |
1619 | */ |
1620 | static bool |
1621 | send_data_in_chunks(NET *net, const uchar *packet, size_t len) |
1622 | { |
1623 | /* |
1624 | On the client we may require more memory than max_allowed_packet |
1625 | to keep, both, the truncated last logical packet, and the |
1626 | compressed next packet. This never (or in practice never) |
1627 | happens without compression, since without compression it's very |
1628 | unlikely that a) a truncated logical packet would remain on the |
1629 | client when it's time to read the next packet b) a subsequent |
1630 | logical packet that is being read would be so large that |
1631 | size-of-new-packet + size-of-old-packet-tail > |
1632 | max_allowed_packet. To remedy this issue, we send data in 1MB |
1633 | sized packets, that's below the current client default of 16MB |
1634 | for max_allowed_packet, but large enough to ensure there is no |
1635 | unnecessary overhead from too many syscalls per result set. |
1636 | */ |
1637 | static const size_t MAX_CHUNK_LENGTH= 1024*1024; |
1638 | |
1639 | while (len > MAX_CHUNK_LENGTH) |
1640 | { |
1641 | if (net_real_write(net, packet, MAX_CHUNK_LENGTH)) |
1642 | return TRUE; |
1643 | packet+= MAX_CHUNK_LENGTH; |
1644 | len-= MAX_CHUNK_LENGTH; |
1645 | } |
1646 | if (len && net_real_write(net, packet, len)) |
1647 | return TRUE; |
1648 | |
1649 | return FALSE; |
1650 | } |
1651 | #endif |
1652 | |
1653 | |
1654 | /** |
1655 | Build a normalized table name suitable for query cache engine callback |
1656 | |
1657 | This consist of normalized directory '/' normalized_file_name |
1658 | followed by suffix. |
1659 | Suffix is needed for partitioned tables. |
1660 | */ |
1661 | |
1662 | size_t build_normalized_name(char *buff, size_t bufflen, |
1663 | const char *db, size_t db_len, |
1664 | const char *table_name, size_t table_len, |
1665 | size_t suffix_len) |
1666 | { |
1667 | uint errors; |
1668 | size_t length; |
1669 | char *pos= buff, *end= buff+bufflen; |
1670 | DBUG_ENTER("build_normalized_name" ); |
1671 | |
1672 | (*pos++)= FN_LIBCHAR; |
1673 | length= strconvert(system_charset_info, db, db_len, |
1674 | &my_charset_filename, pos, bufflen - 3, |
1675 | &errors); |
1676 | pos+= length; |
1677 | (*pos++)= FN_LIBCHAR; |
1678 | length= strconvert(system_charset_info, table_name, table_len, |
1679 | &my_charset_filename, pos, (uint) (end - pos), |
1680 | &errors); |
1681 | pos+= length; |
1682 | if (pos + suffix_len < end) |
1683 | pos= strmake(pos, table_name + table_len, suffix_len); |
1684 | |
1685 | DBUG_RETURN((size_t) (pos - buff)); |
1686 | } |
1687 | |
1688 | |
1689 | /* |
1690 | Check if the query is in the cache. If it was cached, send it |
1691 | to the user. |
1692 | |
1693 | @param thd Pointer to the thread handler |
1694 | @param org_sql A pointer to the sql statement * |
1695 | @param query_length Length of the statement in characters |
1696 | |
1697 | @return status code |
1698 | @retval 0 Query was not cached. |
1699 | @retval 1 The query was cached and user was sent the result. |
1700 | @retval -1 The query was cached but we didn't have rights to use it. |
1701 | |
1702 | In case of -1, no error is sent to the client. |
1703 | |
1704 | *) The buffer must be allocated memory of size: |
1705 | tot_length= query_length + thd->db.length + 1 + QUERY_CACHE_FLAGS_SIZE; |
1706 | */ |
1707 | |
1708 | int |
1709 | Query_cache::send_result_to_client(THD *thd, char *org_sql, uint query_length) |
1710 | { |
1711 | ulonglong engine_data; |
1712 | Query_cache_query *query; |
1713 | #ifndef EMBEDDED_LIBRARY |
1714 | Query_cache_block *first_result_block; |
1715 | #endif |
1716 | Query_cache_block *result_block; |
1717 | Query_cache_block_table *block_table, *block_table_end; |
1718 | size_t tot_length; |
1719 | Query_cache_query_flags flags; |
1720 | const char *sql, *sql_end, *found_brace= 0; |
1721 | DBUG_ENTER("Query_cache::send_result_to_client" ); |
1722 | |
1723 | /* |
1724 | Testing without a lock here is safe: the thing |
1725 | we may loose is that the query won't be served from cache, but we |
1726 | save on mutex locking in the case when query cache is disabled. |
1727 | |
1728 | See also a note on double-check locking usage above. |
1729 | */ |
1730 | if (is_disabled() || thd->locked_tables_mode || |
1731 | thd->variables.query_cache_type == 0) |
1732 | goto err; |
1733 | |
1734 | /* |
1735 | The following can only happen for prepared statements that was found |
1736 | during parsing or later that the query was not cacheable. |
1737 | */ |
1738 | if (!thd->lex->safe_to_cache_query) |
1739 | { |
1740 | DBUG_PRINT("qcache" , ("SELECT is non-cacheable" )); |
1741 | goto err; |
1742 | } |
1743 | |
1744 | /* |
1745 | Don't allow serving from Query_cache while tracking transaction |
1746 | state. This is a safeguard in case an otherwise matching query |
1747 | was added to the cache before tracking was turned on. |
1748 | */ |
1749 | #ifndef EMBEDDED_LIBRARY |
1750 | if (thd->variables.session_track_transaction_info != TX_TRACK_NONE) |
1751 | { |
1752 | DBUG_PRINT("qcache" , ("Do not work with transaction tracking" )); |
1753 | goto err; |
1754 | } |
1755 | #endif //EMBEDDED_LIBRARY |
1756 | |
1757 | |
1758 | thd->query_cache_is_applicable= 1; |
1759 | sql= org_sql; sql_end= sql + query_length; |
1760 | |
1761 | /* |
1762 | Skip all comments at start of query. The following tests is false for |
1763 | all normal queries. |
1764 | */ |
1765 | if (!my_isalpha(system_charset_info, *sql)) |
1766 | { |
1767 | while (sql < sql_end) |
1768 | { |
1769 | char current= *sql; |
1770 | switch (current) { |
1771 | case '/': |
1772 | if (sql[1] != '*') |
1773 | break; |
1774 | sql+= 2; // Skip '/*' |
1775 | if (*sql == '!') |
1776 | { |
1777 | /* |
1778 | Found / *!number comment; Skip number to see if sql |
1779 | starts with 'select' |
1780 | */ |
1781 | sql++; |
1782 | while (my_isdigit(system_charset_info, *sql)) |
1783 | sql++; |
1784 | } |
1785 | else |
1786 | { |
1787 | while (sql++ < sql_end) |
1788 | { |
1789 | if (sql[-1] == '*' && *sql == '/') |
1790 | { |
1791 | sql++; |
1792 | break; |
1793 | } |
1794 | } |
1795 | } |
1796 | continue; |
1797 | case '-': |
1798 | if (sql[1] != '-' || !is_white_space(sql[2])) // Not a comment |
1799 | break; |
1800 | sql++; // Skip first '-' |
1801 | /* Fall through */ |
1802 | case '#': |
1803 | while (++sql < sql_end) |
1804 | { |
1805 | if (*sql == '\n') |
1806 | { |
1807 | sql++; // Skip '\n' |
1808 | break; |
1809 | } |
1810 | } |
1811 | /* Continue with analyzing current symbol */ |
1812 | continue; |
1813 | case '\r': |
1814 | case '\n': |
1815 | case '\t': |
1816 | case ' ': |
1817 | sql++; |
1818 | continue; |
1819 | case '(': // To handle (select a from t1) union (select a from t1); |
1820 | if (!found_brace) |
1821 | { |
1822 | found_brace= sql; |
1823 | sql++; |
1824 | continue; |
1825 | } |
1826 | /* fall through */ |
1827 | default: |
1828 | break; |
1829 | } |
1830 | /* We only come here when we found the first word of the sql */ |
1831 | break; |
1832 | } |
1833 | } |
1834 | if ((my_toupper(system_charset_info, sql[0]) != 'S' || |
1835 | my_toupper(system_charset_info, sql[1]) != 'E' || |
1836 | my_toupper(system_charset_info, sql[2]) != 'L') && |
1837 | (my_toupper(system_charset_info, sql[0]) != 'W' || |
1838 | my_toupper(system_charset_info, sql[1]) != 'I' || |
1839 | my_toupper(system_charset_info, sql[2]) != 'T')) |
1840 | { |
1841 | DBUG_PRINT("qcache" , ("The statement is not a SELECT; Not cached" )); |
1842 | goto err; |
1843 | } |
1844 | |
1845 | if ((sql_end - sql) > 20 && has_no_cache_directive(sql+6)) |
1846 | { |
1847 | /* |
1848 | We do not increase 'refused' statistics here since it will be done |
1849 | later when the query is parsed. |
1850 | */ |
1851 | DBUG_PRINT("qcache" , ("The statement has a SQL_NO_CACHE directive" )); |
1852 | goto err; |
1853 | } |
1854 | { |
1855 | /* |
1856 | We have allocated buffer space (in alloc_query) to hold the |
1857 | SQL statement(s) + the current database name + a flags struct. |
1858 | If the database name has changed during execution, which might |
1859 | happen if there are multiple statements, we need to make |
1860 | sure the new current database has a name with the same length |
1861 | as the previous one. |
1862 | */ |
1863 | size_t db_len= uint2korr(sql_end+1); |
1864 | if (thd->db.length != db_len) |
1865 | { |
1866 | /* |
1867 | We should probably reallocate the buffer in this case, |
1868 | but for now we just leave it uncached |
1869 | */ |
1870 | |
1871 | DBUG_PRINT("qcache" , |
1872 | ("Current database has changed since start of query" )); |
1873 | goto err; |
1874 | } |
1875 | } |
1876 | /* |
1877 | Try to obtain an exclusive lock on the query cache. If the cache is |
1878 | disabled or if a full cache flush is in progress, the attempt to |
1879 | get the lock is aborted. |
1880 | |
1881 | The TIMEOUT parameter indicate that the lock is allowed to timeout. |
1882 | */ |
1883 | if (try_lock(thd, Query_cache::TIMEOUT)) |
1884 | goto err; |
1885 | |
1886 | if (query_cache_size == 0) |
1887 | { |
1888 | thd->query_cache_is_applicable= 0; // Query can't be cached |
1889 | goto err_unlock; |
1890 | } |
1891 | |
1892 | Query_cache_block *query_block; |
1893 | if (thd->variables.query_cache_strip_comments) |
1894 | { |
1895 | if (found_brace) |
1896 | sql= found_brace; |
1897 | make_base_query(&thd->base_query, sql, (size_t) (sql_end - sql), |
1898 | thd->db.length + 1 + QUERY_CACHE_DB_LENGTH_SIZE + |
1899 | QUERY_CACHE_FLAGS_SIZE); |
1900 | sql= thd->base_query.ptr(); |
1901 | query_length= thd->base_query.length(); |
1902 | } |
1903 | else |
1904 | { |
1905 | sql= org_sql; |
1906 | thd->base_query.set(sql, query_length, system_charset_info); |
1907 | } |
1908 | |
1909 | tot_length= (query_length + 1 + QUERY_CACHE_DB_LENGTH_SIZE + |
1910 | thd->db.length + QUERY_CACHE_FLAGS_SIZE); |
1911 | |
1912 | if (thd->db.length) |
1913 | { |
1914 | memcpy((uchar*) sql + query_length + 1 + QUERY_CACHE_DB_LENGTH_SIZE, |
1915 | thd->db.str, thd->db.length); |
1916 | DBUG_PRINT("qcache" , ("database: '%s' length: %u" , |
1917 | thd->db.str, (uint) thd->db.length)); |
1918 | } |
1919 | else |
1920 | { |
1921 | DBUG_PRINT("qcache" , ("No active database" )); |
1922 | } |
1923 | |
1924 | THD_STAGE_INFO(thd, stage_checking_query_cache_for_query); |
1925 | |
1926 | // fill all gaps between fields with 0 to get repeatable key |
1927 | bzero(&flags, QUERY_CACHE_FLAGS_SIZE); |
1928 | flags.client_long_flag= MY_TEST(thd->client_capabilities & CLIENT_LONG_FLAG); |
1929 | flags.client_protocol_41= MY_TEST(thd->client_capabilities & |
1930 | CLIENT_PROTOCOL_41); |
1931 | flags.client_depr_eof= MY_TEST(thd->client_capabilities & |
1932 | CLIENT_DEPRECATE_EOF); |
1933 | flags.protocol_type= (unsigned int) thd->protocol->type(); |
1934 | flags.more_results_exists= MY_TEST(thd->server_status & |
1935 | SERVER_MORE_RESULTS_EXISTS); |
1936 | flags.in_trans= thd->in_active_multi_stmt_transaction(); |
1937 | flags.autocommit= MY_TEST(thd->server_status & SERVER_STATUS_AUTOCOMMIT); |
1938 | flags.pkt_nr= thd->net.pkt_nr; |
1939 | flags.character_set_client_num= thd->variables.character_set_client->number; |
1940 | flags.character_set_results_num= |
1941 | (thd->variables.character_set_results ? |
1942 | thd->variables.character_set_results->number : |
1943 | UINT_MAX); |
1944 | flags.collation_connection_num= thd->variables.collation_connection->number; |
1945 | flags.limit= thd->variables.select_limit; |
1946 | flags.time_zone= thd->variables.time_zone; |
1947 | flags.sql_mode= thd->variables.sql_mode; |
1948 | flags.max_sort_length= thd->variables.max_sort_length; |
1949 | flags.group_concat_max_len= thd->variables.group_concat_max_len; |
1950 | flags.div_precision_increment= thd->variables.div_precincrement; |
1951 | flags.default_week_format= thd->variables.default_week_format; |
1952 | flags.lc_time_names= thd->variables.lc_time_names; |
1953 | DBUG_PRINT("qcache" , ("\ |
1954 | long %d, 4.1: %d, eof: %d, bin_proto: %d, more results %d, pkt_nr: %d, \ |
1955 | CS client: %u, CS result: %u, CS conn: %u, limit: %llu, TZ: %p, \ |
1956 | sql mode: 0x%llx, sort len: %llu, conncat len: %llu, div_precision: %zu, \ |
1957 | def_week_frmt: %zu, in_trans: %d, autocommit: %d" , |
1958 | (int)flags.client_long_flag, |
1959 | (int)flags.client_protocol_41, |
1960 | (int)flags.client_depr_eof, |
1961 | (int)flags.protocol_type, |
1962 | (int)flags.more_results_exists, |
1963 | flags.pkt_nr, |
1964 | flags.character_set_client_num, |
1965 | flags.character_set_results_num, |
1966 | flags.collation_connection_num, |
1967 | (ulonglong) flags.limit, |
1968 | flags.time_zone, |
1969 | flags.sql_mode, |
1970 | flags.max_sort_length, |
1971 | flags.group_concat_max_len, |
1972 | flags.div_precision_increment, |
1973 | flags.default_week_format, |
1974 | (int)flags.in_trans, |
1975 | (int)flags.autocommit)); |
1976 | memcpy((uchar *)(sql + (tot_length - QUERY_CACHE_FLAGS_SIZE)), |
1977 | (uchar*) &flags, QUERY_CACHE_FLAGS_SIZE); |
1978 | |
1979 | #ifdef WITH_WSREP |
1980 | bool once_more; |
1981 | once_more= true; |
1982 | lookup: |
1983 | #endif /* WITH_WSREP */ |
1984 | |
1985 | query_block = (Query_cache_block *) my_hash_search(&queries, (uchar*) sql, |
1986 | tot_length); |
1987 | /* Quick abort on unlocked data */ |
1988 | if (query_block == 0 || |
1989 | query_block->query()->result() == 0 || |
1990 | query_block->query()->result()->type != Query_cache_block::RESULT) |
1991 | { |
1992 | DBUG_PRINT("qcache" , ("No query in query hash or no results" )); |
1993 | goto err_unlock; |
1994 | } |
1995 | DBUG_PRINT("qcache" , ("Query in query hash %p" ,query_block)); |
1996 | |
1997 | #ifdef WITH_WSREP |
1998 | if (once_more && WSREP_CLIENT(thd) && wsrep_must_sync_wait(thd)) |
1999 | { |
2000 | unlock(); |
2001 | if (wsrep_sync_wait(thd)) |
2002 | goto err; |
2003 | if (try_lock(thd, Query_cache::TIMEOUT)) |
2004 | goto err; |
2005 | once_more= false; |
2006 | goto lookup; |
2007 | } |
2008 | #endif /* WITH_WSREP */ |
2009 | |
2010 | /* Now lock and test that nothing changed while blocks was unlocked */ |
2011 | BLOCK_LOCK_RD(query_block); |
2012 | |
2013 | query = query_block->query(); |
2014 | result_block= query->result(); |
2015 | #ifndef EMBEDDED_LIBRARY |
2016 | first_result_block= result_block; |
2017 | #endif |
2018 | |
2019 | if (result_block == 0 || result_block->type != Query_cache_block::RESULT) |
2020 | { |
2021 | /* The query is probably yet processed */ |
2022 | DBUG_PRINT("qcache" , ("query found, but no data or data incomplete" )); |
2023 | BLOCK_UNLOCK_RD(query_block); |
2024 | goto err_unlock; |
2025 | } |
2026 | DBUG_PRINT("qcache" , ("Query have result %p" , query)); |
2027 | |
2028 | if (thd->in_multi_stmt_transaction_mode() && |
2029 | (query->tables_type() & HA_CACHE_TBL_TRANSACT)) |
2030 | { |
2031 | DBUG_PRINT("qcache" , |
2032 | ("we are in transaction and have transaction tables in query" )); |
2033 | BLOCK_UNLOCK_RD(query_block); |
2034 | goto err_unlock; |
2035 | } |
2036 | |
2037 | // Check access; |
2038 | THD_STAGE_INFO(thd, stage_checking_privileges_on_cached_query); |
2039 | block_table= query_block->table(0); |
2040 | block_table_end= block_table+query_block->n_tables; |
2041 | for (; block_table != block_table_end; block_table++) |
2042 | { |
2043 | TABLE_LIST table_list; |
2044 | TMP_TABLE_SHARE *tmptable; |
2045 | Query_cache_table *table = block_table->parent; |
2046 | |
2047 | /* |
2048 | Check that we do not have temporary tables with same names as that of |
2049 | base tables from this query. If we have such tables, we will not send |
2050 | data from query cache, because temporary tables hide real tables by which |
2051 | query in query cache was made. |
2052 | */ |
2053 | if ((tmptable= |
2054 | thd->find_tmp_table_share_w_base_key((char *) table->data(), |
2055 | table->key_length()))) |
2056 | { |
2057 | DBUG_PRINT("qcache" , |
2058 | ("Temporary table detected: '%s.%s'" , |
2059 | tmptable->db.str, tmptable->table_name.str)); |
2060 | unlock(); |
2061 | /* |
2062 | We should not store result of this query because it contain |
2063 | temporary tables => assign following variable to make check |
2064 | faster. |
2065 | */ |
2066 | thd->query_cache_is_applicable= 0; // Query can't be cached |
2067 | thd->lex->safe_to_cache_query= 0; // For prepared statements |
2068 | BLOCK_UNLOCK_RD(query_block); |
2069 | DBUG_RETURN(-1); |
2070 | } |
2071 | |
2072 | bzero((char*) &table_list,sizeof(table_list)); |
2073 | table_list.db.str= table->db(); |
2074 | table_list.db.length= strlen(table_list.db.str); |
2075 | table_list.alias.str= table_list.table_name.str= table->table(); |
2076 | table_list.alias.length= table_list.table_name.length= strlen(table->table()); |
2077 | |
2078 | #ifndef NO_EMBEDDED_ACCESS_CHECKS |
2079 | if (check_table_access(thd,SELECT_ACL,&table_list, FALSE, 1,TRUE)) |
2080 | { |
2081 | DBUG_PRINT("qcache" , |
2082 | ("probably no SELECT access to %s.%s => return to normal processing" , |
2083 | table_list.db.str, table_list.alias.str)); |
2084 | unlock(); |
2085 | thd->query_cache_is_applicable= 0; // Query can't be cached |
2086 | thd->lex->safe_to_cache_query= 0; // For prepared statements |
2087 | BLOCK_UNLOCK_RD(query_block); |
2088 | DBUG_RETURN(-1); // Privilege error |
2089 | } |
2090 | if (table_list.grant.want_privilege) |
2091 | { |
2092 | DBUG_PRINT("qcache" , ("Need to check column privileges for %s.%s" , |
2093 | table_list.db.str, table_list.alias.str)); |
2094 | BLOCK_UNLOCK_RD(query_block); |
2095 | thd->query_cache_is_applicable= 0; // Query can't be cached |
2096 | thd->lex->safe_to_cache_query= 0; // For prepared statements |
2097 | goto err_unlock; // Parse query |
2098 | } |
2099 | #endif /*!NO_EMBEDDED_ACCESS_CHECKS*/ |
2100 | engine_data= table->engine_data(); |
2101 | if (table->callback()) |
2102 | { |
2103 | char qcache_se_key_name[FN_REFLEN + 10]; |
2104 | size_t qcache_se_key_len, db_length= strlen(table->db()); |
2105 | engine_data= table->engine_data(); |
2106 | |
2107 | qcache_se_key_len= build_normalized_name(qcache_se_key_name, |
2108 | sizeof(qcache_se_key_name), |
2109 | table->db(), |
2110 | db_length, |
2111 | table->table(), |
2112 | table->key_length() - |
2113 | db_length - 2 - |
2114 | table->suffix_length(), |
2115 | table->suffix_length()); |
2116 | |
2117 | if (!(*table->callback())(thd, qcache_se_key_name, |
2118 | (uint)qcache_se_key_len, &engine_data)) |
2119 | { |
2120 | DBUG_PRINT("qcache" , ("Handler does not allow caching for %.*s" , |
2121 | (int)qcache_se_key_len, qcache_se_key_name)); |
2122 | BLOCK_UNLOCK_RD(query_block); |
2123 | if (engine_data != table->engine_data()) |
2124 | { |
2125 | DBUG_PRINT("qcache" , |
2126 | ("Handler require invalidation queries of %.*s %llu-%llu" , |
2127 | (int)qcache_se_key_len, qcache_se_key_name, |
2128 | engine_data, table->engine_data())); |
2129 | invalidate_table_internal(thd, |
2130 | (uchar *) table->db(), |
2131 | table->key_length()); |
2132 | } |
2133 | else |
2134 | { |
2135 | /* |
2136 | As this can change from call to call, don't reset set |
2137 | thd->lex->safe_to_cache_query |
2138 | */ |
2139 | thd->query_cache_is_applicable= 0; // Query can't be cached |
2140 | } |
2141 | /* |
2142 | End the statement transaction potentially started by engine. |
2143 | Currently our engines do not request rollback from callbacks. |
2144 | If this is going to change code needs to be reworked. |
2145 | */ |
2146 | DBUG_ASSERT(! thd->transaction_rollback_request); |
2147 | trans_rollback_stmt(thd); |
2148 | goto err_unlock; // Parse query |
2149 | } |
2150 | } |
2151 | else |
2152 | DBUG_PRINT("qcache" , ("handler allow caching %s,%s" , |
2153 | table_list.db.str, table_list.alias.str)); |
2154 | } |
2155 | move_to_query_list_end(query_block); |
2156 | hits++; |
2157 | query->increment_hits(); |
2158 | unlock(); |
2159 | |
2160 | /* |
2161 | Send cached result to client |
2162 | */ |
2163 | #ifndef EMBEDDED_LIBRARY |
2164 | THD_STAGE_INFO(thd, stage_sending_cached_result_to_client); |
2165 | do |
2166 | { |
2167 | DBUG_PRINT("qcache" , ("Results (len: %zu used: %zu headers: %u)" , |
2168 | result_block->length, result_block->used, |
2169 | (uint) (result_block->headers_len()+ |
2170 | ALIGN_SIZE(sizeof(Query_cache_result))))); |
2171 | |
2172 | Query_cache_result *result = result_block->result(); |
2173 | if (send_data_in_chunks(&thd->net, result->data(), |
2174 | result_block->used - |
2175 | result_block->headers_len() - |
2176 | ALIGN_SIZE(sizeof(Query_cache_result)))) |
2177 | break; // Client aborted |
2178 | result_block = result_block->next; |
2179 | thd->net.pkt_nr= query->last_pkt_nr; // Keep packet number updated |
2180 | } while (result_block != first_result_block); |
2181 | #else |
2182 | { |
2183 | Querycache_stream qs(result_block, result_block->headers_len() + |
2184 | ALIGN_SIZE(sizeof(Query_cache_result))); |
2185 | emb_load_querycache_result(thd, &qs); |
2186 | } |
2187 | #endif /*!EMBEDDED_LIBRARY*/ |
2188 | |
2189 | thd->set_sent_row_count(thd->limit_found_rows = query->found_rows()); |
2190 | thd->status_var.last_query_cost= 0.0; |
2191 | thd->query_plan_flags= (thd->query_plan_flags & ~QPLAN_QC_NO) | QPLAN_QC; |
2192 | if (!thd->get_sent_row_count()) |
2193 | status_var_increment(thd->status_var.empty_queries); |
2194 | else |
2195 | status_var_add(thd->status_var.rows_sent, thd->get_sent_row_count()); |
2196 | |
2197 | /* |
2198 | End the statement transaction potentially started by an |
2199 | engine callback. We ignore the return value for now, |
2200 | since as long as EOF packet is part of the query cache |
2201 | response, we can't handle it anyway. |
2202 | */ |
2203 | (void) trans_commit_stmt(thd); |
2204 | thd->get_stmt_da()->disable_status(); |
2205 | |
2206 | BLOCK_UNLOCK_RD(query_block); |
2207 | MYSQL_QUERY_CACHE_HIT(thd->query(), thd->limit_found_rows); |
2208 | DBUG_RETURN(1); // Result sent to client |
2209 | |
2210 | err_unlock: |
2211 | unlock(); |
2212 | MYSQL_QUERY_CACHE_MISS(thd->query()); |
2213 | /* |
2214 | query_plan_flags doesn't have to be changed here as it contains |
2215 | QPLAN_QC_NO by default |
2216 | */ |
2217 | DBUG_RETURN(0); // Query was not cached |
2218 | |
2219 | err: |
2220 | thd->query_cache_is_applicable= 0; // Query can't be cached |
2221 | DBUG_RETURN(0); // Query was not cached |
2222 | } |
2223 | |
2224 | |
2225 | /* |
2226 | Remove all cached queries that uses any of the tables in the list |
2227 | */ |
2228 | |
2229 | void Query_cache::invalidate(THD *thd, TABLE_LIST *tables_used, |
2230 | my_bool using_transactions) |
2231 | { |
2232 | DBUG_ENTER("Query_cache::invalidate (table list)" ); |
2233 | if (is_disabled()) |
2234 | DBUG_VOID_RETURN; |
2235 | |
2236 | using_transactions= using_transactions && thd->in_multi_stmt_transaction_mode(); |
2237 | for (; tables_used; tables_used= tables_used->next_local) |
2238 | { |
2239 | DBUG_ASSERT(!using_transactions || tables_used->table!=0); |
2240 | if (tables_used->derived) |
2241 | continue; |
2242 | if (using_transactions && |
2243 | (tables_used->table->file->table_cache_type() == |
2244 | HA_CACHE_TBL_TRANSACT)) |
2245 | /* |
2246 | tables_used->table can't be 0 in transaction. |
2247 | Only 'drop' invalidate not opened table, but 'drop' |
2248 | force transaction finish. |
2249 | */ |
2250 | thd->add_changed_table(tables_used->table); |
2251 | else |
2252 | invalidate_table(thd, tables_used); |
2253 | } |
2254 | |
2255 | DEBUG_SYNC(thd, "wait_after_query_cache_invalidate" ); |
2256 | |
2257 | DBUG_VOID_RETURN; |
2258 | } |
2259 | |
2260 | void Query_cache::invalidate(THD *thd, CHANGED_TABLE_LIST *tables_used) |
2261 | { |
2262 | DBUG_ENTER("Query_cache::invalidate (changed table list)" ); |
2263 | if (is_disabled()) |
2264 | DBUG_VOID_RETURN; |
2265 | |
2266 | for (; tables_used; tables_used= tables_used->next) |
2267 | { |
2268 | THD_STAGE_INFO(thd, stage_invalidating_query_cache_entries_table_list); |
2269 | invalidate_table(thd, (uchar*) tables_used->key, tables_used->key_length); |
2270 | DBUG_PRINT("qcache" , ("db: %s table: %s" , tables_used->key, |
2271 | tables_used->key+ |
2272 | strlen(tables_used->key)+1)); |
2273 | } |
2274 | DBUG_VOID_RETURN; |
2275 | } |
2276 | |
2277 | |
2278 | /* |
2279 | Invalidate locked for write |
2280 | |
2281 | SYNOPSIS |
2282 | Query_cache::invalidate_locked_for_write() |
2283 | tables_used - table list |
2284 | |
2285 | NOTE |
2286 | can be used only for opened tables |
2287 | */ |
2288 | void Query_cache::invalidate_locked_for_write(THD *thd, |
2289 | TABLE_LIST *tables_used) |
2290 | { |
2291 | DBUG_ENTER("Query_cache::invalidate_locked_for_write" ); |
2292 | if (is_disabled()) |
2293 | DBUG_VOID_RETURN; |
2294 | |
2295 | for (; tables_used; tables_used= tables_used->next_local) |
2296 | { |
2297 | THD_STAGE_INFO(thd, stage_invalidating_query_cache_entries_table); |
2298 | if (tables_used->lock_type >= TL_WRITE_ALLOW_WRITE && |
2299 | tables_used->table) |
2300 | { |
2301 | invalidate_table(thd, tables_used->table); |
2302 | } |
2303 | } |
2304 | DBUG_VOID_RETURN; |
2305 | } |
2306 | |
2307 | /* |
2308 | Remove all cached queries that uses the given table |
2309 | */ |
2310 | |
2311 | void Query_cache::invalidate(THD *thd, TABLE *table, |
2312 | my_bool using_transactions) |
2313 | { |
2314 | DBUG_ENTER("Query_cache::invalidate (table)" ); |
2315 | if (is_disabled()) |
2316 | DBUG_VOID_RETURN; |
2317 | |
2318 | using_transactions= using_transactions && thd->in_multi_stmt_transaction_mode(); |
2319 | if (using_transactions && |
2320 | (table->file->table_cache_type() == HA_CACHE_TBL_TRANSACT)) |
2321 | thd->add_changed_table(table); |
2322 | else |
2323 | invalidate_table(thd, table); |
2324 | |
2325 | |
2326 | DBUG_VOID_RETURN; |
2327 | } |
2328 | |
2329 | void Query_cache::invalidate(THD *thd, const char *key, size_t key_length, |
2330 | my_bool using_transactions) |
2331 | { |
2332 | DBUG_ENTER("Query_cache::invalidate (key)" ); |
2333 | if (is_disabled()) |
2334 | DBUG_VOID_RETURN; |
2335 | |
2336 | using_transactions= using_transactions && thd->in_multi_stmt_transaction_mode(); |
2337 | if (using_transactions) // used for innodb => has_transactions() is TRUE |
2338 | thd->add_changed_table(key, key_length); |
2339 | else |
2340 | invalidate_table(thd, (uchar*)key, key_length); |
2341 | |
2342 | DBUG_VOID_RETURN; |
2343 | } |
2344 | |
2345 | |
2346 | /** |
2347 | Remove all cached queries that uses the given database. |
2348 | */ |
2349 | |
2350 | void Query_cache::invalidate(THD *thd, const char *db) |
2351 | { |
2352 | DBUG_ENTER("Query_cache::invalidate (db)" ); |
2353 | if (is_disabled()) |
2354 | DBUG_VOID_RETURN; |
2355 | |
2356 | DBUG_SLOW_ASSERT(ok_for_lower_case_names(db)); |
2357 | |
2358 | bool restart= FALSE; |
2359 | /* |
2360 | Lock the query cache and queue all invalidation attempts to avoid |
2361 | the risk of a race between invalidation, cache inserts and flushes. |
2362 | */ |
2363 | lock(thd); |
2364 | |
2365 | if (query_cache_size > 0) |
2366 | { |
2367 | if (tables_blocks) |
2368 | { |
2369 | Query_cache_block *table_block = tables_blocks; |
2370 | do { |
2371 | restart= FALSE; |
2372 | do |
2373 | { |
2374 | Query_cache_block *next= table_block->next; |
2375 | Query_cache_table *table = table_block->table(); |
2376 | if (strcmp(table->db(),db) == 0) |
2377 | { |
2378 | Query_cache_block_table *list_root= table_block->table(0); |
2379 | invalidate_query_block_list(thd,list_root); |
2380 | } |
2381 | |
2382 | table_block= next; |
2383 | |
2384 | /* |
2385 | If our root node to used tables became null then the last element |
2386 | in the table list was removed when a query was invalidated; |
2387 | Terminate the search. |
2388 | */ |
2389 | if (tables_blocks == 0) |
2390 | { |
2391 | table_block= tables_blocks; |
2392 | } |
2393 | /* |
2394 | If the iterated list has changed underlying structure; |
2395 | we need to restart the search. |
2396 | */ |
2397 | else if (table_block->type == Query_cache_block::FREE) |
2398 | { |
2399 | restart= TRUE; |
2400 | table_block= tables_blocks; |
2401 | } |
2402 | /* |
2403 | The used tables are linked in a circular list; |
2404 | loop until we return to the beginning. |
2405 | */ |
2406 | } while (table_block != tables_blocks); |
2407 | /* |
2408 | Invalidating a table will also mean that all cached queries using |
2409 | this table also will be invalidated. This will in turn change the |
2410 | list of tables associated with these queries and the linked list of |
2411 | used table will be changed. Because of this we might need to restart |
2412 | the search when a table has been invalidated. |
2413 | */ |
2414 | } while (restart); |
2415 | } // end if( tables_blocks ) |
2416 | } |
2417 | unlock(); |
2418 | |
2419 | DBUG_VOID_RETURN; |
2420 | } |
2421 | |
2422 | |
2423 | void Query_cache::invalidate_by_MyISAM_filename(const char *filename) |
2424 | { |
2425 | DBUG_ENTER("Query_cache::invalidate_by_MyISAM_filename" ); |
2426 | |
2427 | if (is_disabled()) |
2428 | DBUG_VOID_RETURN; |
2429 | |
2430 | /* Calculate the key outside the lock to make the lock shorter */ |
2431 | char key[MAX_DBKEY_LENGTH]; |
2432 | uint32 db_length; |
2433 | uint key_length= filename_2_table_key(key, filename, &db_length); |
2434 | THD *thd= current_thd; |
2435 | invalidate_table(thd,(uchar *)key, key_length); |
2436 | DBUG_VOID_RETURN; |
2437 | } |
2438 | |
2439 | /* Remove all queries from cache */ |
2440 | |
2441 | void Query_cache::flush() |
2442 | { |
2443 | DBUG_ENTER("Query_cache::flush" ); |
2444 | if (is_disabled()) |
2445 | DBUG_VOID_RETURN; |
2446 | |
2447 | QC_DEBUG_SYNC("wait_in_query_cache_flush1" ); |
2448 | |
2449 | lock_and_suspend(); |
2450 | if (query_cache_size > 0) |
2451 | { |
2452 | DUMP(this); |
2453 | flush_cache(); |
2454 | DUMP(this); |
2455 | } |
2456 | |
2457 | DBUG_EXECUTE("check_querycache" ,query_cache.check_integrity(1);); |
2458 | unlock(); |
2459 | DBUG_VOID_RETURN; |
2460 | } |
2461 | |
2462 | |
2463 | /** |
2464 | Rearrange the memory blocks and join result in cache in 1 block (if |
2465 | result length > join_limit) |
2466 | |
2467 | @param[in] join_limit If the minimum length of a result block to be joined. |
2468 | @param[in] iteration_limit The maximum number of packing and joining |
2469 | sequences. |
2470 | |
2471 | */ |
2472 | |
2473 | void Query_cache::pack(THD *thd, size_t join_limit, uint iteration_limit) |
2474 | { |
2475 | DBUG_ENTER("Query_cache::pack" ); |
2476 | |
2477 | if (is_disabled()) |
2478 | DBUG_VOID_RETURN; |
2479 | |
2480 | /* |
2481 | If the entire qc is being invalidated we can bail out early |
2482 | instead of waiting for the lock. |
2483 | */ |
2484 | if (try_lock(thd, Query_cache::WAIT)) |
2485 | DBUG_VOID_RETURN; |
2486 | |
2487 | if (query_cache_size == 0) |
2488 | { |
2489 | unlock(); |
2490 | DBUG_VOID_RETURN; |
2491 | } |
2492 | |
2493 | uint i = 0; |
2494 | do |
2495 | { |
2496 | pack_cache(); |
2497 | } while ((++i < iteration_limit) && join_results(join_limit)); |
2498 | |
2499 | unlock(); |
2500 | DBUG_VOID_RETURN; |
2501 | } |
2502 | |
2503 | |
2504 | void Query_cache::destroy() |
2505 | { |
2506 | DBUG_ENTER("Query_cache::destroy" ); |
2507 | if (!initialized) |
2508 | { |
2509 | DBUG_PRINT("qcache" , ("Query Cache not initialized" )); |
2510 | } |
2511 | else |
2512 | { |
2513 | /* Underlying code expects the lock. */ |
2514 | lock_and_suspend(); |
2515 | free_cache(); |
2516 | unlock(); |
2517 | |
2518 | mysql_cond_destroy(&COND_cache_status_changed); |
2519 | mysql_mutex_destroy(&structure_guard_mutex); |
2520 | initialized = 0; |
2521 | DBUG_ASSERT(m_requests_in_progress == 0); |
2522 | } |
2523 | DBUG_VOID_RETURN; |
2524 | } |
2525 | |
2526 | |
2527 | void Query_cache::disable_query_cache(THD *thd) |
2528 | { |
2529 | m_cache_status= DISABLE_REQUEST; |
2530 | /* |
2531 | If there is no requests in progress try to free buffer. |
2532 | try_lock(TRY) will exit immediately if there is lock. |
2533 | unlock() should free block. |
2534 | */ |
2535 | if (m_requests_in_progress == 0 && !try_lock(thd, TRY)) |
2536 | unlock(); |
2537 | } |
2538 | |
2539 | |
2540 | /***************************************************************************** |
2541 | init/destroy |
2542 | *****************************************************************************/ |
2543 | |
2544 | void Query_cache::init() |
2545 | { |
2546 | DBUG_ENTER("Query_cache::init" ); |
2547 | mysql_mutex_init(key_structure_guard_mutex, |
2548 | &structure_guard_mutex, MY_MUTEX_INIT_FAST); |
2549 | mysql_cond_init(key_COND_cache_status_changed, |
2550 | &COND_cache_status_changed, NULL); |
2551 | m_cache_lock_status= Query_cache::UNLOCKED; |
2552 | m_cache_status= Query_cache::OK; |
2553 | m_requests_in_progress= 0; |
2554 | initialized = 1; |
2555 | /* |
2556 | Using state_map from latin1 should be fine in all cases: |
2557 | 1. We do not support UCS2, UTF16, UTF32 as a client character set. |
2558 | 2. The other character sets are compatible on the lower ASCII-range |
2559 | 0x00-0x20, and have the following characters marked as spaces: |
2560 | |
2561 | 0x09 TAB |
2562 | 0x0A LINE FEED |
2563 | 0x0B VERTICAL TAB |
2564 | 0x0C FORM FEED |
2565 | 0x0D CARRIAGE RETUR |
2566 | 0x20 SPACE |
2567 | |
2568 | Additionally, only some of the ASCII-compatible character sets |
2569 | (including latin1) can have 0xA0 mapped to "NON-BREAK SPACE" |
2570 | and thus marked as space. |
2571 | That should not be a problem for those charsets that map 0xA0 |
2572 | to something else: the parser will just return syntax error |
2573 | if this character appears straight in the query |
2574 | (i.e. not inside a string literal or comment). |
2575 | */ |
2576 | query_state_map= my_charset_latin1.state_map; |
2577 | /* |
2578 | If we explicitly turn off query cache from the command line query |
2579 | cache will be disabled for the reminder of the server life |
2580 | time. This is because we want to avoid locking the QC specific |
2581 | mutex if query cache isn't going to be used. |
2582 | */ |
2583 | if (global_system_variables.query_cache_type == 0) |
2584 | { |
2585 | m_cache_status= DISABLE_REQUEST; |
2586 | free_cache(); |
2587 | m_cache_status= DISABLED; |
2588 | } |
2589 | DBUG_VOID_RETURN; |
2590 | } |
2591 | |
2592 | |
2593 | size_t Query_cache::init_cache() |
2594 | { |
2595 | size_t mem_bin_count, num, step; |
2596 | size_t mem_bin_size, prev_size, inc; |
2597 | size_t max_mem_bin_size, approx_additional_data_size; |
2598 | int align; |
2599 | |
2600 | DBUG_ENTER("Query_cache::init_cache" ); |
2601 | |
2602 | approx_additional_data_size = (sizeof(Query_cache) + |
2603 | sizeof(uchar*)*(def_query_hash_size+ |
2604 | def_table_hash_size)); |
2605 | if (query_cache_size < approx_additional_data_size) |
2606 | goto err; |
2607 | |
2608 | query_cache_size-= approx_additional_data_size; |
2609 | align= query_cache_size % ALIGN_SIZE(1); |
2610 | if (align) |
2611 | { |
2612 | query_cache_size-= align; |
2613 | approx_additional_data_size+= align; |
2614 | } |
2615 | |
2616 | /* |
2617 | Count memory bins number. |
2618 | Check section 6. in start comment for the used algorithm. |
2619 | */ |
2620 | |
2621 | max_mem_bin_size = query_cache_size >> QUERY_CACHE_MEM_BIN_FIRST_STEP_PWR2; |
2622 | mem_bin_count = (uint) ((1 + QUERY_CACHE_MEM_BIN_PARTS_INC) * |
2623 | QUERY_CACHE_MEM_BIN_PARTS_MUL); |
2624 | mem_bin_num = 1; |
2625 | mem_bin_steps = 1; |
2626 | mem_bin_size = max_mem_bin_size >> QUERY_CACHE_MEM_BIN_STEP_PWR2; |
2627 | prev_size = 0; |
2628 | if (mem_bin_size <= min_allocation_unit) |
2629 | { |
2630 | DBUG_PRINT("qcache" , ("too small query cache => query cache disabled" )); |
2631 | // TODO here (and above) should be warning in 4.1 |
2632 | goto err; |
2633 | } |
2634 | while (mem_bin_size > min_allocation_unit) |
2635 | { |
2636 | mem_bin_num += mem_bin_count; |
2637 | prev_size = mem_bin_size; |
2638 | mem_bin_size >>= QUERY_CACHE_MEM_BIN_STEP_PWR2; |
2639 | mem_bin_steps++; |
2640 | mem_bin_count += QUERY_CACHE_MEM_BIN_PARTS_INC; |
2641 | mem_bin_count = (uint) (mem_bin_count * QUERY_CACHE_MEM_BIN_PARTS_MUL); |
2642 | |
2643 | // Prevent too small bins spacing |
2644 | if (mem_bin_count > (mem_bin_size >> QUERY_CACHE_MEM_BIN_SPC_LIM_PWR2)) |
2645 | mem_bin_count= (mem_bin_size >> QUERY_CACHE_MEM_BIN_SPC_LIM_PWR2); |
2646 | } |
2647 | inc = (prev_size - mem_bin_size) / mem_bin_count; |
2648 | mem_bin_num += (mem_bin_count - (min_allocation_unit - mem_bin_size)/inc); |
2649 | mem_bin_steps++; |
2650 | additional_data_size = ((mem_bin_num+1) * |
2651 | ALIGN_SIZE(sizeof(Query_cache_memory_bin))+ |
2652 | (mem_bin_steps * |
2653 | ALIGN_SIZE(sizeof(Query_cache_memory_bin_step)))); |
2654 | |
2655 | if (query_cache_size < additional_data_size) |
2656 | goto err; |
2657 | query_cache_size -= additional_data_size; |
2658 | |
2659 | if (!(cache= (uchar *) |
2660 | my_malloc_lock(query_cache_size+additional_data_size, MYF(0)))) |
2661 | goto err; |
2662 | #if defined(DBUG_OFF) && defined(HAVE_MADVISE) && defined(MADV_DONTDUMP) |
2663 | if (madvise(cache, query_cache_size+additional_data_size, MADV_DONTDUMP)) |
2664 | { |
2665 | DBUG_PRINT("warning" , ("coudn't mark query cache memory as MADV_DONTDUMP: %s" , |
2666 | strerror(errno))); |
2667 | } |
2668 | #endif |
2669 | |
2670 | DBUG_PRINT("qcache" , ("cache length %zu, min unit %zu, %zu bins" , |
2671 | query_cache_size, min_allocation_unit, mem_bin_num)); |
2672 | |
2673 | steps = (Query_cache_memory_bin_step *) cache; |
2674 | bins = ((Query_cache_memory_bin *) |
2675 | (cache + mem_bin_steps * |
2676 | ALIGN_SIZE(sizeof(Query_cache_memory_bin_step)))); |
2677 | |
2678 | first_block = (Query_cache_block *) (cache + additional_data_size); |
2679 | first_block->init(query_cache_size); |
2680 | total_blocks++; |
2681 | first_block->pnext=first_block->pprev=first_block; |
2682 | first_block->next=first_block->prev=first_block; |
2683 | |
2684 | /* Prepare bins */ |
2685 | |
2686 | bins[0].init(max_mem_bin_size); |
2687 | steps[0].init(max_mem_bin_size,0,0); |
2688 | mem_bin_count = (uint) ((1 + QUERY_CACHE_MEM_BIN_PARTS_INC) * |
2689 | QUERY_CACHE_MEM_BIN_PARTS_MUL); |
2690 | num= step= 1; |
2691 | mem_bin_size = max_mem_bin_size >> QUERY_CACHE_MEM_BIN_STEP_PWR2; |
2692 | while (mem_bin_size > min_allocation_unit) |
2693 | { |
2694 | size_t incr = (steps[step-1].size - mem_bin_size) / mem_bin_count; |
2695 | size_t size = mem_bin_size; |
2696 | for (size_t i= mem_bin_count; i > 0; i--) |
2697 | { |
2698 | bins[num+i-1].init(size); |
2699 | size += incr; |
2700 | } |
2701 | num += mem_bin_count; |
2702 | steps[step].init(mem_bin_size, num-1, incr); |
2703 | mem_bin_size >>= QUERY_CACHE_MEM_BIN_STEP_PWR2; |
2704 | step++; |
2705 | mem_bin_count += QUERY_CACHE_MEM_BIN_PARTS_INC; |
2706 | mem_bin_count = (uint) (mem_bin_count * QUERY_CACHE_MEM_BIN_PARTS_MUL); |
2707 | if (mem_bin_count > (mem_bin_size >> QUERY_CACHE_MEM_BIN_SPC_LIM_PWR2)) |
2708 | mem_bin_count=(mem_bin_size >> QUERY_CACHE_MEM_BIN_SPC_LIM_PWR2); |
2709 | } |
2710 | inc = (steps[step-1].size - mem_bin_size) / mem_bin_count; |
2711 | |
2712 | /* |
2713 | num + mem_bin_count > mem_bin_num, but index never be > mem_bin_num |
2714 | because block with size < min_allocated_unit never will be requested |
2715 | */ |
2716 | |
2717 | steps[step].init(mem_bin_size, num + mem_bin_count - 1, inc); |
2718 | { |
2719 | size_t skiped = (min_allocation_unit - mem_bin_size)/inc; |
2720 | size_t size = mem_bin_size + inc*skiped; |
2721 | size_t i = mem_bin_count - skiped; |
2722 | while (i-- > 0) |
2723 | { |
2724 | bins[num+i].init(size); |
2725 | size += inc; |
2726 | } |
2727 | } |
2728 | bins[mem_bin_num].number = 1; // For easy end test in get_free_block |
2729 | free_memory = free_memory_blocks = 0; |
2730 | insert_into_free_memory_list(first_block); |
2731 | |
2732 | DUMP(this); |
2733 | |
2734 | (void) my_hash_init(&queries, &my_charset_bin, def_query_hash_size, 0, 0, |
2735 | query_cache_query_get_key, 0, 0); |
2736 | #ifndef FN_NO_CASE_SENSE |
2737 | /* |
2738 | If lower_case_table_names!=0 then db and table names are already |
2739 | converted to lower case and we can use binary collation for their |
2740 | comparison (no matter if file system case sensitive or not). |
2741 | If we have case-sensitive file system (like on most Unixes) and |
2742 | lower_case_table_names == 0 then we should distinguish my_table |
2743 | and MY_TABLE cases and so again can use binary collation. |
2744 | */ |
2745 | (void) my_hash_init(&tables, &my_charset_bin, def_table_hash_size, 0, 0, |
2746 | query_cache_table_get_key, 0, 0); |
2747 | #else |
2748 | /* |
2749 | On windows, OS/2, MacOS X with HFS+ or any other case insensitive |
2750 | file system if lower_case_table_names!=0 we have same situation as |
2751 | in previous case, but if lower_case_table_names==0 then we should |
2752 | not distinguish cases (to be compatible in behavior with underlying |
2753 | file system) and so should use case insensitive collation for |
2754 | comparison. |
2755 | */ |
2756 | (void) my_hash_init(&tables, |
2757 | lower_case_table_names ? &my_charset_bin : |
2758 | files_charset_info, |
2759 | def_table_hash_size, 0, 0,query_cache_table_get_key, |
2760 | 0, 0); |
2761 | #endif |
2762 | |
2763 | queries_in_cache = 0; |
2764 | queries_blocks = 0; |
2765 | DBUG_RETURN(query_cache_size + |
2766 | additional_data_size + approx_additional_data_size); |
2767 | |
2768 | err: |
2769 | make_disabled(); |
2770 | DBUG_RETURN(0); |
2771 | } |
2772 | |
2773 | |
2774 | /* Disable the use of the query cache */ |
2775 | |
2776 | void Query_cache::make_disabled() |
2777 | { |
2778 | DBUG_ENTER("Query_cache::make_disabled" ); |
2779 | query_cache_size= 0; |
2780 | queries_blocks= 0; |
2781 | free_memory= 0; |
2782 | free_memory_blocks= 0; |
2783 | bins= 0; |
2784 | steps= 0; |
2785 | cache= 0; |
2786 | mem_bin_num= mem_bin_steps= 0; |
2787 | queries_in_cache= 0; |
2788 | first_block= 0; |
2789 | total_blocks= 0; |
2790 | tables_blocks= 0; |
2791 | DBUG_VOID_RETURN; |
2792 | } |
2793 | |
2794 | |
2795 | /** |
2796 | @class Query_cache |
2797 | Free all resources allocated by the cache. |
2798 | |
2799 | This function frees all resources allocated by the cache. You |
2800 | have to call init_cache() before using the cache again. This function |
2801 | requires the cache to be locked (LOCKED_NO_WAIT, lock_and_suspend) or |
2802 | disabling. |
2803 | */ |
2804 | |
2805 | void Query_cache::free_cache() |
2806 | { |
2807 | DBUG_ENTER("Query_cache::free_cache" ); |
2808 | |
2809 | DBUG_ASSERT(m_cache_lock_status == LOCKED_NO_WAIT || |
2810 | m_cache_status == DISABLE_REQUEST); |
2811 | |
2812 | /* Destroy locks */ |
2813 | Query_cache_block *block= queries_blocks; |
2814 | if (block) |
2815 | { |
2816 | do |
2817 | { |
2818 | Query_cache_query *query= block->query(); |
2819 | /* |
2820 | There will not be new requests but some maybe not finished yet, |
2821 | so wait for them by trying lock/unlock |
2822 | */ |
2823 | BLOCK_LOCK_WR(block); |
2824 | BLOCK_UNLOCK_WR(block); |
2825 | |
2826 | mysql_rwlock_destroy(&query->lock); |
2827 | block= block->next; |
2828 | } while (block != queries_blocks); |
2829 | } |
2830 | |
2831 | #if defined(DBUG_OFF) && defined(HAVE_MADVISE) && defined(MADV_DODUMP) |
2832 | if (madvise(cache, query_cache_size+additional_data_size, MADV_DODUMP)) |
2833 | { |
2834 | DBUG_PRINT("warning" , ("coudn't mark query cache memory as MADV_DODUMP: %s" , |
2835 | strerror(errno))); |
2836 | } |
2837 | #endif |
2838 | my_free(cache); |
2839 | make_disabled(); |
2840 | my_hash_free(&queries); |
2841 | my_hash_free(&tables); |
2842 | DBUG_VOID_RETURN; |
2843 | } |
2844 | |
2845 | /***************************************************************************** |
2846 | Free block data |
2847 | *****************************************************************************/ |
2848 | |
2849 | |
2850 | /** |
2851 | Flush the cache. |
2852 | |
2853 | This function will flush cache contents. It assumes we have |
2854 | 'structure_guard_mutex' locked. The function sets the m_cache_status flag and |
2855 | releases the lock, so other threads may proceed skipping the cache as if it |
2856 | is disabled. Concurrent flushes are performed in turn. |
2857 | After flush_cache() call, the cache is flushed, all the freed memory is |
2858 | accumulated in bin[0], and the 'structure_guard_mutex' is locked. However, |
2859 | since we could release the mutex during execution, the rest of the cache |
2860 | state could have been changed, and should not be relied on. |
2861 | */ |
2862 | |
2863 | void Query_cache::flush_cache() |
2864 | { |
2865 | QC_DEBUG_SYNC("wait_in_query_cache_flush2" ); |
2866 | |
2867 | my_hash_reset(&queries); |
2868 | while (queries_blocks != 0) |
2869 | { |
2870 | BLOCK_LOCK_WR(queries_blocks); |
2871 | free_query_internal(queries_blocks); |
2872 | } |
2873 | } |
2874 | |
2875 | /* |
2876 | Free oldest query that is not in use by another thread. |
2877 | Returns 1 if we couldn't remove anything |
2878 | */ |
2879 | |
2880 | my_bool Query_cache::free_old_query() |
2881 | { |
2882 | DBUG_ENTER("Query_cache::free_old_query" ); |
2883 | if (queries_blocks) |
2884 | { |
2885 | /* |
2886 | try_lock_writing used to prevent client because here lock |
2887 | sequence is breached. |
2888 | Also we don't need remove locked queries at this point. |
2889 | */ |
2890 | Query_cache_block *query_block= 0; |
2891 | if (queries_blocks != 0) |
2892 | { |
2893 | Query_cache_block *block = queries_blocks; |
2894 | /* Search until we find first query that we can remove */ |
2895 | do |
2896 | { |
2897 | Query_cache_query * = block->query(); |
2898 | if (header->result() != 0 && |
2899 | header->result()->type == Query_cache_block::RESULT && |
2900 | block->query()->try_lock_writing()) |
2901 | { |
2902 | query_block = block; |
2903 | break; |
2904 | } |
2905 | } while ((block=block->next) != queries_blocks ); |
2906 | } |
2907 | |
2908 | if (query_block != 0) |
2909 | { |
2910 | free_query(query_block); |
2911 | lowmem_prunes++; |
2912 | DBUG_RETURN(0); |
2913 | } |
2914 | } |
2915 | DBUG_RETURN(1); // Nothing to remove |
2916 | } |
2917 | |
2918 | |
2919 | /* |
2920 | free_query_internal() - free query from query cache. |
2921 | |
2922 | SYNOPSIS |
2923 | free_query_internal() |
2924 | query_block Query_cache_block representing the query |
2925 | |
2926 | DESCRIPTION |
2927 | This function will remove the query from a cache, and place its |
2928 | memory blocks to the list of free blocks. 'query_block' must be |
2929 | locked for writing, this function will release (and destroy) this |
2930 | lock. |
2931 | |
2932 | NOTE |
2933 | 'query_block' should be removed from 'queries' hash _before_ |
2934 | calling this method, as the lock will be destroyed here. |
2935 | */ |
2936 | |
2937 | void Query_cache::free_query_internal(Query_cache_block *query_block) |
2938 | { |
2939 | DBUG_ENTER("Query_cache::free_query_internal" ); |
2940 | DBUG_PRINT("qcache" , ("free query %p %zu bytes result" , |
2941 | query_block, |
2942 | query_block->query()->length() )); |
2943 | |
2944 | queries_in_cache--; |
2945 | |
2946 | Query_cache_query *query= query_block->query(); |
2947 | |
2948 | if (query->writer() != 0) |
2949 | { |
2950 | /* Tell MySQL that this query should not be cached anymore */ |
2951 | query->writer()->first_query_block= NULL; |
2952 | query->writer(0); |
2953 | } |
2954 | double_linked_list_exclude(query_block, &queries_blocks); |
2955 | Query_cache_block_table *table= query_block->table(0); |
2956 | |
2957 | for (TABLE_COUNTER_TYPE i= 0; i < query_block->n_tables; i++) |
2958 | unlink_table(table++); |
2959 | Query_cache_block *result_block= query->result(); |
2960 | |
2961 | /* |
2962 | The following is true when query destruction was called and no results |
2963 | in query . (query just registered and then abort/pack/flush called) |
2964 | */ |
2965 | if (result_block != 0) |
2966 | { |
2967 | if (result_block->type != Query_cache_block::RESULT) |
2968 | { |
2969 | // removing unfinished query |
2970 | refused++; |
2971 | inserts--; |
2972 | } |
2973 | Query_cache_block *block= result_block; |
2974 | do |
2975 | { |
2976 | Query_cache_block *current= block; |
2977 | block= block->next; |
2978 | free_memory_block(current); |
2979 | } while (block != result_block); |
2980 | } |
2981 | else |
2982 | { |
2983 | // removing unfinished query |
2984 | refused++; |
2985 | inserts--; |
2986 | } |
2987 | |
2988 | query->unlock_n_destroy(); |
2989 | free_memory_block(query_block); |
2990 | |
2991 | DBUG_VOID_RETURN; |
2992 | } |
2993 | |
2994 | |
2995 | /* |
2996 | free_query() - free query from query cache. |
2997 | |
2998 | SYNOPSIS |
2999 | free_query() |
3000 | query_block Query_cache_block representing the query |
3001 | |
3002 | DESCRIPTION |
3003 | This function will remove 'query_block' from 'queries' hash, and |
3004 | then call free_query_internal(), which see. |
3005 | */ |
3006 | |
3007 | void Query_cache::free_query(Query_cache_block *query_block) |
3008 | { |
3009 | DBUG_ENTER("Query_cache::free_query" ); |
3010 | DBUG_PRINT("qcache" , ("free query %p %zu bytes result" , |
3011 | query_block, |
3012 | query_block->query()->length() )); |
3013 | |
3014 | my_hash_delete(&queries,(uchar *) query_block); |
3015 | free_query_internal(query_block); |
3016 | |
3017 | DBUG_VOID_RETURN; |
3018 | } |
3019 | |
3020 | /***************************************************************************** |
3021 | Query data creation |
3022 | *****************************************************************************/ |
3023 | |
3024 | Query_cache_block * |
3025 | Query_cache::write_block_data(size_t data_len, uchar* data, |
3026 | size_t , |
3027 | Query_cache_block::block_type type, |
3028 | TABLE_COUNTER_TYPE ntab) |
3029 | { |
3030 | size_t = (ALIGN_SIZE(sizeof(Query_cache_block)) + |
3031 | ALIGN_SIZE(ntab*sizeof(Query_cache_block_table)) + |
3032 | header_len); |
3033 | size_t len = data_len + all_headers_len; |
3034 | size_t align_len= ALIGN_SIZE(len); |
3035 | DBUG_ENTER("Query_cache::write_block_data" ); |
3036 | DBUG_PRINT("qcache" , ("data: %zd, header: %zd, all header: %zd" , |
3037 | data_len, header_len, all_headers_len)); |
3038 | Query_cache_block *block= allocate_block(MY_MAX(align_len, |
3039 | min_allocation_unit),1, 0); |
3040 | if (block != 0) |
3041 | { |
3042 | block->type = type; |
3043 | block->n_tables = ntab; |
3044 | block->used = len; |
3045 | |
3046 | memcpy((uchar *) block+ all_headers_len, data, data_len); |
3047 | } |
3048 | DBUG_RETURN(block); |
3049 | } |
3050 | |
3051 | |
3052 | my_bool |
3053 | Query_cache::append_result_data(Query_cache_block **current_block, |
3054 | size_t data_len, uchar* data, |
3055 | Query_cache_block *query_block) |
3056 | { |
3057 | DBUG_ENTER("Query_cache::append_result_data" ); |
3058 | DBUG_PRINT("qcache" , ("append %zu bytes to %p query" , |
3059 | data_len, query_block)); |
3060 | |
3061 | if (query_block->query()->add(data_len) > query_cache_limit) |
3062 | { |
3063 | DBUG_PRINT("qcache" , ("size limit reached %zu > %zu" , |
3064 | query_block->query()->length(), |
3065 | query_cache_limit)); |
3066 | DBUG_RETURN(0); |
3067 | } |
3068 | if (*current_block == 0) |
3069 | { |
3070 | DBUG_PRINT("qcache" , ("allocated first result data block %zu" , data_len)); |
3071 | DBUG_RETURN(write_result_data(current_block, data_len, data, query_block, |
3072 | Query_cache_block::RES_BEG)); |
3073 | } |
3074 | Query_cache_block *last_block = (*current_block)->prev; |
3075 | |
3076 | DBUG_PRINT("qcache" , ("lastblock %p len %zu used %zu" , |
3077 | last_block, last_block->length, |
3078 | last_block->used)); |
3079 | my_bool success = 1; |
3080 | size_t last_block_free_space= last_block->length - last_block->used; |
3081 | |
3082 | /* |
3083 | We will first allocate and write the 'tail' of data, that doesn't fit |
3084 | in the 'last_block'. Only if this succeeds, we will fill the last_block. |
3085 | This saves us a memcpy if the query doesn't fit in the query cache. |
3086 | */ |
3087 | |
3088 | // Try join blocks if physically next block is free... |
3089 | size_t tail = data_len - last_block_free_space; |
3090 | size_t append_min = get_min_append_result_data_size(); |
3091 | if (last_block_free_space < data_len && |
3092 | append_next_free_block(last_block, |
3093 | MY_MAX(tail, append_min))) |
3094 | last_block_free_space = last_block->length - last_block->used; |
3095 | // If no space in last block (even after join) allocate new block |
3096 | if (last_block_free_space < data_len) |
3097 | { |
3098 | DBUG_PRINT("qcache" , ("allocate new block for %zu bytes" , |
3099 | data_len-last_block_free_space)); |
3100 | Query_cache_block *new_block = 0; |
3101 | success = write_result_data(&new_block, data_len-last_block_free_space, |
3102 | (uchar*)(((uchar*)data)+last_block_free_space), |
3103 | query_block, |
3104 | Query_cache_block::RES_CONT); |
3105 | /* |
3106 | new_block may be != 0 even !success (if write_result_data |
3107 | allocate a small block but failed to allocate continue) |
3108 | */ |
3109 | if (new_block != 0) |
3110 | double_linked_list_join(last_block, new_block); |
3111 | } |
3112 | else |
3113 | { |
3114 | // It is success (nobody can prevent us write data) |
3115 | unlock(); |
3116 | } |
3117 | |
3118 | // Now finally write data to the last block |
3119 | if (success && last_block_free_space > 0) |
3120 | { |
3121 | size_t to_copy = MY_MIN(data_len,last_block_free_space); |
3122 | DBUG_PRINT("qcache" , ("use free space %zub at block %p to copy %zub" , |
3123 | last_block_free_space,last_block, to_copy)); |
3124 | memcpy((uchar*) last_block + last_block->used, data, to_copy); |
3125 | last_block->used+=to_copy; |
3126 | } |
3127 | DBUG_RETURN(success); |
3128 | } |
3129 | |
3130 | |
3131 | my_bool Query_cache::write_result_data(Query_cache_block **result_block, |
3132 | size_t data_len, uchar* data, |
3133 | Query_cache_block *query_block, |
3134 | Query_cache_block::block_type type) |
3135 | { |
3136 | DBUG_ENTER("Query_cache::write_result_data" ); |
3137 | DBUG_PRINT("qcache" , ("data_len %zu" ,data_len)); |
3138 | |
3139 | /* |
3140 | Reserve block(s) for filling |
3141 | During data allocation we must have structure_guard_mutex locked. |
3142 | As data copy is not a fast operation, it's better if we don't have |
3143 | structure_guard_mutex locked during data coping. |
3144 | Thus we first allocate space and lock query, then unlock |
3145 | structure_guard_mutex and copy data. |
3146 | */ |
3147 | |
3148 | my_bool success = allocate_data_chain(result_block, data_len, query_block, |
3149 | type == Query_cache_block::RES_BEG); |
3150 | if (success) |
3151 | { |
3152 | // It is success (nobody can prevent us write data) |
3153 | unlock(); |
3154 | uint = (ALIGN_SIZE(sizeof(Query_cache_block)) + |
3155 | ALIGN_SIZE(sizeof(Query_cache_result))); |
3156 | #ifndef EMBEDDED_LIBRARY |
3157 | Query_cache_block *block= *result_block; |
3158 | uchar *rest= data; |
3159 | // Now fill list of blocks that created by allocate_data_chain |
3160 | do |
3161 | { |
3162 | block->type = type; |
3163 | size_t length = block->used - headers_len; |
3164 | DBUG_PRINT("qcache" , ("write %zu byte in block %p" ,length, |
3165 | block)); |
3166 | memcpy((uchar*) block+headers_len, rest, length); |
3167 | rest += length; |
3168 | block = block->next; |
3169 | type = Query_cache_block::RES_CONT; |
3170 | } while (block != *result_block); |
3171 | #else |
3172 | /* |
3173 | Set type of first block, emb_store_querycache_result() will handle |
3174 | the others. |
3175 | */ |
3176 | (*result_block)->type= type; |
3177 | Querycache_stream qs(*result_block, headers_len); |
3178 | emb_store_querycache_result(&qs, (THD*)data); |
3179 | #endif /*!EMBEDDED_LIBRARY*/ |
3180 | } |
3181 | else |
3182 | { |
3183 | if (*result_block != 0) |
3184 | { |
3185 | // Destroy list of blocks that was created & locked by lock_result_data |
3186 | Query_cache_block *block = *result_block; |
3187 | do |
3188 | { |
3189 | Query_cache_block *current = block; |
3190 | block = block->next; |
3191 | free_memory_block(current); |
3192 | } while (block != *result_block); |
3193 | *result_block = 0; |
3194 | /* |
3195 | It is not success => not unlock structure_guard_mutex (we need it to |
3196 | free query) |
3197 | */ |
3198 | } |
3199 | } |
3200 | DBUG_PRINT("qcache" , ("success %d" , (int) success)); |
3201 | DBUG_RETURN(success); |
3202 | } |
3203 | |
3204 | inline size_t Query_cache::get_min_first_result_data_size() |
3205 | { |
3206 | if (queries_in_cache < QUERY_CACHE_MIN_ESTIMATED_QUERIES_NUMBER) |
3207 | return min_result_data_size; |
3208 | size_t avg_result = (query_cache_size - free_memory) / queries_in_cache; |
3209 | avg_result = MY_MIN(avg_result, query_cache_limit); |
3210 | return MY_MAX(min_result_data_size, avg_result); |
3211 | } |
3212 | |
3213 | inline size_t Query_cache::get_min_append_result_data_size() |
3214 | { |
3215 | return min_result_data_size; |
3216 | } |
3217 | |
3218 | /* |
3219 | Allocate one or more blocks to hold data |
3220 | */ |
3221 | my_bool Query_cache::allocate_data_chain(Query_cache_block **result_block, |
3222 | size_t data_len, |
3223 | Query_cache_block *query_block, |
3224 | my_bool first_block_arg) |
3225 | { |
3226 | size_t = (ALIGN_SIZE(sizeof(Query_cache_block)) + |
3227 | ALIGN_SIZE(sizeof(Query_cache_result))); |
3228 | size_t min_size = (first_block_arg ? |
3229 | get_min_first_result_data_size(): |
3230 | get_min_append_result_data_size()); |
3231 | Query_cache_block *prev_block= NULL; |
3232 | Query_cache_block *new_block; |
3233 | DBUG_ENTER("Query_cache::allocate_data_chain" ); |
3234 | DBUG_PRINT("qcache" , ("data_len %zu, all_headers_len %zu" , |
3235 | data_len, all_headers_len)); |
3236 | |
3237 | do |
3238 | { |
3239 | size_t len= data_len + all_headers_len; |
3240 | size_t align_len= ALIGN_SIZE(len); |
3241 | |
3242 | if (!(new_block= allocate_block(MY_MAX(min_size, align_len), |
3243 | min_result_data_size == 0, |
3244 | all_headers_len + min_result_data_size))) |
3245 | { |
3246 | DBUG_PRINT("warning" , ("Can't allocate block for results" )); |
3247 | DBUG_RETURN(FALSE); |
3248 | } |
3249 | |
3250 | new_block->n_tables = 0; |
3251 | new_block->used = MY_MIN(len, new_block->length); |
3252 | new_block->type = Query_cache_block::RES_INCOMPLETE; |
3253 | new_block->next = new_block->prev = new_block; |
3254 | Query_cache_result * = new_block->result(); |
3255 | header->parent(query_block); |
3256 | |
3257 | DBUG_PRINT("qcache" , ("Block len %zu used %zu" , |
3258 | new_block->length, new_block->used)); |
3259 | |
3260 | if (prev_block) |
3261 | double_linked_list_join(prev_block, new_block); |
3262 | else |
3263 | *result_block= new_block; |
3264 | if (new_block->length >= len) |
3265 | break; |
3266 | |
3267 | /* |
3268 | We got less memory then we need (no big memory blocks) => |
3269 | Continue to allocated more blocks until we got everything we need. |
3270 | */ |
3271 | data_len= len - new_block->length; |
3272 | prev_block= new_block; |
3273 | } while (1); |
3274 | |
3275 | DBUG_RETURN(TRUE); |
3276 | } |
3277 | |
3278 | /***************************************************************************** |
3279 | Tables management |
3280 | *****************************************************************************/ |
3281 | |
3282 | /* |
3283 | Invalidate the first table in the table_list |
3284 | */ |
3285 | |
3286 | void Query_cache::invalidate_table(THD *thd, TABLE_LIST *table_list) |
3287 | { |
3288 | if (table_list->table != 0) |
3289 | invalidate_table(thd, table_list->table); // Table is open |
3290 | else |
3291 | { |
3292 | const char *key; |
3293 | uint key_length; |
3294 | key_length= get_table_def_key(table_list, &key); |
3295 | |
3296 | // We don't store temporary tables => no key_length+=4 ... |
3297 | invalidate_table(thd, (uchar *)key, key_length); |
3298 | } |
3299 | } |
3300 | |
3301 | void Query_cache::invalidate_table(THD *thd, TABLE *table) |
3302 | { |
3303 | invalidate_table(thd, (uchar*) table->s->table_cache_key.str, |
3304 | table->s->table_cache_key.length); |
3305 | } |
3306 | |
3307 | void Query_cache::invalidate_table(THD *thd, uchar * key, size_t key_length) |
3308 | { |
3309 | DEBUG_SYNC(thd, "wait_in_query_cache_invalidate1" ); |
3310 | |
3311 | /* |
3312 | Lock the query cache and queue all invalidation attempts to avoid |
3313 | the risk of a race between invalidation, cache inserts and flushes. |
3314 | */ |
3315 | lock(thd); |
3316 | |
3317 | DEBUG_SYNC(thd, "wait_in_query_cache_invalidate2" ); |
3318 | |
3319 | if (query_cache_size > 0) |
3320 | invalidate_table_internal(thd, key, key_length); |
3321 | |
3322 | unlock(); |
3323 | } |
3324 | |
3325 | |
3326 | /** |
3327 | Try to locate and invalidate a table by name. |
3328 | The caller must ensure that no other thread is trying to work with |
3329 | the query cache when this function is executed. |
3330 | |
3331 | @pre structure_guard_mutex is acquired or LOCKED is set. |
3332 | */ |
3333 | |
3334 | void |
3335 | Query_cache::invalidate_table_internal(THD *thd, uchar *key, size_t key_length) |
3336 | { |
3337 | Query_cache_block *table_block= |
3338 | (Query_cache_block*)my_hash_search(&tables, key, key_length); |
3339 | if (table_block) |
3340 | { |
3341 | Query_cache_block_table *list_root= table_block->table(0); |
3342 | invalidate_query_block_list(thd, list_root); |
3343 | } |
3344 | } |
3345 | |
3346 | /** |
3347 | Invalidate a linked list of query cache blocks. |
3348 | |
3349 | Each block tries to acquire a block level lock before |
3350 | free_query is a called. This function will in turn affect |
3351 | related table- and result-blocks. |
3352 | |
3353 | @param[in,out] thd Thread context. |
3354 | @param[in,out] list_root A pointer to a circular list of query blocks. |
3355 | |
3356 | */ |
3357 | |
3358 | void |
3359 | Query_cache::invalidate_query_block_list(THD *thd, |
3360 | Query_cache_block_table *list_root) |
3361 | { |
3362 | while (list_root->next != list_root) |
3363 | { |
3364 | Query_cache_block *query_block= list_root->next->block(); |
3365 | BLOCK_LOCK_WR(query_block); |
3366 | free_query(query_block); |
3367 | } |
3368 | } |
3369 | |
3370 | /* |
3371 | Register given table list beginning with given position in tables table of |
3372 | block |
3373 | |
3374 | SYNOPSIS |
3375 | Query_cache::register_tables_from_list |
3376 | thd thread handle |
3377 | tables_used given table list |
3378 | counter number current position in table of tables of block |
3379 | block_table pointer to current position in tables table of block |
3380 | |
3381 | RETURN |
3382 | 0 error |
3383 | number of next position of table entry in table of tables of block |
3384 | */ |
3385 | |
3386 | TABLE_COUNTER_TYPE |
3387 | Query_cache::register_tables_from_list(THD *thd, TABLE_LIST *tables_used, |
3388 | TABLE_COUNTER_TYPE counter, |
3389 | Query_cache_block_table **block_table) |
3390 | { |
3391 | TABLE_COUNTER_TYPE n; |
3392 | DBUG_ENTER("Query_cache::register_tables_from_list" ); |
3393 | for (n= counter; |
3394 | tables_used; |
3395 | tables_used= tables_used->next_global, n++, (*block_table)++) |
3396 | { |
3397 | if (tables_used->is_anonymous_derived_table()) |
3398 | { |
3399 | DBUG_PRINT("qcache" , ("derived table skipped" )); |
3400 | n--; |
3401 | (*block_table)--; |
3402 | continue; |
3403 | } |
3404 | (*block_table)->n= n; |
3405 | if (tables_used->view) |
3406 | { |
3407 | const char *key; |
3408 | uint key_length; |
3409 | DBUG_PRINT("qcache" , ("view: %s db: %s" , |
3410 | tables_used->view_name.str, |
3411 | tables_used->view_db.str)); |
3412 | key_length= get_table_def_key(tables_used, &key); |
3413 | /* |
3414 | There are not callback function for for VIEWs |
3415 | */ |
3416 | if (!insert_table(thd, key_length, key, (*block_table), |
3417 | tables_used->view_db.length, 0, |
3418 | HA_CACHE_TBL_NONTRANSACT, 0, 0, TRUE)) |
3419 | DBUG_RETURN(0); |
3420 | /* |
3421 | We do not need to register view tables here because they are already |
3422 | present in the global list. |
3423 | */ |
3424 | } |
3425 | else |
3426 | { |
3427 | DBUG_PRINT("qcache" , |
3428 | ("table: %s db: %s openinfo: %p keylen: %zu key: %p" , |
3429 | tables_used->table->s->table_name.str, |
3430 | tables_used->table->s->table_cache_key.str, |
3431 | tables_used->table, |
3432 | tables_used->table->s->table_cache_key.length, |
3433 | tables_used->table->s->table_cache_key.str)); |
3434 | |
3435 | if (!insert_table(thd, tables_used->table->s->table_cache_key.length, |
3436 | tables_used->table->s->table_cache_key.str, |
3437 | (*block_table), |
3438 | tables_used->db.length, 0, |
3439 | tables_used->table->file->table_cache_type(), |
3440 | tables_used->callback_func, |
3441 | tables_used->engine_data, |
3442 | TRUE)) |
3443 | DBUG_RETURN(0); |
3444 | |
3445 | if (tables_used->table->file-> |
3446 | register_query_cache_dependant_tables(thd, this, block_table, &n)) |
3447 | DBUG_RETURN(0); |
3448 | } |
3449 | } |
3450 | DBUG_RETURN(n - counter); |
3451 | } |
3452 | |
3453 | /* |
3454 | Store all used tables |
3455 | |
3456 | SYNOPSIS |
3457 | register_all_tables() |
3458 | thd Thread handle |
3459 | block Store tables in this block |
3460 | tables_used List if used tables |
3461 | tables_arg Not used ? |
3462 | */ |
3463 | |
3464 | my_bool Query_cache::register_all_tables(THD *thd, |
3465 | Query_cache_block *block, |
3466 | TABLE_LIST *tables_used, |
3467 | TABLE_COUNTER_TYPE tables_arg) |
3468 | { |
3469 | TABLE_COUNTER_TYPE n; |
3470 | DBUG_PRINT("qcache" , ("register tables block %p, n %d, header %x" , |
3471 | block, (int) tables_arg, |
3472 | (int) ALIGN_SIZE(sizeof(Query_cache_block)))); |
3473 | |
3474 | Query_cache_block_table *block_table = block->table(0); |
3475 | |
3476 | n= register_tables_from_list(thd, tables_used, 0, &block_table); |
3477 | |
3478 | if (n==0) |
3479 | { |
3480 | /* Unlink the tables we allocated above */ |
3481 | for (Query_cache_block_table *tmp = block->table(0) ; |
3482 | tmp != block_table; |
3483 | tmp++) |
3484 | unlink_table(tmp); |
3485 | if (block_table->parent) |
3486 | unlink_table(block_table); |
3487 | } |
3488 | return MY_TEST(n); |
3489 | } |
3490 | |
3491 | |
3492 | /** |
3493 | Insert used table name into the cache. |
3494 | |
3495 | @return Error status |
3496 | @retval FALSE On error |
3497 | @retval TRUE On success |
3498 | */ |
3499 | |
3500 | my_bool |
3501 | Query_cache::insert_table(THD *thd, size_t key_len, const char *key, |
3502 | Query_cache_block_table *node, size_t db_length, uint8 suffix_length_arg, |
3503 | uint8 cache_type, |
3504 | qc_engine_callback callback, |
3505 | ulonglong engine_data, |
3506 | my_bool hash) |
3507 | { |
3508 | DBUG_ENTER("Query_cache::insert_table" ); |
3509 | DBUG_PRINT("qcache" , ("insert table node %p, len %zu" , |
3510 | node, key_len)); |
3511 | |
3512 | Query_cache_block *table_block= |
3513 | (hash ? |
3514 | (Query_cache_block *) my_hash_search(&tables, (uchar*) key, key_len) : |
3515 | NULL); |
3516 | |
3517 | if (table_block && |
3518 | table_block->table()->engine_data() != engine_data) |
3519 | { |
3520 | DBUG_PRINT("qcache" , |
3521 | ("Handler require invalidation queries of %s.%s %llu-%llu" , |
3522 | table_block->table()->db(), |
3523 | table_block->table()->table(), |
3524 | engine_data, |
3525 | table_block->table()->engine_data())); |
3526 | /* |
3527 | as far as we delete all queries with this table, table block will be |
3528 | deleted, too |
3529 | */ |
3530 | { |
3531 | Query_cache_block_table *list_root= table_block->table(0); |
3532 | invalidate_query_block_list(thd, list_root); |
3533 | } |
3534 | |
3535 | table_block= 0; |
3536 | } |
3537 | |
3538 | if (table_block == 0) |
3539 | { |
3540 | DBUG_PRINT("qcache" , ("new table block from %p (%u)" , |
3541 | key, (int) key_len)); |
3542 | table_block= write_block_data(key_len, (uchar*) key, |
3543 | ALIGN_SIZE(sizeof(Query_cache_table)), |
3544 | Query_cache_block::TABLE, 1); |
3545 | if (table_block == 0) |
3546 | { |
3547 | DBUG_PRINT("qcache" , ("Can't write table name to cache" )); |
3548 | DBUG_RETURN(0); |
3549 | } |
3550 | Query_cache_table *= table_block->table(); |
3551 | double_linked_list_simple_include(table_block, |
3552 | &tables_blocks); |
3553 | /* |
3554 | First node in the Query_cache_block_table-chain is the table-type |
3555 | block. This block will only have one Query_cache_block_table (n=0). |
3556 | */ |
3557 | Query_cache_block_table *list_root= table_block->table(0); |
3558 | list_root->n= 0; |
3559 | |
3560 | /* |
3561 | The node list is circular in nature. |
3562 | */ |
3563 | list_root->next= list_root->prev= list_root; |
3564 | |
3565 | if (hash && |
3566 | my_hash_insert(&tables, (const uchar *) table_block)) |
3567 | { |
3568 | DBUG_PRINT("qcache" , ("Can't insert table to hash" )); |
3569 | // write_block_data return locked block |
3570 | free_memory_block(table_block); |
3571 | DBUG_RETURN(0); |
3572 | } |
3573 | char *db= header->db(); |
3574 | header->table(db + db_length + 1); |
3575 | header->key_length((uint32)key_len); |
3576 | header->suffix_length(suffix_length_arg); |
3577 | header->type(cache_type); |
3578 | header->callback(callback); |
3579 | header->engine_data(engine_data); |
3580 | header->set_hashed(hash); |
3581 | |
3582 | /* |
3583 | We insert this table without the assumption that it isn't refrenenced by |
3584 | any queries. |
3585 | */ |
3586 | header->m_cached_query_count= 0; |
3587 | } |
3588 | |
3589 | /* |
3590 | Table is now in the cache; link the table_block-node associated |
3591 | with the currently processed query into the chain of queries depending |
3592 | on the cached table. |
3593 | */ |
3594 | Query_cache_block_table *list_root= table_block->table(0); |
3595 | node->next= list_root->next; |
3596 | list_root->next= node; |
3597 | node->next->prev= node; |
3598 | node->prev= list_root; |
3599 | node->parent= table_block->table(); |
3600 | /* |
3601 | Increase the counter to keep track on how long this chain |
3602 | of queries is. |
3603 | */ |
3604 | Query_cache_table *table_block_data= table_block->table(); |
3605 | table_block_data->m_cached_query_count++; |
3606 | DBUG_RETURN(1); |
3607 | } |
3608 | |
3609 | |
3610 | void Query_cache::unlink_table(Query_cache_block_table *node) |
3611 | { |
3612 | DBUG_ENTER("Query_cache::unlink_table" ); |
3613 | node->prev->next= node->next; |
3614 | node->next->prev= node->prev; |
3615 | Query_cache_block_table *neighbour= node->next; |
3616 | Query_cache_table *table_block_data= node->parent; |
3617 | table_block_data->m_cached_query_count--; |
3618 | |
3619 | DBUG_ASSERT(table_block_data->m_cached_query_count >= 0); |
3620 | |
3621 | if (neighbour->next == neighbour) |
3622 | { |
3623 | DBUG_ASSERT(table_block_data->m_cached_query_count == 0); |
3624 | /* |
3625 | If neighbor is root of list, the list is empty. |
3626 | The root of the list is always a table-type block |
3627 | which contain exactly one Query_cache_block_table |
3628 | node object, thus we can use the block() method |
3629 | to calculate the Query_cache_block address. |
3630 | */ |
3631 | Query_cache_block *table_block= neighbour->block(); |
3632 | double_linked_list_exclude(table_block, |
3633 | &tables_blocks); |
3634 | Query_cache_table *= table_block->table(); |
3635 | if (header->is_hashed()) |
3636 | my_hash_delete(&tables,(uchar *) table_block); |
3637 | free_memory_block(table_block); |
3638 | } |
3639 | DBUG_VOID_RETURN; |
3640 | } |
3641 | |
3642 | /***************************************************************************** |
3643 | Free memory management |
3644 | *****************************************************************************/ |
3645 | |
3646 | Query_cache_block * |
3647 | Query_cache::allocate_block(size_t len, my_bool not_less, size_t min) |
3648 | { |
3649 | DBUG_ENTER("Query_cache::allocate_block" ); |
3650 | DBUG_PRINT("qcache" , ("len %zu, not less %d, min %zu" , |
3651 | len, not_less,min)); |
3652 | |
3653 | if (len >= MY_MIN(query_cache_size, query_cache_limit)) |
3654 | { |
3655 | DBUG_PRINT("qcache" , ("Query cache hase only %zu memory and limit %zu" , |
3656 | query_cache_size, query_cache_limit)); |
3657 | DBUG_RETURN(0); // in any case we don't have such piece of memory |
3658 | } |
3659 | |
3660 | /* Free old queries until we have enough memory to store this block */ |
3661 | Query_cache_block *block; |
3662 | do |
3663 | { |
3664 | block= get_free_block(len, not_less, min); |
3665 | } |
3666 | while (block == 0 && !free_old_query()); |
3667 | |
3668 | if (block != 0) // If we found a suitable block |
3669 | { |
3670 | if (block->length >= ALIGN_SIZE(len) + min_allocation_unit) |
3671 | split_block(block,ALIGN_SIZE(len)); |
3672 | } |
3673 | |
3674 | DBUG_RETURN(block); |
3675 | } |
3676 | |
3677 | |
3678 | Query_cache_block * |
3679 | Query_cache::get_free_block(size_t len, my_bool not_less, size_t min) |
3680 | { |
3681 | Query_cache_block *block = 0, *first = 0; |
3682 | DBUG_ENTER("Query_cache::get_free_block" ); |
3683 | DBUG_PRINT("qcache" ,("length %zu, not_less %d, min %zu" , len, |
3684 | (int)not_less, min)); |
3685 | |
3686 | /* Find block with minimal size > len */ |
3687 | uint start = find_bin(len); |
3688 | // try matching bin |
3689 | if (bins[start].number != 0) |
3690 | { |
3691 | Query_cache_block *list = bins[start].free_blocks; |
3692 | if (list->prev->length >= len) // check block with max size |
3693 | { |
3694 | first = list; |
3695 | uint n = 0; |
3696 | while ( n < QUERY_CACHE_MEM_BIN_TRY && |
3697 | first->length < len) //we don't need irst->next != list |
3698 | { |
3699 | first=first->next; |
3700 | n++; |
3701 | } |
3702 | if (first->length >= len) |
3703 | block=first; |
3704 | else // we don't need if (first->next != list) |
3705 | { |
3706 | n = 0; |
3707 | block = list->prev; |
3708 | while (n < QUERY_CACHE_MEM_BIN_TRY && |
3709 | block->length > len) |
3710 | { |
3711 | block=block->prev; |
3712 | n++; |
3713 | } |
3714 | if (block->length < len) |
3715 | block=block->next; |
3716 | } |
3717 | } |
3718 | else |
3719 | first = list->prev; |
3720 | } |
3721 | if (block == 0 && start > 0) |
3722 | { |
3723 | DBUG_PRINT("qcache" ,("Try bins with bigger block size" )); |
3724 | // Try more big bins |
3725 | int i = start - 1; |
3726 | while (i > 0 && bins[i].number == 0) |
3727 | i--; |
3728 | if (bins[i].number > 0) |
3729 | block = bins[i].free_blocks; |
3730 | } |
3731 | |
3732 | // If no big blocks => try less size (if it is possible) |
3733 | if (block == 0 && ! not_less) |
3734 | { |
3735 | DBUG_PRINT("qcache" ,("Try to allocate a smaller block" )); |
3736 | if (first != 0 && first->length > min) |
3737 | block = first; |
3738 | else |
3739 | { |
3740 | uint i = start + 1; |
3741 | /* bins[mem_bin_num].number contains 1 for easy end test */ |
3742 | for (i= start+1 ; bins[i].number == 0 ; i++) ; |
3743 | if (i < mem_bin_num && bins[i].free_blocks->prev->length >= min) |
3744 | block = bins[i].free_blocks->prev; |
3745 | } |
3746 | } |
3747 | if (block != 0) |
3748 | exclude_from_free_memory_list(block); |
3749 | |
3750 | DBUG_PRINT("qcache" ,("getting block %p" , block)); |
3751 | DBUG_RETURN(block); |
3752 | } |
3753 | |
3754 | |
3755 | void Query_cache::free_memory_block(Query_cache_block *block) |
3756 | { |
3757 | DBUG_ENTER("Query_cache::free_memory_block" ); |
3758 | block->used=0; |
3759 | block->type= Query_cache_block::FREE; // mark block as free in any case |
3760 | DBUG_PRINT("qcache" , |
3761 | ("first_block %p, block %p, pnext %p pprev %p" , |
3762 | first_block, block, block->pnext, |
3763 | block->pprev)); |
3764 | |
3765 | if (block->pnext != first_block && block->pnext->is_free()) |
3766 | block = join_free_blocks(block, block->pnext); |
3767 | if (block != first_block && block->pprev->is_free()) |
3768 | block = join_free_blocks(block->pprev, block->pprev); |
3769 | insert_into_free_memory_list(block); |
3770 | DBUG_VOID_RETURN; |
3771 | } |
3772 | |
3773 | |
3774 | void Query_cache::split_block(Query_cache_block *block, size_t len) |
3775 | { |
3776 | DBUG_ENTER("Query_cache::split_block" ); |
3777 | Query_cache_block *new_block = (Query_cache_block*)(((uchar*) block)+len); |
3778 | |
3779 | new_block->init(block->length - len); |
3780 | total_blocks++; |
3781 | block->length=len; |
3782 | new_block->pnext = block->pnext; |
3783 | block->pnext = new_block; |
3784 | new_block->pprev = block; |
3785 | new_block->pnext->pprev = new_block; |
3786 | |
3787 | if (block->type == Query_cache_block::FREE) |
3788 | { |
3789 | // if block was free then it already joined with all free neighbours |
3790 | insert_into_free_memory_list(new_block); |
3791 | } |
3792 | else |
3793 | free_memory_block(new_block); |
3794 | |
3795 | DBUG_PRINT("qcache" , ("split %p (%zu) new %p" , |
3796 | block, len, new_block)); |
3797 | DBUG_VOID_RETURN; |
3798 | } |
3799 | |
3800 | |
3801 | Query_cache_block * |
3802 | Query_cache::join_free_blocks(Query_cache_block *first_block_arg, |
3803 | Query_cache_block *block_in_list) |
3804 | { |
3805 | Query_cache_block *second_block; |
3806 | DBUG_ENTER("Query_cache::join_free_blocks" ); |
3807 | DBUG_PRINT("qcache" , |
3808 | ("join first %p, pnext %p, in list %p" , |
3809 | first_block_arg, first_block_arg->pnext, |
3810 | block_in_list)); |
3811 | |
3812 | exclude_from_free_memory_list(block_in_list); |
3813 | second_block = first_block_arg->pnext; |
3814 | // May be was not free block |
3815 | second_block->used=0; |
3816 | second_block->destroy(); |
3817 | total_blocks--; |
3818 | |
3819 | first_block_arg->length += second_block->length; |
3820 | first_block_arg->pnext = second_block->pnext; |
3821 | second_block->pnext->pprev = first_block_arg; |
3822 | |
3823 | DBUG_RETURN(first_block_arg); |
3824 | } |
3825 | |
3826 | |
3827 | my_bool Query_cache::append_next_free_block(Query_cache_block *block, |
3828 | size_t add_size) |
3829 | { |
3830 | Query_cache_block *next_block = block->pnext; |
3831 | DBUG_ENTER("Query_cache::append_next_free_block" ); |
3832 | DBUG_PRINT("enter" , ("block %p, add_size %zu" , block, |
3833 | add_size)); |
3834 | |
3835 | if (next_block != first_block && next_block->is_free()) |
3836 | { |
3837 | size_t old_len = block->length; |
3838 | exclude_from_free_memory_list(next_block); |
3839 | next_block->destroy(); |
3840 | total_blocks--; |
3841 | |
3842 | block->length += next_block->length; |
3843 | block->pnext = next_block->pnext; |
3844 | next_block->pnext->pprev = block; |
3845 | |
3846 | if (block->length > ALIGN_SIZE(old_len + add_size) + min_allocation_unit) |
3847 | split_block(block,ALIGN_SIZE(old_len + add_size)); |
3848 | DBUG_PRINT("exit" , ("block was appended" )); |
3849 | DBUG_RETURN(1); |
3850 | } |
3851 | DBUG_RETURN(0); |
3852 | } |
3853 | |
3854 | |
3855 | void Query_cache::exclude_from_free_memory_list(Query_cache_block *free_block) |
3856 | { |
3857 | DBUG_ENTER("Query_cache::exclude_from_free_memory_list" ); |
3858 | Query_cache_memory_bin *bin = *((Query_cache_memory_bin **) |
3859 | free_block->data()); |
3860 | double_linked_list_exclude(free_block, &bin->free_blocks); |
3861 | bin->number--; |
3862 | free_memory-=free_block->length; |
3863 | free_memory_blocks--; |
3864 | DBUG_PRINT("qcache" ,("exclude block %p, bin %p" , free_block, |
3865 | bin)); |
3866 | DBUG_VOID_RETURN; |
3867 | } |
3868 | |
3869 | void Query_cache::insert_into_free_memory_list(Query_cache_block *free_block) |
3870 | { |
3871 | DBUG_ENTER("Query_cache::insert_into_free_memory_list" ); |
3872 | uint idx = find_bin(free_block->length); |
3873 | insert_into_free_memory_sorted_list(free_block, &bins[idx].free_blocks); |
3874 | /* |
3875 | We have enough memory in block for storing bin reference due to |
3876 | min_allocation_unit choice |
3877 | */ |
3878 | Query_cache_memory_bin **bin_ptr = ((Query_cache_memory_bin**) |
3879 | free_block->data()); |
3880 | *bin_ptr = bins+idx; |
3881 | (*bin_ptr)->number++; |
3882 | DBUG_PRINT("qcache" ,("insert block %p, bin[%d] %p" , |
3883 | free_block, idx, *bin_ptr)); |
3884 | DBUG_VOID_RETURN; |
3885 | } |
3886 | |
3887 | uint Query_cache::find_bin(size_t size) |
3888 | { |
3889 | DBUG_ENTER("Query_cache::find_bin" ); |
3890 | // Binary search |
3891 | size_t left = 0, right = mem_bin_steps; |
3892 | do |
3893 | { |
3894 | size_t middle = (left + right) / 2; |
3895 | if (steps[middle].size > size) |
3896 | left = middle+1; |
3897 | else |
3898 | right = middle; |
3899 | } while (left < right); |
3900 | if (left == 0) |
3901 | { |
3902 | // first bin not subordinate of common rules |
3903 | DBUG_PRINT("qcache" , ("first bin (# 0), size %zu" ,size)); |
3904 | DBUG_RETURN(0); |
3905 | } |
3906 | size_t bin = steps[left].idx - |
3907 | ((size - steps[left].size)/steps[left].increment); |
3908 | |
3909 | DBUG_PRINT("qcache" , ("bin %zu step %zu, size %zu step size %zu" , |
3910 | bin, left, size, steps[left].size)); |
3911 | DBUG_RETURN((uint)bin); |
3912 | } |
3913 | |
3914 | |
3915 | /***************************************************************************** |
3916 | Lists management |
3917 | *****************************************************************************/ |
3918 | |
3919 | void Query_cache::move_to_query_list_end(Query_cache_block *query_block) |
3920 | { |
3921 | DBUG_ENTER("Query_cache::move_to_query_list_end" ); |
3922 | double_linked_list_exclude(query_block, &queries_blocks); |
3923 | double_linked_list_simple_include(query_block, &queries_blocks); |
3924 | DBUG_VOID_RETURN; |
3925 | } |
3926 | |
3927 | |
3928 | void Query_cache::insert_into_free_memory_sorted_list(Query_cache_block * |
3929 | new_block, |
3930 | Query_cache_block ** |
3931 | list) |
3932 | { |
3933 | DBUG_ENTER("Query_cache::insert_into_free_memory_sorted_list" ); |
3934 | /* |
3935 | list sorted by size in ascendant order, because we need small blocks |
3936 | more frequently than bigger ones |
3937 | */ |
3938 | |
3939 | new_block->used = 0; |
3940 | new_block->n_tables = 0; |
3941 | new_block->type = Query_cache_block::FREE; |
3942 | |
3943 | if (*list == 0) |
3944 | { |
3945 | *list = new_block->next=new_block->prev=new_block; |
3946 | DBUG_PRINT("qcache" , ("inserted into empty list" )); |
3947 | } |
3948 | else |
3949 | { |
3950 | Query_cache_block *point = *list; |
3951 | if (point->length >= new_block->length) |
3952 | { |
3953 | point = point->prev; |
3954 | *list = new_block; |
3955 | } |
3956 | else |
3957 | { |
3958 | /* Find right position in sorted list to put block */ |
3959 | while (point->next != *list && |
3960 | point->next->length < new_block->length) |
3961 | point=point->next; |
3962 | } |
3963 | new_block->prev = point; |
3964 | new_block->next = point->next; |
3965 | new_block->next->prev = new_block; |
3966 | point->next = new_block; |
3967 | } |
3968 | free_memory+=new_block->length; |
3969 | free_memory_blocks++; |
3970 | DBUG_VOID_RETURN; |
3971 | } |
3972 | |
3973 | |
3974 | void |
3975 | Query_cache::double_linked_list_simple_include(Query_cache_block *point, |
3976 | Query_cache_block ** |
3977 | list_pointer) |
3978 | { |
3979 | DBUG_ENTER("Query_cache::double_linked_list_simple_include" ); |
3980 | DBUG_PRINT("qcache" , ("including block %p" , point)); |
3981 | if (*list_pointer == 0) |
3982 | *list_pointer=point->next=point->prev=point; |
3983 | else |
3984 | { |
3985 | // insert to the end of list |
3986 | point->next = (*list_pointer); |
3987 | point->prev = (*list_pointer)->prev; |
3988 | point->prev->next = point; |
3989 | (*list_pointer)->prev = point; |
3990 | } |
3991 | DBUG_VOID_RETURN; |
3992 | } |
3993 | |
3994 | void |
3995 | Query_cache::double_linked_list_exclude(Query_cache_block *point, |
3996 | Query_cache_block **list_pointer) |
3997 | { |
3998 | DBUG_ENTER("Query_cache::double_linked_list_exclude" ); |
3999 | DBUG_PRINT("qcache" , ("excluding block %p, list %p" , |
4000 | point, list_pointer)); |
4001 | if (point->next == point) |
4002 | *list_pointer = 0; // empty list |
4003 | else |
4004 | { |
4005 | point->next->prev = point->prev; |
4006 | point->prev->next = point->next; |
4007 | /* |
4008 | If the root is removed; select a new root |
4009 | */ |
4010 | if (point == *list_pointer) |
4011 | *list_pointer= point->next; |
4012 | } |
4013 | DBUG_VOID_RETURN; |
4014 | } |
4015 | |
4016 | |
4017 | void Query_cache::double_linked_list_join(Query_cache_block *head_tail, |
4018 | Query_cache_block *tail_head) |
4019 | { |
4020 | Query_cache_block *head_head = head_tail->next, |
4021 | *tail_tail = tail_head->prev; |
4022 | head_head->prev = tail_tail; |
4023 | head_tail->next = tail_head; |
4024 | tail_head->prev = head_tail; |
4025 | tail_tail->next = head_head; |
4026 | } |
4027 | |
4028 | /***************************************************************************** |
4029 | Query |
4030 | *****************************************************************************/ |
4031 | |
4032 | /* |
4033 | Collect information about table types, check that tables are cachable and |
4034 | count them |
4035 | |
4036 | SYNOPSIS |
4037 | process_and_count_tables() |
4038 | tables_used table list for processing |
4039 | tables_type pointer to variable for table types collection |
4040 | |
4041 | RETURN |
4042 | 0 error |
4043 | >0 number of tables |
4044 | */ |
4045 | |
4046 | TABLE_COUNTER_TYPE |
4047 | Query_cache::process_and_count_tables(THD *thd, TABLE_LIST *tables_used, |
4048 | uint8 *tables_type) |
4049 | { |
4050 | DBUG_ENTER("process_and_count_tables" ); |
4051 | TABLE_COUNTER_TYPE table_count = 0; |
4052 | for (; tables_used; tables_used= tables_used->next_global) |
4053 | { |
4054 | table_count++; |
4055 | #ifndef NO_EMBEDDED_ACCESS_CHECKS |
4056 | /* |
4057 | Disable any attempt to store this statement if there are |
4058 | column level grants on any referenced tables. |
4059 | The grant.want_privileges flag was set to 1 in the |
4060 | check_grant() function earlier if the TABLE_LIST object |
4061 | had any associated column privileges. |
4062 | |
4063 | We need to check that the TABLE_LIST object isn't part |
4064 | of a VIEW definition because we want to be able to cache |
4065 | views. |
4066 | |
4067 | TODO: Although it is possible to cache views, the privilege |
4068 | check on view tables always fall back on column privileges |
4069 | even if there are more generic table privileges. Thus it isn't |
4070 | currently possible to retrieve cached view-tables unless the |
4071 | client has the super user privileges. |
4072 | */ |
4073 | if (tables_used->grant.want_privilege && |
4074 | tables_used->belong_to_view == NULL) |
4075 | { |
4076 | DBUG_PRINT("qcache" , ("Don't cache statement as it refers to " |
4077 | "tables with column privileges." )); |
4078 | thd->query_cache_is_applicable= 0; // Query can't be cached |
4079 | thd->lex->safe_to_cache_query= 0; // For prepared statements |
4080 | DBUG_RETURN(0); |
4081 | } |
4082 | #endif |
4083 | if (tables_used->view) |
4084 | { |
4085 | DBUG_PRINT("qcache" , ("view: %s db: %s" , |
4086 | tables_used->view_name.str, |
4087 | tables_used->view_db.str)); |
4088 | *tables_type|= HA_CACHE_TBL_NONTRANSACT; |
4089 | continue; |
4090 | } |
4091 | if (tables_used->derived) |
4092 | { |
4093 | DBUG_PRINT("qcache" , ("table: %s" , tables_used->alias.str)); |
4094 | table_count--; |
4095 | DBUG_PRINT("qcache" , ("derived table skipped" )); |
4096 | continue; |
4097 | } |
4098 | |
4099 | DBUG_PRINT("qcache" , ("table: %s db: %s type: %u" , |
4100 | tables_used->table->s->table_name.str, |
4101 | tables_used->table->s->db.str, |
4102 | tables_used->table->s->db_type()->db_type)); |
4103 | *tables_type|= tables_used->table->file->table_cache_type(); |
4104 | |
4105 | /* |
4106 | table_alias_charset used here because it depends of |
4107 | lower_case_table_names variable |
4108 | */ |
4109 | table_count+= tables_used->table->file-> |
4110 | count_query_cache_dependant_tables(tables_type); |
4111 | |
4112 | if (tables_used->table->s->not_usable_by_query_cache) |
4113 | { |
4114 | DBUG_PRINT("qcache" , |
4115 | ("select not cacheable: temporary, system or " |
4116 | "other non-cacheable table(s)" )); |
4117 | DBUG_RETURN(0); |
4118 | } |
4119 | } |
4120 | DBUG_RETURN(table_count); |
4121 | } |
4122 | |
4123 | |
4124 | /* |
4125 | In non-embedded QC intercepts result in net_real_write |
4126 | but if we have no net.vio then net_real_write |
4127 | will not be called, so QC can't get results of the query |
4128 | */ |
4129 | #ifdef EMBEDDED_LIBRARY |
4130 | #define qc_is_able_to_intercept_result(T) 1 |
4131 | #else |
4132 | #define qc_is_able_to_intercept_result(T) ((T)->net.vio) |
4133 | #endif |
4134 | |
4135 | |
4136 | /* |
4137 | If query is cacheable return number tables in query |
4138 | (query without tables are not cached) |
4139 | */ |
4140 | |
4141 | TABLE_COUNTER_TYPE |
4142 | Query_cache::is_cacheable(THD *thd, LEX *lex, |
4143 | TABLE_LIST *tables_used, uint8 *tables_type) |
4144 | { |
4145 | TABLE_COUNTER_TYPE table_count; |
4146 | DBUG_ENTER("Query_cache::is_cacheable" ); |
4147 | |
4148 | if (thd->lex->safe_to_cache_query && |
4149 | (thd->variables.query_cache_type == 1 || |
4150 | (thd->variables.query_cache_type == 2 && (lex->select_lex.options & |
4151 | OPTION_TO_QUERY_CACHE))) && |
4152 | qc_is_able_to_intercept_result(thd)) |
4153 | { |
4154 | DBUG_PRINT("qcache" , ("options: %lx %lx type: %u" , |
4155 | (long) OPTION_TO_QUERY_CACHE, |
4156 | (long) lex->select_lex.options, |
4157 | (int) thd->variables.query_cache_type)); |
4158 | |
4159 | if (!(table_count= process_and_count_tables(thd, tables_used, |
4160 | tables_type))) |
4161 | DBUG_RETURN(0); |
4162 | |
4163 | if (thd->in_multi_stmt_transaction_mode() && |
4164 | ((*tables_type)&HA_CACHE_TBL_TRANSACT)) |
4165 | { |
4166 | DBUG_PRINT("qcache" , ("not in autocommin mode" )); |
4167 | DBUG_RETURN(0); |
4168 | } |
4169 | DBUG_PRINT("qcache" , ("select is using %d tables" , table_count)); |
4170 | DBUG_RETURN(table_count); |
4171 | } |
4172 | |
4173 | DBUG_PRINT("qcache" , |
4174 | ("not interesting query: %d or not cacheable, options %lx %lx type: %u net->vio present: %u" , |
4175 | (int) lex->sql_command, |
4176 | (long) OPTION_TO_QUERY_CACHE, |
4177 | (long) lex->select_lex.options, |
4178 | (int) thd->variables.query_cache_type, |
4179 | (uint) MY_TEST(qc_is_able_to_intercept_result(thd)))); |
4180 | DBUG_RETURN(0); |
4181 | } |
4182 | |
4183 | /* |
4184 | Check handler allowance to cache query with these tables |
4185 | |
4186 | SYNOPSYS |
4187 | Query_cache::ask_handler_allowance() |
4188 | thd - thread handlers |
4189 | tables_used - tables list used in query |
4190 | |
4191 | RETURN |
4192 | 0 - caching allowed |
4193 | 1 - caching disallowed |
4194 | */ |
4195 | my_bool Query_cache::ask_handler_allowance(THD *thd, |
4196 | TABLE_LIST *tables_used) |
4197 | { |
4198 | DBUG_ENTER("Query_cache::ask_handler_allowance" ); |
4199 | |
4200 | for (; tables_used; tables_used= tables_used->next_global) |
4201 | { |
4202 | TABLE *table; |
4203 | handler *handler; |
4204 | if (!(table= tables_used->table)) |
4205 | continue; |
4206 | handler= table->file; |
4207 | if (!handler->register_query_cache_table(thd, |
4208 | table->s->normalized_path.str, |
4209 | (uint)table->s->normalized_path.length, |
4210 | &tables_used->callback_func, |
4211 | &tables_used->engine_data)) |
4212 | { |
4213 | DBUG_PRINT("qcache" , ("Handler does not allow caching for %s" , |
4214 | table->s->normalized_path.str)); |
4215 | /* |
4216 | As this can change from call to call, don't reset set |
4217 | thd->lex->safe_to_cache_query |
4218 | */ |
4219 | thd->query_cache_is_applicable= 0; // Query can't be cached |
4220 | DBUG_RETURN(1); |
4221 | } |
4222 | } |
4223 | DBUG_RETURN(0); |
4224 | } |
4225 | |
4226 | |
4227 | /***************************************************************************** |
4228 | Packing |
4229 | *****************************************************************************/ |
4230 | |
4231 | |
4232 | /** |
4233 | Rearrange all memory blocks so that free memory joins at the |
4234 | 'bottom' of the allocated memory block containing all cache data. |
4235 | @see Query_cache::pack(size_t join_limit, uint iteration_limit) |
4236 | */ |
4237 | |
4238 | void Query_cache::pack_cache() |
4239 | { |
4240 | DBUG_ENTER("Query_cache::pack_cache" ); |
4241 | |
4242 | DBUG_EXECUTE("check_querycache" ,query_cache.check_integrity(1);); |
4243 | |
4244 | uchar *border = 0; |
4245 | Query_cache_block *before = 0; |
4246 | size_t gap = 0; |
4247 | my_bool ok = 1; |
4248 | Query_cache_block *block = first_block; |
4249 | DUMP(this); |
4250 | |
4251 | if (first_block) |
4252 | { |
4253 | do |
4254 | { |
4255 | Query_cache_block *next=block->pnext; |
4256 | ok = move_by_type(&border, &before, &gap, block); |
4257 | block = next; |
4258 | } while (ok && block != first_block); |
4259 | |
4260 | if (border != 0) |
4261 | { |
4262 | Query_cache_block *new_block = (Query_cache_block *) border; |
4263 | new_block->init(gap); |
4264 | total_blocks++; |
4265 | new_block->pnext = before->pnext; |
4266 | before->pnext = new_block; |
4267 | new_block->pprev = before; |
4268 | new_block->pnext->pprev = new_block; |
4269 | insert_into_free_memory_list(new_block); |
4270 | } |
4271 | DUMP(this); |
4272 | } |
4273 | |
4274 | DBUG_EXECUTE("check_querycache" ,query_cache.check_integrity(1);); |
4275 | DBUG_VOID_RETURN; |
4276 | } |
4277 | |
4278 | |
4279 | my_bool Query_cache::move_by_type(uchar **border, |
4280 | Query_cache_block **before, size_t *gap, |
4281 | Query_cache_block *block) |
4282 | { |
4283 | DBUG_ENTER("Query_cache::move_by_type" ); |
4284 | |
4285 | my_bool ok = 1; |
4286 | switch (block->type) { |
4287 | case Query_cache_block::FREE: |
4288 | { |
4289 | DBUG_PRINT("qcache" , ("block %p FREE" , block)); |
4290 | if (*border == 0) |
4291 | { |
4292 | *border = (uchar *) block; |
4293 | *before = block->pprev; |
4294 | DBUG_PRINT("qcache" , ("gap beginning here" )); |
4295 | } |
4296 | exclude_from_free_memory_list(block); |
4297 | *gap +=block->length; |
4298 | block->pprev->pnext=block->pnext; |
4299 | block->pnext->pprev=block->pprev; |
4300 | block->destroy(); |
4301 | total_blocks--; |
4302 | DBUG_PRINT("qcache" , ("added to gap (%zu)" , *gap)); |
4303 | break; |
4304 | } |
4305 | case Query_cache_block::TABLE: |
4306 | { |
4307 | HASH_SEARCH_STATE record_idx; |
4308 | DBUG_PRINT("qcache" , ("block %p TABLE" , block)); |
4309 | if (*border == 0) |
4310 | break; |
4311 | size_t len = block->length, used = block->used; |
4312 | Query_cache_block_table *list_root = block->table(0); |
4313 | Query_cache_block_table *tprev = list_root->prev, |
4314 | *tnext = list_root->next; |
4315 | Query_cache_block *prev = block->prev, |
4316 | *next = block->next, |
4317 | *pprev = block->pprev, |
4318 | *pnext = block->pnext, |
4319 | *new_block =(Query_cache_block *) *border; |
4320 | size_t tablename_offset = block->table()->table() - block->table()->db(); |
4321 | char *data = (char*) block->data(); |
4322 | uchar *key; |
4323 | size_t key_length; |
4324 | key=query_cache_table_get_key((uchar*) block, &key_length, 0); |
4325 | my_hash_first(&tables, (uchar*) key, key_length, &record_idx); |
4326 | |
4327 | block->destroy(); |
4328 | new_block->init(len); |
4329 | new_block->type=Query_cache_block::TABLE; |
4330 | new_block->used=used; |
4331 | new_block->n_tables=1; |
4332 | memmove((char*) new_block->data(), data, len-new_block->headers_len()); |
4333 | relink(block, new_block, next, prev, pnext, pprev); |
4334 | if (tables_blocks == block) |
4335 | tables_blocks = new_block; |
4336 | |
4337 | Query_cache_block_table *nlist_root = new_block->table(0); |
4338 | nlist_root->n = 0; |
4339 | nlist_root->next = tnext; |
4340 | tnext->prev = nlist_root; |
4341 | nlist_root->prev = tprev; |
4342 | tprev->next = nlist_root; |
4343 | DBUG_PRINT("qcache" , |
4344 | ("list_root: %p tnext %p tprev %p tprev->next %p tnext->prev %p" , |
4345 | list_root, tnext, tprev, |
4346 | tprev->next,tnext->prev)); |
4347 | /* |
4348 | Go through all queries that uses this table and change them to |
4349 | point to the new table object |
4350 | */ |
4351 | Query_cache_table *new_block_table=new_block->table(); |
4352 | for (;tnext != nlist_root; tnext=tnext->next) |
4353 | tnext->parent= new_block_table; |
4354 | *border += len; |
4355 | *before = new_block; |
4356 | /* Fix pointer to table name */ |
4357 | new_block->table()->table(new_block->table()->db() + tablename_offset); |
4358 | /* Fix hash to point at moved block */ |
4359 | my_hash_replace(&tables, &record_idx, (uchar*) new_block); |
4360 | |
4361 | DBUG_PRINT("qcache" , ("moved %zu bytes to %p, new gap at %p" , |
4362 | len, new_block, *border)); |
4363 | break; |
4364 | } |
4365 | case Query_cache_block::QUERY: |
4366 | { |
4367 | HASH_SEARCH_STATE record_idx; |
4368 | DBUG_PRINT("qcache" , ("block %p QUERY" , block)); |
4369 | if (*border == 0) |
4370 | break; |
4371 | BLOCK_LOCK_WR(block); |
4372 | size_t len = block->length, used = block->used; |
4373 | TABLE_COUNTER_TYPE n_tables = block->n_tables; |
4374 | Query_cache_block *prev = block->prev, |
4375 | *next = block->next, |
4376 | *pprev = block->pprev, |
4377 | *pnext = block->pnext, |
4378 | *new_block =(Query_cache_block*) *border; |
4379 | char *data = (char*) block->data(); |
4380 | Query_cache_block *first_result_block = ((Query_cache_query *) |
4381 | block->data())->result(); |
4382 | uchar *key; |
4383 | size_t key_length; |
4384 | key=query_cache_query_get_key((uchar*) block, &key_length, 0); |
4385 | my_hash_first(&queries, (uchar*) key, key_length, &record_idx); |
4386 | block->query()->unlock_n_destroy(); |
4387 | block->destroy(); |
4388 | // Move table of used tables |
4389 | memmove((char*) new_block->table(0), (char*) block->table(0), |
4390 | ALIGN_SIZE(n_tables*sizeof(Query_cache_block_table))); |
4391 | new_block->init(len); |
4392 | new_block->type=Query_cache_block::QUERY; |
4393 | new_block->used=used; |
4394 | new_block->n_tables=n_tables; |
4395 | memmove((char*) new_block->data(), data, len - new_block->headers_len()); |
4396 | relink(block, new_block, next, prev, pnext, pprev); |
4397 | if (queries_blocks == block) |
4398 | queries_blocks = new_block; |
4399 | Query_cache_block_table *beg_of_table_table= block->table(0), |
4400 | *end_of_table_table= block->table(n_tables); |
4401 | uchar *beg_of_new_table_table= (uchar*) new_block->table(0); |
4402 | |
4403 | for (TABLE_COUNTER_TYPE j=0; j < n_tables; j++) |
4404 | { |
4405 | Query_cache_block_table *block_table = new_block->table(j); |
4406 | |
4407 | // use aligment from beginning of table if 'next' is in same block |
4408 | if ((beg_of_table_table <= block_table->next) && |
4409 | (block_table->next < end_of_table_table)) |
4410 | ((Query_cache_block_table *)(beg_of_new_table_table + |
4411 | (((uchar*)block_table->next) - |
4412 | ((uchar*)beg_of_table_table))))->prev= |
4413 | block_table; |
4414 | else |
4415 | block_table->next->prev= block_table; |
4416 | |
4417 | // use aligment from beginning of table if 'prev' is in same block |
4418 | if ((beg_of_table_table <= block_table->prev) && |
4419 | (block_table->prev < end_of_table_table)) |
4420 | ((Query_cache_block_table *)(beg_of_new_table_table + |
4421 | (((uchar*)block_table->prev) - |
4422 | ((uchar*)beg_of_table_table))))->next= |
4423 | block_table; |
4424 | else |
4425 | block_table->prev->next = block_table; |
4426 | } |
4427 | DBUG_PRINT("qcache" , ("after circle tt" )); |
4428 | *border += len; |
4429 | *before = new_block; |
4430 | new_block->query()->result(first_result_block); |
4431 | if (first_result_block != 0) |
4432 | { |
4433 | Query_cache_block *result_block = first_result_block; |
4434 | do |
4435 | { |
4436 | result_block->result()->parent(new_block); |
4437 | result_block = result_block->next; |
4438 | } while ( result_block != first_result_block ); |
4439 | } |
4440 | Query_cache_query *new_query= ((Query_cache_query *) new_block->data()); |
4441 | mysql_rwlock_init(key_rwlock_query_cache_query_lock, &new_query->lock); |
4442 | |
4443 | /* |
4444 | If someone is writing to this block, inform the writer that the block |
4445 | has been moved. |
4446 | */ |
4447 | Query_cache_tls *query_cache_tls= new_block->query()->writer(); |
4448 | if (query_cache_tls != NULL) |
4449 | { |
4450 | query_cache_tls->first_query_block= new_block; |
4451 | } |
4452 | /* Fix hash to point at moved block */ |
4453 | my_hash_replace(&queries, &record_idx, (uchar*) new_block); |
4454 | DBUG_PRINT("qcache" , ("moved %zu bytes to %p, new gap at %p" , |
4455 | len, new_block, *border)); |
4456 | break; |
4457 | } |
4458 | case Query_cache_block::RES_INCOMPLETE: |
4459 | case Query_cache_block::RES_BEG: |
4460 | case Query_cache_block::RES_CONT: |
4461 | case Query_cache_block::RESULT: |
4462 | { |
4463 | DBUG_PRINT("qcache" , ("block %p RES* (%d)" , block, |
4464 | (int) block->type)); |
4465 | if (*border == 0) |
4466 | break; |
4467 | Query_cache_block *query_block= block->result()->parent(); |
4468 | BLOCK_LOCK_WR(query_block); |
4469 | Query_cache_block *next= block->next, *prev= block->prev; |
4470 | Query_cache_block::block_type type= block->type; |
4471 | size_t len = block->length, used = block->used; |
4472 | Query_cache_block *pprev = block->pprev, |
4473 | *pnext = block->pnext, |
4474 | *new_block =(Query_cache_block*) *border; |
4475 | char *data = (char*) block->data(); |
4476 | block->destroy(); |
4477 | new_block->init(len); |
4478 | new_block->type=type; |
4479 | new_block->used=used; |
4480 | memmove((char*) new_block->data(), data, len - new_block->headers_len()); |
4481 | relink(block, new_block, next, prev, pnext, pprev); |
4482 | new_block->result()->parent(query_block); |
4483 | Query_cache_query *query = query_block->query(); |
4484 | if (query->result() == block) |
4485 | query->result(new_block); |
4486 | *border += len; |
4487 | *before = new_block; |
4488 | /* If result writing complete && we have free space in block */ |
4489 | size_t free_space= new_block->length - new_block->used; |
4490 | free_space-= free_space % ALIGN_SIZE(1); |
4491 | if (query->result()->type == Query_cache_block::RESULT && |
4492 | new_block->length > new_block->used && |
4493 | *gap + free_space > min_allocation_unit && |
4494 | new_block->length - free_space > min_allocation_unit) |
4495 | { |
4496 | *border-= free_space; |
4497 | *gap+= free_space; |
4498 | DBUG_PRINT("qcache" , |
4499 | ("rest of result free space added to gap (%zu)" , *gap)); |
4500 | new_block->length -= free_space; |
4501 | } |
4502 | BLOCK_UNLOCK_WR(query_block); |
4503 | DBUG_PRINT("qcache" , ("moved %zu bytes to %p, new gap at %p" , |
4504 | len, new_block, *border)); |
4505 | break; |
4506 | } |
4507 | default: |
4508 | DBUG_PRINT("error" , ("unexpected block type %d, block %p" , |
4509 | (int)block->type, block)); |
4510 | ok = 0; |
4511 | } |
4512 | DBUG_RETURN(ok); |
4513 | } |
4514 | |
4515 | |
4516 | void Query_cache::relink(Query_cache_block *oblock, |
4517 | Query_cache_block *nblock, |
4518 | Query_cache_block *next, Query_cache_block *prev, |
4519 | Query_cache_block *pnext, Query_cache_block *pprev) |
4520 | { |
4521 | if (prev == oblock) //check pointer to himself |
4522 | { |
4523 | nblock->prev = nblock; |
4524 | nblock->next = nblock; |
4525 | } |
4526 | else |
4527 | { |
4528 | nblock->prev = prev; |
4529 | prev->next=nblock; |
4530 | } |
4531 | if (next != oblock) |
4532 | { |
4533 | nblock->next = next; |
4534 | next->prev=nblock; |
4535 | } |
4536 | nblock->pprev = pprev; // Physical pointer to himself have only 1 free block |
4537 | nblock->pnext = pnext; |
4538 | pprev->pnext=nblock; |
4539 | pnext->pprev=nblock; |
4540 | } |
4541 | |
4542 | |
4543 | my_bool Query_cache::join_results(size_t join_limit) |
4544 | { |
4545 | my_bool has_moving = 0; |
4546 | DBUG_ENTER("Query_cache::join_results" ); |
4547 | |
4548 | if (queries_blocks != 0) |
4549 | { |
4550 | DBUG_ASSERT(query_cache_size > 0); |
4551 | Query_cache_block *block = queries_blocks; |
4552 | do |
4553 | { |
4554 | Query_cache_query * = block->query(); |
4555 | if (header->result() != 0 && |
4556 | header->result()->type == Query_cache_block::RESULT && |
4557 | header->length() > join_limit) |
4558 | { |
4559 | Query_cache_block *new_result_block = |
4560 | get_free_block(ALIGN_SIZE(header->length()) + |
4561 | ALIGN_SIZE(sizeof(Query_cache_block)) + |
4562 | ALIGN_SIZE(sizeof(Query_cache_result)), 1, 0); |
4563 | if (new_result_block != 0) |
4564 | { |
4565 | has_moving = 1; |
4566 | Query_cache_block *first_result = header->result(); |
4567 | size_t new_len = (header->length() + |
4568 | ALIGN_SIZE(sizeof(Query_cache_block)) + |
4569 | ALIGN_SIZE(sizeof(Query_cache_result))); |
4570 | if (new_result_block->length > |
4571 | ALIGN_SIZE(new_len) + min_allocation_unit) |
4572 | split_block(new_result_block, ALIGN_SIZE(new_len)); |
4573 | BLOCK_LOCK_WR(block); |
4574 | header->result(new_result_block); |
4575 | new_result_block->type = Query_cache_block::RESULT; |
4576 | new_result_block->n_tables = 0; |
4577 | new_result_block->used = new_len; |
4578 | |
4579 | new_result_block->next = new_result_block->prev = new_result_block; |
4580 | DBUG_PRINT("qcache" , ("new block %zu/%zu (%zu)" , |
4581 | new_result_block->length, |
4582 | new_result_block->used, |
4583 | header->length())); |
4584 | |
4585 | Query_cache_result *new_result = new_result_block->result(); |
4586 | new_result->parent(block); |
4587 | uchar *write_to = (uchar*) new_result->data(); |
4588 | Query_cache_block *result_block = first_result; |
4589 | do |
4590 | { |
4591 | size_t len = (result_block->used - result_block->headers_len() - |
4592 | ALIGN_SIZE(sizeof(Query_cache_result))); |
4593 | DBUG_PRINT("loop" , ("add block %zu/%zu (%zu)" , |
4594 | result_block->length, |
4595 | result_block->used, |
4596 | len)); |
4597 | memcpy((char *) write_to, |
4598 | (char*) result_block->result()->data(), |
4599 | len); |
4600 | write_to += len; |
4601 | Query_cache_block *old_result_block = result_block; |
4602 | result_block = result_block->next; |
4603 | free_memory_block(old_result_block); |
4604 | } while (result_block != first_result); |
4605 | BLOCK_UNLOCK_WR(block); |
4606 | } |
4607 | } |
4608 | block = block->next; |
4609 | } while ( block != queries_blocks ); |
4610 | } |
4611 | DBUG_RETURN(has_moving); |
4612 | } |
4613 | |
4614 | |
4615 | uint Query_cache::filename_2_table_key (char *key, const char *path, |
4616 | uint32 *db_length) |
4617 | { |
4618 | char tablename[FN_REFLEN+2], *filename, *dbname; |
4619 | DBUG_ENTER("Query_cache::filename_2_table_key" ); |
4620 | |
4621 | /* Safety if filename didn't have a directory name */ |
4622 | tablename[0]= FN_LIBCHAR; |
4623 | tablename[1]= FN_LIBCHAR; |
4624 | /* Convert filename to this OS's format in tablename */ |
4625 | fn_format(tablename + 2, path, "" , "" , MY_REPLACE_EXT); |
4626 | filename= tablename + dirname_length(tablename + 2) + 2; |
4627 | /* Find start of databasename */ |
4628 | for (dbname= filename - 2 ; dbname[-1] != FN_LIBCHAR ; dbname--) ; |
4629 | *db_length= (uint32)(filename - dbname) - 1; |
4630 | DBUG_PRINT("qcache" , ("table '%-.*s.%s'" , *db_length, dbname, filename)); |
4631 | |
4632 | DBUG_RETURN((uint) (strmake(strmake(key, dbname, |
4633 | MY_MIN(*db_length, NAME_LEN)) + 1, |
4634 | filename, NAME_LEN) - key) + 1); |
4635 | } |
4636 | |
4637 | /**************************************************************************** |
4638 | Functions to be used when debugging |
4639 | ****************************************************************************/ |
4640 | |
4641 | #if defined(DBUG_OFF) && !defined(USE_QUERY_CACHE_INTEGRITY_CHECK) |
4642 | |
4643 | void wreck(uint line, const char *message) { query_cache_size = 0; } |
4644 | void bins_dump() {} |
4645 | void cache_dump() {} |
4646 | void queries_dump() {} |
4647 | void tables_dump() {} |
4648 | my_bool check_integrity(bool not_locked) { return 0; } |
4649 | my_bool in_list(Query_cache_block * root, Query_cache_block * point, |
4650 | const char *name) { return 0;} |
4651 | my_bool in_blocks(Query_cache_block * point) { return 0; } |
4652 | |
4653 | #else |
4654 | |
4655 | |
4656 | /* |
4657 | Debug method which switch query cache off but left content for |
4658 | investigation. |
4659 | |
4660 | SYNOPSIS |
4661 | Query_cache::wreck() |
4662 | line line of the wreck() call |
4663 | message message for logging |
4664 | */ |
4665 | |
4666 | void Query_cache::wreck(uint line, const char *message) |
4667 | { |
4668 | THD *thd=current_thd; |
4669 | DBUG_ENTER("Query_cache::wreck" ); |
4670 | query_cache_size = 0; |
4671 | if (*message) |
4672 | DBUG_PRINT("error" , (" %s" , message)); |
4673 | DBUG_PRINT("warning" , ("==================================" )); |
4674 | DBUG_PRINT("warning" , ("%5d QUERY CACHE WRECK => DISABLED" ,line)); |
4675 | DBUG_PRINT("warning" , ("==================================" )); |
4676 | if (thd) |
4677 | thd->set_killed(KILL_CONNECTION); |
4678 | cache_dump(); |
4679 | /* check_integrity(0); */ /* Can't call it here because of locks */ |
4680 | bins_dump(); |
4681 | DBUG_VOID_RETURN; |
4682 | } |
4683 | |
4684 | |
4685 | void Query_cache::bins_dump() |
4686 | { |
4687 | uint i; |
4688 | |
4689 | if (!initialized || query_cache_size == 0) |
4690 | { |
4691 | DBUG_PRINT("qcache" , ("Query Cache not initialized" )); |
4692 | return; |
4693 | } |
4694 | |
4695 | DBUG_PRINT("qcache" , ("mem_bin_num=%zu, mem_bin_steps=%zu" , |
4696 | mem_bin_num, mem_bin_steps)); |
4697 | DBUG_PRINT("qcache" , ("-------------------------" )); |
4698 | DBUG_PRINT("qcache" , (" size idx step" )); |
4699 | DBUG_PRINT("qcache" , ("-------------------------" )); |
4700 | for (i=0; i < mem_bin_steps; i++) |
4701 | { |
4702 | DBUG_PRINT("qcache" , ("%10zu %3zd %10zu" , steps[i].size, steps[i].idx, |
4703 | steps[i].increment)); |
4704 | } |
4705 | DBUG_PRINT("qcache" , ("-------------------------" )); |
4706 | DBUG_PRINT("qcache" , (" size num" )); |
4707 | DBUG_PRINT("qcache" , ("-------------------------" )); |
4708 | for (i=0; i < mem_bin_num; i++) |
4709 | { |
4710 | DBUG_PRINT("qcache" , ("%10zu %3d %p" , bins[i].size, bins[i].number, |
4711 | &(bins[i]))); |
4712 | if (bins[i].free_blocks) |
4713 | { |
4714 | Query_cache_block *block = bins[i].free_blocks; |
4715 | do{ |
4716 | DBUG_PRINT("qcache" , ("\\-- %zu %p %p %p %p %p" , |
4717 | block->length,block, |
4718 | block->next,block->prev, |
4719 | block->pnext,block->pprev)); |
4720 | block = block->next; |
4721 | } while ( block != bins[i].free_blocks ); |
4722 | } |
4723 | } |
4724 | DBUG_PRINT("qcache" , ("-------------------------" )); |
4725 | } |
4726 | |
4727 | |
4728 | void Query_cache::cache_dump() |
4729 | { |
4730 | if (!initialized || query_cache_size == 0) |
4731 | { |
4732 | DBUG_PRINT("qcache" , ("Query Cache not initialized" )); |
4733 | return; |
4734 | } |
4735 | |
4736 | DBUG_PRINT("qcache" , ("-------------------------------------" )); |
4737 | DBUG_PRINT("qcache" , (" length used t nt" )); |
4738 | DBUG_PRINT("qcache" , ("-------------------------------------" )); |
4739 | Query_cache_block *i = first_block; |
4740 | do |
4741 | { |
4742 | DBUG_PRINT("qcache" , |
4743 | ("%10zu %10zu %1d %2d %p %p %p %p %p" , |
4744 | i->length, i->used, (int)i->type, |
4745 | i->n_tables,i, |
4746 | i->next,i->prev,i->pnext, |
4747 | i->pprev)); |
4748 | i = i->pnext; |
4749 | } while ( i != first_block ); |
4750 | DBUG_PRINT("qcache" , ("-------------------------------------" )); |
4751 | } |
4752 | |
4753 | |
4754 | void Query_cache::queries_dump() |
4755 | { |
4756 | |
4757 | if (!initialized) |
4758 | { |
4759 | DBUG_PRINT("qcache" , ("Query Cache not initialized" )); |
4760 | return; |
4761 | } |
4762 | |
4763 | DBUG_PRINT("qcache" , ("------------------" )); |
4764 | DBUG_PRINT("qcache" , (" QUERIES" )); |
4765 | DBUG_PRINT("qcache" , ("------------------" )); |
4766 | if (queries_blocks != 0) |
4767 | { |
4768 | Query_cache_block *block = queries_blocks; |
4769 | do |
4770 | { |
4771 | size_t len; |
4772 | char *str = (char*) query_cache_query_get_key((uchar*) block, &len, 0); |
4773 | len-= QUERY_CACHE_FLAGS_SIZE; // Point at flags |
4774 | Query_cache_query_flags flags; |
4775 | memcpy(&flags, str+len, QUERY_CACHE_FLAGS_SIZE); |
4776 | str[len]= 0; // make zero ending DB name |
4777 | DBUG_PRINT("qcache" , ("F: %u C: %u L: %llu T: '%s' (%zu) '%s' '%s'" , |
4778 | flags.client_long_flag, |
4779 | flags.character_set_client_num, |
4780 | flags.limit, |
4781 | flags.time_zone->get_name()->ptr(), |
4782 | len, str, strend(str)+1)); |
4783 | DBUG_PRINT("qcache" , ("-b- %p %p %p %p %p" , block, |
4784 | block->next, block->prev, |
4785 | block->pnext,block->pprev)); |
4786 | memcpy(str + len, &flags, QUERY_CACHE_FLAGS_SIZE); // restore flags |
4787 | for (TABLE_COUNTER_TYPE t= 0; t < block->n_tables; t++) |
4788 | { |
4789 | Query_cache_table *table= block->table(t)->parent; |
4790 | DBUG_PRINT("qcache" , ("-t- '%s' '%s'" , table->db(), table->table())); |
4791 | } |
4792 | Query_cache_query *header = block->query(); |
4793 | if (header->result()) |
4794 | { |
4795 | Query_cache_block *result_block = header->result(); |
4796 | Query_cache_block *result_beg = result_block; |
4797 | do |
4798 | { |
4799 | DBUG_PRINT("qcache" , ("-r- %u %zu/%zu %p %p %p %p %p" , |
4800 | (uint) result_block->type, |
4801 | result_block->length, result_block->used, |
4802 | result_block, |
4803 | result_block->next, |
4804 | result_block->prev, |
4805 | result_block->pnext, |
4806 | result_block->pprev)); |
4807 | result_block = result_block->next; |
4808 | } while ( result_block != result_beg ); |
4809 | } |
4810 | } while ((block=block->next) != queries_blocks); |
4811 | } |
4812 | else |
4813 | { |
4814 | DBUG_PRINT("qcache" , ("no queries in list" )); |
4815 | } |
4816 | DBUG_PRINT("qcache" , ("------------------" )); |
4817 | } |
4818 | |
4819 | |
4820 | void Query_cache::tables_dump() |
4821 | { |
4822 | if (!initialized || query_cache_size == 0) |
4823 | { |
4824 | DBUG_PRINT("qcache" , ("Query Cache not initialized" )); |
4825 | return; |
4826 | } |
4827 | |
4828 | DBUG_PRINT("qcache" , ("--------------------" )); |
4829 | DBUG_PRINT("qcache" , ("TABLES" )); |
4830 | DBUG_PRINT("qcache" , ("--------------------" )); |
4831 | if (tables_blocks != 0) |
4832 | { |
4833 | Query_cache_block *table_block = tables_blocks; |
4834 | do |
4835 | { |
4836 | Query_cache_table *table = table_block->table(); |
4837 | DBUG_PRINT("qcache" , ("'%s' '%s'" , table->db(), table->table())); |
4838 | table_block = table_block->next; |
4839 | } while (table_block != tables_blocks); |
4840 | } |
4841 | else |
4842 | DBUG_PRINT("qcache" , ("no tables in list" )); |
4843 | DBUG_PRINT("qcache" , ("--------------------" )); |
4844 | } |
4845 | |
4846 | |
4847 | /** |
4848 | Checks integrity of the various linked lists |
4849 | |
4850 | @return Error status code |
4851 | @retval FALSE Query cache is operational. |
4852 | @retval TRUE Query cache is broken. |
4853 | */ |
4854 | |
4855 | my_bool Query_cache::check_integrity(bool locked) |
4856 | { |
4857 | my_bool result = 0; |
4858 | uint i; |
4859 | DBUG_ENTER("check_integrity" ); |
4860 | |
4861 | if (!locked) |
4862 | lock_and_suspend(); |
4863 | |
4864 | if (my_hash_check(&queries)) |
4865 | { |
4866 | DBUG_PRINT("error" , ("queries hash is damaged" )); |
4867 | result = 1; |
4868 | } |
4869 | |
4870 | if (my_hash_check(&tables)) |
4871 | { |
4872 | DBUG_PRINT("error" , ("tables hash is damaged" )); |
4873 | result = 1; |
4874 | } |
4875 | |
4876 | DBUG_PRINT("qcache" , ("physical address check ..." )); |
4877 | size_t free=0, used=0; |
4878 | Query_cache_block * block = first_block; |
4879 | do |
4880 | { |
4881 | /* When checking at system start, there is no block. */ |
4882 | if (!block) |
4883 | break; |
4884 | |
4885 | DBUG_PRINT("qcache" , ("block %p, type %u..." , |
4886 | block, (uint) block->type)); |
4887 | // Check allignment |
4888 | if ((((size_t)block) % ALIGN_SIZE(1)) != |
4889 | (((size_t)first_block) % ALIGN_SIZE(1))) |
4890 | { |
4891 | DBUG_PRINT("error" , |
4892 | ("block %p do not aligned by %d" , block, |
4893 | (int) ALIGN_SIZE(1))); |
4894 | result = 1; |
4895 | } |
4896 | // Check memory allocation |
4897 | if (block->pnext == first_block) // Is it last block? |
4898 | { |
4899 | if (((uchar*)block) + block->length != |
4900 | ((uchar*)first_block) + query_cache_size) |
4901 | { |
4902 | DBUG_PRINT("error" , |
4903 | ("block %p, type %u, ended at %p, but cache ended at %p" , |
4904 | block, (uint) block->type, |
4905 | (((uchar*)block) + block->length), |
4906 | (((uchar*)first_block) + query_cache_size))); |
4907 | result = 1; |
4908 | } |
4909 | } |
4910 | else |
4911 | if (((uchar*)block) + block->length != ((uchar*)block->pnext)) |
4912 | { |
4913 | DBUG_PRINT("error" , |
4914 | ("block %p, type %u, ended at %p, but next block beginning at %p" , |
4915 | block, (uint) block->type, |
4916 | (((uchar*)block) + block->length), |
4917 | ((uchar*)block->pnext))); |
4918 | } |
4919 | if (block->type == Query_cache_block::FREE) |
4920 | free+= block->length; |
4921 | else |
4922 | used+= block->length; |
4923 | switch(block->type) { |
4924 | case Query_cache_block::FREE: |
4925 | { |
4926 | Query_cache_memory_bin *bin = *((Query_cache_memory_bin **) |
4927 | block->data()); |
4928 | //is it correct pointer? |
4929 | if (((uchar*)bin) < ((uchar*)bins) || |
4930 | ((uchar*)bin) >= ((uchar*)first_block)) |
4931 | { |
4932 | DBUG_PRINT("error" , |
4933 | ("free block %p have bin pointer %p beyaond of bins array bounds [%p,%p]" , |
4934 | block, |
4935 | bin, |
4936 | bins, |
4937 | first_block)); |
4938 | result = 1; |
4939 | } |
4940 | else |
4941 | { |
4942 | size_t idx = (((uchar*)bin) - ((uchar*)bins)) / |
4943 | sizeof(Query_cache_memory_bin); |
4944 | if (in_list(bins[idx].free_blocks, block, "free memory" )) |
4945 | result = 1; |
4946 | } |
4947 | break; |
4948 | } |
4949 | case Query_cache_block::TABLE: |
4950 | if (in_list(tables_blocks, block, "tables" )) |
4951 | result = 1; |
4952 | if (in_table_list(block->table(0), block->table(0), "table list root" )) |
4953 | result = 1; |
4954 | break; |
4955 | case Query_cache_block::QUERY: |
4956 | { |
4957 | if (in_list(queries_blocks, block, "query" )) |
4958 | result = 1; |
4959 | for (TABLE_COUNTER_TYPE j=0; j < block->n_tables; j++) |
4960 | { |
4961 | Query_cache_block_table *block_table = block->table(j); |
4962 | Query_cache_block_table *block_table_root = |
4963 | (Query_cache_block_table *) |
4964 | (((uchar*)block_table->parent) - |
4965 | ALIGN_SIZE(sizeof(Query_cache_block_table))); |
4966 | |
4967 | if (in_table_list(block_table, block_table_root, "table list" )) |
4968 | result = 1; |
4969 | } |
4970 | break; |
4971 | } |
4972 | case Query_cache_block::RES_INCOMPLETE: |
4973 | // This type of block can be not lincked yet (in multithread environment) |
4974 | break; |
4975 | case Query_cache_block::RES_BEG: |
4976 | case Query_cache_block::RES_CONT: |
4977 | case Query_cache_block::RESULT: |
4978 | { |
4979 | Query_cache_block * query_block = block->result()->parent(); |
4980 | if (((uchar*)query_block) < ((uchar*)first_block) || |
4981 | ((uchar*)query_block) >= (((uchar*)first_block) + query_cache_size)) |
4982 | { |
4983 | DBUG_PRINT("error" , |
4984 | ("result block %p have query block pointer %p beyaond of block pool bounds [%p,%p]" , |
4985 | block, |
4986 | query_block, |
4987 | first_block, |
4988 | (((uchar*)first_block) + query_cache_size))); |
4989 | result = 1; |
4990 | } |
4991 | else |
4992 | { |
4993 | BLOCK_LOCK_RD(query_block); |
4994 | if (in_list(queries_blocks, query_block, "query from results" )) |
4995 | result = 1; |
4996 | if (in_list(query_block->query()->result(), block, |
4997 | "results" )) |
4998 | result = 1; |
4999 | BLOCK_UNLOCK_RD(query_block); |
5000 | } |
5001 | break; |
5002 | } |
5003 | default: |
5004 | DBUG_PRINT("error" , ("block %p have incorrect type %u" , |
5005 | block, block->type)); |
5006 | result = 1; |
5007 | } |
5008 | |
5009 | block = block->pnext; |
5010 | } while (block != first_block); |
5011 | |
5012 | if (used + free != query_cache_size) |
5013 | { |
5014 | DBUG_PRINT("error" , |
5015 | ("used memory (%zu) + free memory (%zu) != query_cache_size (%zu)" , |
5016 | used, free, query_cache_size)); |
5017 | result = 1; |
5018 | } |
5019 | |
5020 | if (free != free_memory) |
5021 | { |
5022 | DBUG_PRINT("error" , |
5023 | ("free memory (%zu) != free_memory (%zu)" , |
5024 | free, free_memory)); |
5025 | result = 1; |
5026 | } |
5027 | |
5028 | DBUG_PRINT("qcache" , ("check queries ..." )); |
5029 | if ((block = queries_blocks)) |
5030 | { |
5031 | do |
5032 | { |
5033 | DBUG_PRINT("qcache" , ("block %p, type %u..." , |
5034 | block, (uint) block->type)); |
5035 | size_t length; |
5036 | uchar *key = query_cache_query_get_key((uchar*) block, &length, 0); |
5037 | uchar* val = my_hash_search(&queries, key, length); |
5038 | if (((uchar*)block) != val) |
5039 | { |
5040 | DBUG_PRINT("error" , ("block %p found in queries hash like %p" , |
5041 | block, val)); |
5042 | } |
5043 | if (in_blocks(block)) |
5044 | result = 1; |
5045 | Query_cache_block * results = block->query()->result(); |
5046 | if (results) |
5047 | { |
5048 | Query_cache_block * result_block = results; |
5049 | do |
5050 | { |
5051 | DBUG_PRINT("qcache" , ("block %p, type %u..." , |
5052 | block, (uint) block->type)); |
5053 | if (in_blocks(result_block)) |
5054 | result = 1; |
5055 | |
5056 | result_block = result_block->next; |
5057 | } while (result_block != results); |
5058 | } |
5059 | block = block->next; |
5060 | } while (block != queries_blocks); |
5061 | } |
5062 | |
5063 | DBUG_PRINT("qcache" , ("check tables ..." )); |
5064 | if ((block = tables_blocks)) |
5065 | { |
5066 | do |
5067 | { |
5068 | DBUG_PRINT("qcache" , ("block %p, type %u..." , |
5069 | block, (uint) block->type)); |
5070 | size_t length; |
5071 | uchar *key = query_cache_table_get_key((uchar*) block, &length, 0); |
5072 | uchar* val = my_hash_search(&tables, key, length); |
5073 | if (((uchar*)block) != val) |
5074 | { |
5075 | DBUG_PRINT("error" , ("block %p found in tables hash like %p" , |
5076 | block, val)); |
5077 | } |
5078 | |
5079 | if (in_blocks(block)) |
5080 | result = 1; |
5081 | block=block->next; |
5082 | } while (block != tables_blocks); |
5083 | } |
5084 | |
5085 | DBUG_PRINT("qcache" , ("check free blocks" )); |
5086 | for (i = 0; i < mem_bin_num; i++) |
5087 | { |
5088 | if ((block = bins[i].free_blocks)) |
5089 | { |
5090 | uint count = 0; |
5091 | do |
5092 | { |
5093 | DBUG_PRINT("qcache" , ("block %p, type %u..." , |
5094 | block, (uint) block->type)); |
5095 | if (in_blocks(block)) |
5096 | result = 1; |
5097 | |
5098 | count++; |
5099 | block=block->next; |
5100 | } while (block != bins[i].free_blocks); |
5101 | if (count != bins[i].number) |
5102 | { |
5103 | DBUG_PRINT("error" , ("bins[%d].number= %d, but bin have %d blocks" , |
5104 | i, bins[i].number, count)); |
5105 | result = 1; |
5106 | } |
5107 | } |
5108 | } |
5109 | DBUG_ASSERT(result == 0); |
5110 | if (!locked) |
5111 | unlock(); |
5112 | DBUG_RETURN(result); |
5113 | } |
5114 | |
5115 | |
5116 | my_bool Query_cache::in_blocks(Query_cache_block * point) |
5117 | { |
5118 | my_bool result = 0; |
5119 | Query_cache_block *block = point; |
5120 | //back |
5121 | do |
5122 | { |
5123 | if (block->pprev->pnext != block) |
5124 | { |
5125 | DBUG_PRINT("error" , |
5126 | ("block %p in physical list is incorrect linked, prev block %p refered as next to %p (check from %p)" , |
5127 | block, block->pprev, |
5128 | block->pprev->pnext, |
5129 | point)); |
5130 | //back trace |
5131 | for (; block != point; block = block->pnext) |
5132 | DBUG_PRINT("error" , ("back trace %p" , block)); |
5133 | result = 1; |
5134 | goto err1; |
5135 | } |
5136 | block = block->pprev; |
5137 | } while (block != first_block && block != point); |
5138 | if (block != first_block) |
5139 | { |
5140 | DBUG_PRINT("error" , |
5141 | ("block %p (%p<-->%p) not owned by pysical list" , |
5142 | block, block->pprev, block->pnext)); |
5143 | return 1; |
5144 | } |
5145 | |
5146 | err1: |
5147 | //forward |
5148 | block = point; |
5149 | do |
5150 | { |
5151 | if (block->pnext->pprev != block) |
5152 | { |
5153 | DBUG_PRINT("error" , |
5154 | ("block %p in physicel list is incorrect linked, next block %p refered as prev to %p (check from %p)" , |
5155 | block, block->pnext, |
5156 | block->pnext->pprev, |
5157 | point)); |
5158 | //back trace |
5159 | for (; block != point; block = block->pprev) |
5160 | DBUG_PRINT("error" , ("back trace %p" , block)); |
5161 | result = 1; |
5162 | goto err2; |
5163 | } |
5164 | block = block->pnext; |
5165 | } while (block != first_block); |
5166 | err2: |
5167 | return result; |
5168 | } |
5169 | |
5170 | |
5171 | my_bool Query_cache::in_list(Query_cache_block * root, |
5172 | Query_cache_block * point, |
5173 | const char *name) |
5174 | { |
5175 | my_bool result = 0; |
5176 | Query_cache_block *block = point; |
5177 | //back |
5178 | do |
5179 | { |
5180 | if (block->prev->next != block) |
5181 | { |
5182 | DBUG_PRINT("error" , |
5183 | ("block %p in list '%s' %p is incorrect linked, prev block %p refered as next to %p (check from %p)" , |
5184 | block, name, root, block->prev, |
5185 | block->prev->next, |
5186 | point)); |
5187 | //back trace |
5188 | for (; block != point; block = block->next) |
5189 | DBUG_PRINT("error" , ("back trace %p" , block)); |
5190 | result = 1; |
5191 | goto err1; |
5192 | } |
5193 | block = block->prev; |
5194 | } while (block != root && block != point); |
5195 | if (block != root) |
5196 | { |
5197 | DBUG_PRINT("error" , |
5198 | ("block %p (%p<-->%p) not owned by list '%s' %p" , |
5199 | block, |
5200 | block->prev, block->next, |
5201 | name, root)); |
5202 | return 1; |
5203 | } |
5204 | err1: |
5205 | // forward |
5206 | block = point; |
5207 | do |
5208 | { |
5209 | if (block->next->prev != block) |
5210 | { |
5211 | DBUG_PRINT("error" , |
5212 | ("block %p in list '%s' %p is incorrect linked, next block %p refered as prev to %p (check from %p)" , |
5213 | block, name, root, block->next, |
5214 | block->next->prev, |
5215 | point)); |
5216 | //back trace |
5217 | for (; block != point; block = block->prev) |
5218 | DBUG_PRINT("error" , ("back trace %p" , block)); |
5219 | result = 1; |
5220 | goto err2; |
5221 | } |
5222 | block = block->next; |
5223 | } while (block != root); |
5224 | err2: |
5225 | return result; |
5226 | } |
5227 | |
5228 | void dump_node(Query_cache_block_table * node, |
5229 | const char * call, const char * descr) |
5230 | { |
5231 | DBUG_PRINT("qcache" , ("%s: %s: node: %p" , call, descr, node)); |
5232 | DBUG_PRINT("qcache" , ("%s: %s: node block: %p" , |
5233 | call, descr, node->block())); |
5234 | DBUG_PRINT("qcache" , ("%s: %s: next: %p" , call, descr, |
5235 | node->next)); |
5236 | DBUG_PRINT("qcache" , ("%s: %s: prev: %p" , call, descr, |
5237 | node->prev)); |
5238 | } |
5239 | |
5240 | my_bool Query_cache::in_table_list(Query_cache_block_table * root, |
5241 | Query_cache_block_table * point, |
5242 | const char *name) |
5243 | { |
5244 | my_bool result = 0; |
5245 | Query_cache_block_table *table = point; |
5246 | dump_node(root, name, "parameter root" ); |
5247 | //back |
5248 | do |
5249 | { |
5250 | dump_node(table, name, "list element << " ); |
5251 | if (table->prev->next != table) |
5252 | { |
5253 | DBUG_PRINT("error" , |
5254 | ("table %p(%p) in list '%s' %p(%p) is incorrect linked, prev table %p(%p) refered as next to %p(%p) (check from %p(%p))" , |
5255 | table, table->block(), name, |
5256 | root, root->block(), |
5257 | table->prev, table->prev->block(), |
5258 | table->prev->next, |
5259 | table->prev->next->block(), |
5260 | point, point->block())); |
5261 | //back trace |
5262 | for (; table != point; table = table->next) |
5263 | DBUG_PRINT("error" , ("back trace %p(%p)" , |
5264 | table, table->block())); |
5265 | result = 1; |
5266 | goto err1; |
5267 | } |
5268 | table = table->prev; |
5269 | } while (table != root && table != point); |
5270 | if (table != root) |
5271 | { |
5272 | DBUG_PRINT("error" , |
5273 | ("table %p(%p) (%p(%p)<-->%p(%p)) not owned by list '%s' %p(%p)" , |
5274 | table, table->block(), |
5275 | table->prev, table->prev->block(), |
5276 | table->next, table->next->block(), |
5277 | name, root, root->block())); |
5278 | return 1; |
5279 | } |
5280 | err1: |
5281 | // forward |
5282 | table = point; |
5283 | do |
5284 | { |
5285 | dump_node(table, name, "list element >> " ); |
5286 | if (table->next->prev != table) |
5287 | { |
5288 | DBUG_PRINT("error" , |
5289 | ("table %p(%p) in list '%s' %p(%p) is incorrect linked, next table %p(%p) refered as prev to %p(%p) (check from %p(%p))" , |
5290 | table, table->block(), |
5291 | name, root, root->block(), |
5292 | table->next, table->next->block(), |
5293 | table->next->prev, |
5294 | table->next->prev->block(), |
5295 | point, point->block())); |
5296 | //back trace |
5297 | for (; table != point; table = table->prev) |
5298 | DBUG_PRINT("error" , ("back trace %p(%p)" , |
5299 | table, table->block())); |
5300 | result = 1; |
5301 | goto err2; |
5302 | } |
5303 | table = table->next; |
5304 | } while (table != root); |
5305 | err2: |
5306 | return result; |
5307 | } |
5308 | |
5309 | #endif /* DBUG_OFF */ |
5310 | |
5311 | #endif /*HAVE_QUERY_CACHE*/ |
5312 | |
5313 | |