1 | /*------------------------------------------------------------------------- |
2 | * |
3 | * xlogarchive.c |
4 | * Functions for archiving WAL files and restoring from the archive. |
5 | * |
6 | * |
7 | * Portions Copyright (c) 1996-2019, PostgreSQL Global Development Group |
8 | * Portions Copyright (c) 1994, Regents of the University of California |
9 | * |
10 | * src/backend/access/transam/xlogarchive.c |
11 | * |
12 | *------------------------------------------------------------------------- |
13 | */ |
14 | |
15 | #include "postgres.h" |
16 | |
17 | #include <sys/stat.h> |
18 | #include <sys/wait.h> |
19 | #include <signal.h> |
20 | #include <unistd.h> |
21 | |
22 | #include "access/xlog.h" |
23 | #include "access/xlog_internal.h" |
24 | #include "miscadmin.h" |
25 | #include "postmaster/startup.h" |
26 | #include "replication/walsender.h" |
27 | #include "storage/fd.h" |
28 | #include "storage/ipc.h" |
29 | #include "storage/lwlock.h" |
30 | #include "storage/pmsignal.h" |
31 | |
32 | /* |
33 | * Attempt to retrieve the specified file from off-line archival storage. |
34 | * If successful, fill "path" with its complete path (note that this will be |
35 | * a temp file name that doesn't follow the normal naming convention), and |
36 | * return true. |
37 | * |
38 | * If not successful, fill "path" with the name of the normal on-line file |
39 | * (which may or may not actually exist, but we'll try to use it), and return |
40 | * false. |
41 | * |
42 | * For fixed-size files, the caller may pass the expected size as an |
43 | * additional crosscheck on successful recovery. If the file size is not |
44 | * known, set expectedSize = 0. |
45 | * |
46 | * When 'cleanupEnabled' is false, refrain from deleting any old WAL segments |
47 | * in the archive. This is used when fetching the initial checkpoint record, |
48 | * when we are not yet sure how far back we need the WAL. |
49 | */ |
50 | bool |
51 | RestoreArchivedFile(char *path, const char *xlogfname, |
52 | const char *recovername, off_t expectedSize, |
53 | bool cleanupEnabled) |
54 | { |
55 | char xlogpath[MAXPGPATH]; |
56 | char xlogRestoreCmd[MAXPGPATH]; |
57 | char lastRestartPointFname[MAXPGPATH]; |
58 | char *dp; |
59 | char *endp; |
60 | const char *sp; |
61 | int rc; |
62 | struct stat stat_buf; |
63 | XLogSegNo restartSegNo; |
64 | XLogRecPtr restartRedoPtr; |
65 | TimeLineID restartTli; |
66 | |
67 | /* In standby mode, restore_command might not be supplied */ |
68 | if (recoveryRestoreCommand == NULL || strcmp(recoveryRestoreCommand, "" ) == 0) |
69 | goto not_available; |
70 | |
71 | /* |
72 | * When doing archive recovery, we always prefer an archived log file even |
73 | * if a file of the same name exists in XLOGDIR. The reason is that the |
74 | * file in XLOGDIR could be an old, un-filled or partly-filled version |
75 | * that was copied and restored as part of backing up $PGDATA. |
76 | * |
77 | * We could try to optimize this slightly by checking the local copy |
78 | * lastchange timestamp against the archived copy, but we have no API to |
79 | * do this, nor can we guarantee that the lastchange timestamp was |
80 | * preserved correctly when we copied to archive. Our aim is robustness, |
81 | * so we elect not to do this. |
82 | * |
83 | * If we cannot obtain the log file from the archive, however, we will try |
84 | * to use the XLOGDIR file if it exists. This is so that we can make use |
85 | * of log segments that weren't yet transferred to the archive. |
86 | * |
87 | * Notice that we don't actually overwrite any files when we copy back |
88 | * from archive because the restore_command may inadvertently restore |
89 | * inappropriate xlogs, or they may be corrupt, so we may wish to fallback |
90 | * to the segments remaining in current XLOGDIR later. The |
91 | * copy-from-archive filename is always the same, ensuring that we don't |
92 | * run out of disk space on long recoveries. |
93 | */ |
94 | snprintf(xlogpath, MAXPGPATH, XLOGDIR "/%s" , recovername); |
95 | |
96 | /* |
97 | * Make sure there is no existing file named recovername. |
98 | */ |
99 | if (stat(xlogpath, &stat_buf) != 0) |
100 | { |
101 | if (errno != ENOENT) |
102 | ereport(FATAL, |
103 | (errcode_for_file_access(), |
104 | errmsg("could not stat file \"%s\": %m" , |
105 | xlogpath))); |
106 | } |
107 | else |
108 | { |
109 | if (unlink(xlogpath) != 0) |
110 | ereport(FATAL, |
111 | (errcode_for_file_access(), |
112 | errmsg("could not remove file \"%s\": %m" , |
113 | xlogpath))); |
114 | } |
115 | |
116 | /* |
117 | * Calculate the archive file cutoff point for use during log shipping |
118 | * replication. All files earlier than this point can be deleted from the |
119 | * archive, though there is no requirement to do so. |
120 | * |
121 | * If cleanup is not enabled, initialise this with the filename of |
122 | * InvalidXLogRecPtr, which will prevent the deletion of any WAL files |
123 | * from the archive because of the alphabetic sorting property of WAL |
124 | * filenames. |
125 | * |
126 | * Once we have successfully located the redo pointer of the checkpoint |
127 | * from which we start recovery we never request a file prior to the redo |
128 | * pointer of the last restartpoint. When redo begins we know that we have |
129 | * successfully located it, so there is no need for additional status |
130 | * flags to signify the point when we can begin deleting WAL files from |
131 | * the archive. |
132 | */ |
133 | if (cleanupEnabled) |
134 | { |
135 | GetOldestRestartPoint(&restartRedoPtr, &restartTli); |
136 | XLByteToSeg(restartRedoPtr, restartSegNo, wal_segment_size); |
137 | XLogFileName(lastRestartPointFname, restartTli, restartSegNo, |
138 | wal_segment_size); |
139 | /* we shouldn't need anything earlier than last restart point */ |
140 | Assert(strcmp(lastRestartPointFname, xlogfname) <= 0); |
141 | } |
142 | else |
143 | XLogFileName(lastRestartPointFname, 0, 0L, wal_segment_size); |
144 | |
145 | /* |
146 | * construct the command to be executed |
147 | */ |
148 | dp = xlogRestoreCmd; |
149 | endp = xlogRestoreCmd + MAXPGPATH - 1; |
150 | *endp = '\0'; |
151 | |
152 | for (sp = recoveryRestoreCommand; *sp; sp++) |
153 | { |
154 | if (*sp == '%') |
155 | { |
156 | switch (sp[1]) |
157 | { |
158 | case 'p': |
159 | /* %p: relative path of target file */ |
160 | sp++; |
161 | StrNCpy(dp, xlogpath, endp - dp); |
162 | make_native_path(dp); |
163 | dp += strlen(dp); |
164 | break; |
165 | case 'f': |
166 | /* %f: filename of desired file */ |
167 | sp++; |
168 | StrNCpy(dp, xlogfname, endp - dp); |
169 | dp += strlen(dp); |
170 | break; |
171 | case 'r': |
172 | /* %r: filename of last restartpoint */ |
173 | sp++; |
174 | StrNCpy(dp, lastRestartPointFname, endp - dp); |
175 | dp += strlen(dp); |
176 | break; |
177 | case '%': |
178 | /* convert %% to a single % */ |
179 | sp++; |
180 | if (dp < endp) |
181 | *dp++ = *sp; |
182 | break; |
183 | default: |
184 | /* otherwise treat the % as not special */ |
185 | if (dp < endp) |
186 | *dp++ = *sp; |
187 | break; |
188 | } |
189 | } |
190 | else |
191 | { |
192 | if (dp < endp) |
193 | *dp++ = *sp; |
194 | } |
195 | } |
196 | *dp = '\0'; |
197 | |
198 | ereport(DEBUG3, |
199 | (errmsg_internal("executing restore command \"%s\"" , |
200 | xlogRestoreCmd))); |
201 | |
202 | /* |
203 | * Check signals before restore command and reset afterwards. |
204 | */ |
205 | PreRestoreCommand(); |
206 | |
207 | /* |
208 | * Copy xlog from archival storage to XLOGDIR |
209 | */ |
210 | rc = system(xlogRestoreCmd); |
211 | |
212 | PostRestoreCommand(); |
213 | |
214 | if (rc == 0) |
215 | { |
216 | /* |
217 | * command apparently succeeded, but let's make sure the file is |
218 | * really there now and has the correct size. |
219 | */ |
220 | if (stat(xlogpath, &stat_buf) == 0) |
221 | { |
222 | if (expectedSize > 0 && stat_buf.st_size != expectedSize) |
223 | { |
224 | int elevel; |
225 | |
226 | /* |
227 | * If we find a partial file in standby mode, we assume it's |
228 | * because it's just being copied to the archive, and keep |
229 | * trying. |
230 | * |
231 | * Otherwise treat a wrong-sized file as FATAL to ensure the |
232 | * DBA would notice it, but is that too strong? We could try |
233 | * to plow ahead with a local copy of the file ... but the |
234 | * problem is that there probably isn't one, and we'd |
235 | * incorrectly conclude we've reached the end of WAL and we're |
236 | * done recovering ... |
237 | */ |
238 | if (StandbyMode && stat_buf.st_size < expectedSize) |
239 | elevel = DEBUG1; |
240 | else |
241 | elevel = FATAL; |
242 | ereport(elevel, |
243 | (errmsg("archive file \"%s\" has wrong size: %lu instead of %lu" , |
244 | xlogfname, |
245 | (unsigned long) stat_buf.st_size, |
246 | (unsigned long) expectedSize))); |
247 | return false; |
248 | } |
249 | else |
250 | { |
251 | ereport(LOG, |
252 | (errmsg("restored log file \"%s\" from archive" , |
253 | xlogfname))); |
254 | strcpy(path, xlogpath); |
255 | return true; |
256 | } |
257 | } |
258 | else |
259 | { |
260 | /* stat failed */ |
261 | if (errno != ENOENT) |
262 | ereport(FATAL, |
263 | (errcode_for_file_access(), |
264 | errmsg("could not stat file \"%s\": %m" , |
265 | xlogpath))); |
266 | } |
267 | } |
268 | |
269 | /* |
270 | * Remember, we rollforward UNTIL the restore fails so failure here is |
271 | * just part of the process... that makes it difficult to determine |
272 | * whether the restore failed because there isn't an archive to restore, |
273 | * or because the administrator has specified the restore program |
274 | * incorrectly. We have to assume the former. |
275 | * |
276 | * However, if the failure was due to any sort of signal, it's best to |
277 | * punt and abort recovery. (If we "return false" here, upper levels will |
278 | * assume that recovery is complete and start up the database!) It's |
279 | * essential to abort on child SIGINT and SIGQUIT, because per spec |
280 | * system() ignores SIGINT and SIGQUIT while waiting; if we see one of |
281 | * those it's a good bet we should have gotten it too. |
282 | * |
283 | * On SIGTERM, assume we have received a fast shutdown request, and exit |
284 | * cleanly. It's pure chance whether we receive the SIGTERM first, or the |
285 | * child process. If we receive it first, the signal handler will call |
286 | * proc_exit, otherwise we do it here. If we or the child process received |
287 | * SIGTERM for any other reason than a fast shutdown request, postmaster |
288 | * will perform an immediate shutdown when it sees us exiting |
289 | * unexpectedly. |
290 | * |
291 | * We treat hard shell errors such as "command not found" as fatal, too. |
292 | */ |
293 | if (wait_result_is_signal(rc, SIGTERM)) |
294 | proc_exit(1); |
295 | |
296 | ereport(wait_result_is_any_signal(rc, true) ? FATAL : DEBUG2, |
297 | (errmsg("could not restore file \"%s\" from archive: %s" , |
298 | xlogfname, wait_result_to_str(rc)))); |
299 | |
300 | not_available: |
301 | |
302 | /* |
303 | * if an archived file is not available, there might still be a version of |
304 | * this file in XLOGDIR, so return that as the filename to open. |
305 | * |
306 | * In many recovery scenarios we expect this to fail also, but if so that |
307 | * just means we've reached the end of WAL. |
308 | */ |
309 | snprintf(path, MAXPGPATH, XLOGDIR "/%s" , xlogfname); |
310 | return false; |
311 | } |
312 | |
313 | /* |
314 | * Attempt to execute an external shell command during recovery. |
315 | * |
316 | * 'command' is the shell command to be executed, 'commandName' is a |
317 | * human-readable name describing the command emitted in the logs. If |
318 | * 'failOnSignal' is true and the command is killed by a signal, a FATAL |
319 | * error is thrown. Otherwise a WARNING is emitted. |
320 | * |
321 | * This is currently used for recovery_end_command and archive_cleanup_command. |
322 | */ |
323 | void |
324 | ExecuteRecoveryCommand(const char *command, const char *commandName, bool failOnSignal) |
325 | { |
326 | char xlogRecoveryCmd[MAXPGPATH]; |
327 | char lastRestartPointFname[MAXPGPATH]; |
328 | char *dp; |
329 | char *endp; |
330 | const char *sp; |
331 | int rc; |
332 | XLogSegNo restartSegNo; |
333 | XLogRecPtr restartRedoPtr; |
334 | TimeLineID restartTli; |
335 | |
336 | Assert(command && commandName); |
337 | |
338 | /* |
339 | * Calculate the archive file cutoff point for use during log shipping |
340 | * replication. All files earlier than this point can be deleted from the |
341 | * archive, though there is no requirement to do so. |
342 | */ |
343 | GetOldestRestartPoint(&restartRedoPtr, &restartTli); |
344 | XLByteToSeg(restartRedoPtr, restartSegNo, wal_segment_size); |
345 | XLogFileName(lastRestartPointFname, restartTli, restartSegNo, |
346 | wal_segment_size); |
347 | |
348 | /* |
349 | * construct the command to be executed |
350 | */ |
351 | dp = xlogRecoveryCmd; |
352 | endp = xlogRecoveryCmd + MAXPGPATH - 1; |
353 | *endp = '\0'; |
354 | |
355 | for (sp = command; *sp; sp++) |
356 | { |
357 | if (*sp == '%') |
358 | { |
359 | switch (sp[1]) |
360 | { |
361 | case 'r': |
362 | /* %r: filename of last restartpoint */ |
363 | sp++; |
364 | StrNCpy(dp, lastRestartPointFname, endp - dp); |
365 | dp += strlen(dp); |
366 | break; |
367 | case '%': |
368 | /* convert %% to a single % */ |
369 | sp++; |
370 | if (dp < endp) |
371 | *dp++ = *sp; |
372 | break; |
373 | default: |
374 | /* otherwise treat the % as not special */ |
375 | if (dp < endp) |
376 | *dp++ = *sp; |
377 | break; |
378 | } |
379 | } |
380 | else |
381 | { |
382 | if (dp < endp) |
383 | *dp++ = *sp; |
384 | } |
385 | } |
386 | *dp = '\0'; |
387 | |
388 | ereport(DEBUG3, |
389 | (errmsg_internal("executing %s \"%s\"" , commandName, command))); |
390 | |
391 | /* |
392 | * execute the constructed command |
393 | */ |
394 | rc = system(xlogRecoveryCmd); |
395 | if (rc != 0) |
396 | { |
397 | /* |
398 | * If the failure was due to any sort of signal, it's best to punt and |
399 | * abort recovery. See comments in RestoreArchivedFile(). |
400 | */ |
401 | ereport((failOnSignal && wait_result_is_any_signal(rc, true)) ? FATAL : WARNING, |
402 | /*------ |
403 | translator: First %s represents a postgresql.conf parameter name like |
404 | "recovery_end_command", the 2nd is the value of that parameter, the |
405 | third an already translated error message. */ |
406 | (errmsg("%s \"%s\": %s" , commandName, |
407 | command, wait_result_to_str(rc)))); |
408 | } |
409 | } |
410 | |
411 | |
412 | /* |
413 | * A file was restored from the archive under a temporary filename (path), |
414 | * and now we want to keep it. Rename it under the permanent filename in |
415 | * pg_wal (xlogfname), replacing any existing file with the same name. |
416 | */ |
417 | void |
418 | KeepFileRestoredFromArchive(const char *path, const char *xlogfname) |
419 | { |
420 | char xlogfpath[MAXPGPATH]; |
421 | bool reload = false; |
422 | struct stat statbuf; |
423 | |
424 | snprintf(xlogfpath, MAXPGPATH, XLOGDIR "/%s" , xlogfname); |
425 | |
426 | if (stat(xlogfpath, &statbuf) == 0) |
427 | { |
428 | char oldpath[MAXPGPATH]; |
429 | |
430 | #ifdef WIN32 |
431 | static unsigned int deletedcounter = 1; |
432 | |
433 | /* |
434 | * On Windows, if another process (e.g a walsender process) holds the |
435 | * file open in FILE_SHARE_DELETE mode, unlink will succeed, but the |
436 | * file will still show up in directory listing until the last handle |
437 | * is closed, and we cannot rename the new file in its place until |
438 | * that. To avoid that problem, rename the old file to a temporary |
439 | * name first. Use a counter to create a unique filename, because the |
440 | * same file might be restored from the archive multiple times, and a |
441 | * walsender could still be holding onto an old deleted version of it. |
442 | */ |
443 | snprintf(oldpath, MAXPGPATH, "%s.deleted%u" , |
444 | xlogfpath, deletedcounter++); |
445 | if (rename(xlogfpath, oldpath) != 0) |
446 | { |
447 | ereport(ERROR, |
448 | (errcode_for_file_access(), |
449 | errmsg("could not rename file \"%s\" to \"%s\": %m" , |
450 | xlogfpath, oldpath))); |
451 | } |
452 | #else |
453 | /* same-size buffers, so this never truncates */ |
454 | strlcpy(oldpath, xlogfpath, MAXPGPATH); |
455 | #endif |
456 | if (unlink(oldpath) != 0) |
457 | ereport(FATAL, |
458 | (errcode_for_file_access(), |
459 | errmsg("could not remove file \"%s\": %m" , |
460 | xlogfpath))); |
461 | reload = true; |
462 | } |
463 | |
464 | durable_rename(path, xlogfpath, ERROR); |
465 | |
466 | /* |
467 | * Create .done file forcibly to prevent the restored segment from being |
468 | * archived again later. |
469 | */ |
470 | if (XLogArchiveMode != ARCHIVE_MODE_ALWAYS) |
471 | XLogArchiveForceDone(xlogfname); |
472 | else |
473 | XLogArchiveNotify(xlogfname); |
474 | |
475 | /* |
476 | * If the existing file was replaced, since walsenders might have it open, |
477 | * request them to reload a currently-open segment. This is only required |
478 | * for WAL segments, walsenders don't hold other files open, but there's |
479 | * no harm in doing this too often, and we don't know what kind of a file |
480 | * we're dealing with here. |
481 | */ |
482 | if (reload) |
483 | WalSndRqstFileReload(); |
484 | |
485 | /* |
486 | * Signal walsender that new WAL has arrived. Again, this isn't necessary |
487 | * if we restored something other than a WAL segment, but it does no harm |
488 | * either. |
489 | */ |
490 | WalSndWakeup(); |
491 | } |
492 | |
493 | /* |
494 | * XLogArchiveNotify |
495 | * |
496 | * Create an archive notification file |
497 | * |
498 | * The name of the notification file is the message that will be picked up |
499 | * by the archiver, e.g. we write 0000000100000001000000C6.ready |
500 | * and the archiver then knows to archive XLOGDIR/0000000100000001000000C6, |
501 | * then when complete, rename it to 0000000100000001000000C6.done |
502 | */ |
503 | void |
504 | XLogArchiveNotify(const char *xlog) |
505 | { |
506 | char archiveStatusPath[MAXPGPATH]; |
507 | FILE *fd; |
508 | |
509 | /* insert an otherwise empty file called <XLOG>.ready */ |
510 | StatusFilePath(archiveStatusPath, xlog, ".ready" ); |
511 | fd = AllocateFile(archiveStatusPath, "w" ); |
512 | if (fd == NULL) |
513 | { |
514 | ereport(LOG, |
515 | (errcode_for_file_access(), |
516 | errmsg("could not create archive status file \"%s\": %m" , |
517 | archiveStatusPath))); |
518 | return; |
519 | } |
520 | if (FreeFile(fd)) |
521 | { |
522 | ereport(LOG, |
523 | (errcode_for_file_access(), |
524 | errmsg("could not write archive status file \"%s\": %m" , |
525 | archiveStatusPath))); |
526 | return; |
527 | } |
528 | |
529 | /* Notify archiver that it's got something to do */ |
530 | if (IsUnderPostmaster) |
531 | SendPostmasterSignal(PMSIGNAL_WAKEN_ARCHIVER); |
532 | } |
533 | |
534 | /* |
535 | * Convenience routine to notify using segment number representation of filename |
536 | */ |
537 | void |
538 | XLogArchiveNotifySeg(XLogSegNo segno) |
539 | { |
540 | char xlog[MAXFNAMELEN]; |
541 | |
542 | XLogFileName(xlog, ThisTimeLineID, segno, wal_segment_size); |
543 | XLogArchiveNotify(xlog); |
544 | } |
545 | |
546 | /* |
547 | * XLogArchiveForceDone |
548 | * |
549 | * Emit notification forcibly that an XLOG segment file has been successfully |
550 | * archived, by creating <XLOG>.done regardless of whether <XLOG>.ready |
551 | * exists or not. |
552 | */ |
553 | void |
554 | XLogArchiveForceDone(const char *xlog) |
555 | { |
556 | char archiveReady[MAXPGPATH]; |
557 | char archiveDone[MAXPGPATH]; |
558 | struct stat stat_buf; |
559 | FILE *fd; |
560 | |
561 | /* Exit if already known done */ |
562 | StatusFilePath(archiveDone, xlog, ".done" ); |
563 | if (stat(archiveDone, &stat_buf) == 0) |
564 | return; |
565 | |
566 | /* If .ready exists, rename it to .done */ |
567 | StatusFilePath(archiveReady, xlog, ".ready" ); |
568 | if (stat(archiveReady, &stat_buf) == 0) |
569 | { |
570 | (void) durable_rename(archiveReady, archiveDone, WARNING); |
571 | return; |
572 | } |
573 | |
574 | /* insert an otherwise empty file called <XLOG>.done */ |
575 | fd = AllocateFile(archiveDone, "w" ); |
576 | if (fd == NULL) |
577 | { |
578 | ereport(LOG, |
579 | (errcode_for_file_access(), |
580 | errmsg("could not create archive status file \"%s\": %m" , |
581 | archiveDone))); |
582 | return; |
583 | } |
584 | if (FreeFile(fd)) |
585 | { |
586 | ereport(LOG, |
587 | (errcode_for_file_access(), |
588 | errmsg("could not write archive status file \"%s\": %m" , |
589 | archiveDone))); |
590 | return; |
591 | } |
592 | } |
593 | |
594 | /* |
595 | * XLogArchiveCheckDone |
596 | * |
597 | * This is called when we are ready to delete or recycle an old XLOG segment |
598 | * file or backup history file. If it is okay to delete it then return true. |
599 | * If it is not time to delete it, make sure a .ready file exists, and return |
600 | * false. |
601 | * |
602 | * If <XLOG>.done exists, then return true; else if <XLOG>.ready exists, |
603 | * then return false; else create <XLOG>.ready and return false. |
604 | * |
605 | * The reason we do things this way is so that if the original attempt to |
606 | * create <XLOG>.ready fails, we'll retry during subsequent checkpoints. |
607 | */ |
608 | bool |
609 | XLogArchiveCheckDone(const char *xlog) |
610 | { |
611 | char archiveStatusPath[MAXPGPATH]; |
612 | struct stat stat_buf; |
613 | bool inRecovery = RecoveryInProgress(); |
614 | |
615 | /* |
616 | * The file is always deletable if archive_mode is "off". On standbys |
617 | * archiving is disabled if archive_mode is "on", and enabled with |
618 | * "always". On a primary, archiving is enabled if archive_mode is "on" |
619 | * or "always". |
620 | */ |
621 | if (!((XLogArchivingActive() && !inRecovery) || |
622 | (XLogArchivingAlways() && inRecovery))) |
623 | return true; |
624 | |
625 | /* First check for .done --- this means archiver is done with it */ |
626 | StatusFilePath(archiveStatusPath, xlog, ".done" ); |
627 | if (stat(archiveStatusPath, &stat_buf) == 0) |
628 | return true; |
629 | |
630 | /* check for .ready --- this means archiver is still busy with it */ |
631 | StatusFilePath(archiveStatusPath, xlog, ".ready" ); |
632 | if (stat(archiveStatusPath, &stat_buf) == 0) |
633 | return false; |
634 | |
635 | /* Race condition --- maybe archiver just finished, so recheck */ |
636 | StatusFilePath(archiveStatusPath, xlog, ".done" ); |
637 | if (stat(archiveStatusPath, &stat_buf) == 0) |
638 | return true; |
639 | |
640 | /* Retry creation of the .ready file */ |
641 | XLogArchiveNotify(xlog); |
642 | return false; |
643 | } |
644 | |
645 | /* |
646 | * XLogArchiveIsBusy |
647 | * |
648 | * Check to see if an XLOG segment file is still unarchived. |
649 | * This is almost but not quite the inverse of XLogArchiveCheckDone: in |
650 | * the first place we aren't chartered to recreate the .ready file, and |
651 | * in the second place we should consider that if the file is already gone |
652 | * then it's not busy. (This check is needed to handle the race condition |
653 | * that a checkpoint already deleted the no-longer-needed file.) |
654 | */ |
655 | bool |
656 | XLogArchiveIsBusy(const char *xlog) |
657 | { |
658 | char archiveStatusPath[MAXPGPATH]; |
659 | struct stat stat_buf; |
660 | |
661 | /* First check for .done --- this means archiver is done with it */ |
662 | StatusFilePath(archiveStatusPath, xlog, ".done" ); |
663 | if (stat(archiveStatusPath, &stat_buf) == 0) |
664 | return false; |
665 | |
666 | /* check for .ready --- this means archiver is still busy with it */ |
667 | StatusFilePath(archiveStatusPath, xlog, ".ready" ); |
668 | if (stat(archiveStatusPath, &stat_buf) == 0) |
669 | return true; |
670 | |
671 | /* Race condition --- maybe archiver just finished, so recheck */ |
672 | StatusFilePath(archiveStatusPath, xlog, ".done" ); |
673 | if (stat(archiveStatusPath, &stat_buf) == 0) |
674 | return false; |
675 | |
676 | /* |
677 | * Check to see if the WAL file has been removed by checkpoint, which |
678 | * implies it has already been archived, and explains why we can't see a |
679 | * status file for it. |
680 | */ |
681 | snprintf(archiveStatusPath, MAXPGPATH, XLOGDIR "/%s" , xlog); |
682 | if (stat(archiveStatusPath, &stat_buf) != 0 && |
683 | errno == ENOENT) |
684 | return false; |
685 | |
686 | return true; |
687 | } |
688 | |
689 | /* |
690 | * XLogArchiveIsReadyOrDone |
691 | * |
692 | * Check to see if an XLOG segment file has a .ready or .done file. |
693 | * This is similar to XLogArchiveIsBusy(), but returns true if the file |
694 | * is already archived or is about to be archived. |
695 | * |
696 | * This is currently only used at recovery. During normal operation this |
697 | * would be racy: the file might get removed or marked with .ready as we're |
698 | * checking it, or immediately after we return. |
699 | */ |
700 | bool |
701 | XLogArchiveIsReadyOrDone(const char *xlog) |
702 | { |
703 | char archiveStatusPath[MAXPGPATH]; |
704 | struct stat stat_buf; |
705 | |
706 | /* First check for .done --- this means archiver is done with it */ |
707 | StatusFilePath(archiveStatusPath, xlog, ".done" ); |
708 | if (stat(archiveStatusPath, &stat_buf) == 0) |
709 | return true; |
710 | |
711 | /* check for .ready --- this means archiver is still busy with it */ |
712 | StatusFilePath(archiveStatusPath, xlog, ".ready" ); |
713 | if (stat(archiveStatusPath, &stat_buf) == 0) |
714 | return true; |
715 | |
716 | /* Race condition --- maybe archiver just finished, so recheck */ |
717 | StatusFilePath(archiveStatusPath, xlog, ".done" ); |
718 | if (stat(archiveStatusPath, &stat_buf) == 0) |
719 | return true; |
720 | |
721 | return false; |
722 | } |
723 | |
724 | /* |
725 | * XLogArchiveIsReady |
726 | * |
727 | * Check to see if an XLOG segment file has an archive notification (.ready) |
728 | * file. |
729 | */ |
730 | bool |
731 | XLogArchiveIsReady(const char *xlog) |
732 | { |
733 | char archiveStatusPath[MAXPGPATH]; |
734 | struct stat stat_buf; |
735 | |
736 | StatusFilePath(archiveStatusPath, xlog, ".ready" ); |
737 | if (stat(archiveStatusPath, &stat_buf) == 0) |
738 | return true; |
739 | |
740 | return false; |
741 | } |
742 | |
743 | /* |
744 | * XLogArchiveCleanup |
745 | * |
746 | * Cleanup archive notification file(s) for a particular xlog segment |
747 | */ |
748 | void |
749 | XLogArchiveCleanup(const char *xlog) |
750 | { |
751 | char archiveStatusPath[MAXPGPATH]; |
752 | |
753 | /* Remove the .done file */ |
754 | StatusFilePath(archiveStatusPath, xlog, ".done" ); |
755 | unlink(archiveStatusPath); |
756 | /* should we complain about failure? */ |
757 | |
758 | /* Remove the .ready file if present --- normally it shouldn't be */ |
759 | StatusFilePath(archiveStatusPath, xlog, ".ready" ); |
760 | unlink(archiveStatusPath); |
761 | /* should we complain about failure? */ |
762 | } |
763 | |