| 1 | /* |
| 2 | Copyright (c) 2000, 2011, Oracle and/or its affiliates |
| 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 |
| 15 | Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA */ |
| 16 | |
| 17 | /* open a MyISAM MERGE table */ |
| 18 | |
| 19 | #include "myrg_def.h" |
| 20 | #include <stddef.h> |
| 21 | #include <errno.h> |
| 22 | |
| 23 | /* |
| 24 | open a MyISAM MERGE table |
| 25 | if handle_locking is 0 then exit with error if some table is locked |
| 26 | if handle_locking is 1 then wait if table is locked |
| 27 | |
| 28 | NOTE: This function is only used in the MySQL server when a |
| 29 | table is cloned. It is also used for usage of MERGE |
| 30 | independent from MySQL. Currently there is some code |
| 31 | duplication between myrg_open() and myrg_parent_open() + |
| 32 | myrg_attach_children(). Please duplicate changes in these |
| 33 | functions or make common sub-functions. |
| 34 | */ |
| 35 | |
| 36 | MYRG_INFO *myrg_open(const char *name, int mode, int handle_locking) |
| 37 | { |
| 38 | int save_errno,errpos=0; |
| 39 | uint files= 0, i, UNINIT_VAR(key_parts), min_keys= 0; |
| 40 | size_t length, dir_length; |
| 41 | ulonglong file_offset=0; |
| 42 | char name_buff[FN_REFLEN*2],buff[FN_REFLEN],*end; |
| 43 | MYRG_INFO *m_info=0; |
| 44 | File fd; |
| 45 | IO_CACHE file; |
| 46 | MI_INFO *isam=0; |
| 47 | uint found_merge_insert_method= 0; |
| 48 | size_t name_buff_length; |
| 49 | my_bool bad_children= FALSE; |
| 50 | DBUG_ENTER("myrg_open" ); |
| 51 | |
| 52 | bzero((char*) &file,sizeof(file)); |
| 53 | if ((fd= mysql_file_open(rg_key_file_MRG, |
| 54 | fn_format(name_buff, name, "" , MYRG_NAME_EXT, |
| 55 | MY_UNPACK_FILENAME|MY_APPEND_EXT), |
| 56 | O_RDONLY | O_SHARE, MYF(0))) < 0) |
| 57 | goto err; |
| 58 | errpos=1; |
| 59 | if (init_io_cache(&file, fd, 4*IO_SIZE, READ_CACHE, 0, 0, |
| 60 | MYF(MY_WME | MY_NABP))) |
| 61 | goto err; |
| 62 | errpos=2; |
| 63 | dir_length=dirname_part(name_buff, name, &name_buff_length); |
| 64 | while ((length=my_b_gets(&file,buff,FN_REFLEN-1))) |
| 65 | { |
| 66 | if ((end=buff+length)[-1] == '\n') |
| 67 | end[-1]='\0'; |
| 68 | if (buff[0] && buff[0] != '#') |
| 69 | files++; |
| 70 | } |
| 71 | |
| 72 | my_b_seek(&file, 0); |
| 73 | while ((length=my_b_gets(&file,buff,FN_REFLEN-1))) |
| 74 | { |
| 75 | if ((end=buff+length)[-1] == '\n') |
| 76 | *--end='\0'; |
| 77 | if (!buff[0]) |
| 78 | continue; /* Skip empty lines */ |
| 79 | if (buff[0] == '#') |
| 80 | { |
| 81 | if (!strncmp(buff+1,"INSERT_METHOD=" ,14)) |
| 82 | { /* Lookup insert method */ |
| 83 | int tmp= find_type(buff + 15, &merge_insert_method, FIND_TYPE_BASIC); |
| 84 | found_merge_insert_method = (uint) (tmp >= 0 ? tmp : 0); |
| 85 | } |
| 86 | continue; /* Skip comments */ |
| 87 | } |
| 88 | |
| 89 | if (!has_path(buff)) |
| 90 | { |
| 91 | (void) strmake(name_buff+dir_length,buff, |
| 92 | sizeof(name_buff)-1-dir_length); |
| 93 | (void) cleanup_dirname(buff,name_buff); |
| 94 | } |
| 95 | else |
| 96 | fn_format(buff, buff, "" , "" , 0); |
| 97 | if (!(isam=mi_open(buff,mode,(handle_locking?HA_OPEN_WAIT_IF_LOCKED:0) | |
| 98 | HA_OPEN_MERGE_TABLE))) |
| 99 | { |
| 100 | if (handle_locking & HA_OPEN_FOR_REPAIR) |
| 101 | { |
| 102 | myrg_print_wrong_table(buff); |
| 103 | bad_children= TRUE; |
| 104 | continue; |
| 105 | } |
| 106 | goto bad_children; |
| 107 | } |
| 108 | if (!m_info) /* First file */ |
| 109 | { |
| 110 | key_parts=isam->s->base.key_parts; |
| 111 | if (!(m_info= (MYRG_INFO*) my_malloc(sizeof(MYRG_INFO) + |
| 112 | files*sizeof(MYRG_TABLE) + |
| 113 | key_parts*sizeof(long), |
| 114 | MYF(MY_WME|MY_ZEROFILL)))) |
| 115 | goto err; |
| 116 | DBUG_ASSERT(files); |
| 117 | m_info->open_tables=(MYRG_TABLE *) (m_info+1); |
| 118 | m_info->rec_per_key_part=(ulong *) (m_info->open_tables+files); |
| 119 | m_info->tables= files; |
| 120 | files= 0; |
| 121 | m_info->reclength=isam->s->base.reclength; |
| 122 | min_keys= isam->s->base.keys; |
| 123 | errpos=3; |
| 124 | } |
| 125 | m_info->open_tables[files].table= isam; |
| 126 | m_info->open_tables[files].file_offset=(my_off_t) file_offset; |
| 127 | file_offset+=isam->state->data_file_length; |
| 128 | files++; |
| 129 | if (m_info->reclength != isam->s->base.reclength) |
| 130 | { |
| 131 | if (handle_locking & HA_OPEN_FOR_REPAIR) |
| 132 | { |
| 133 | myrg_print_wrong_table(buff); |
| 134 | bad_children= TRUE; |
| 135 | continue; |
| 136 | } |
| 137 | goto bad_children; |
| 138 | } |
| 139 | m_info->options|= isam->s->options; |
| 140 | m_info->records+= isam->state->records; |
| 141 | m_info->del+= isam->state->del; |
| 142 | m_info->data_file_length+= isam->state->data_file_length; |
| 143 | if (min_keys > isam->s->base.keys) |
| 144 | min_keys= isam->s->base.keys; |
| 145 | for (i=0; i < key_parts; i++) |
| 146 | m_info->rec_per_key_part[i]+= (isam->s->state.rec_per_key_part[i] / |
| 147 | m_info->tables); |
| 148 | } |
| 149 | |
| 150 | if (bad_children) |
| 151 | goto bad_children; |
| 152 | if (!m_info && !(m_info= (MYRG_INFO*) my_malloc(sizeof(MYRG_INFO), |
| 153 | MYF(MY_WME | MY_ZEROFILL)))) |
| 154 | goto err; |
| 155 | /* Don't mark table readonly, for ALTER TABLE ... UNION=(...) to work */ |
| 156 | m_info->options&= ~(HA_OPTION_COMPRESS_RECORD | HA_OPTION_READ_ONLY_DATA); |
| 157 | m_info->merge_insert_method= found_merge_insert_method; |
| 158 | |
| 159 | if (sizeof(my_off_t) == 4 && file_offset > (ulonglong) (ulong) ~0L) |
| 160 | { |
| 161 | my_errno=HA_ERR_RECORD_FILE_FULL; |
| 162 | goto err; |
| 163 | } |
| 164 | m_info->keys= min_keys; |
| 165 | bzero((char*) &m_info->by_key,sizeof(m_info->by_key)); |
| 166 | |
| 167 | /* this works ok if the table list is empty */ |
| 168 | m_info->end_table=m_info->open_tables+files; |
| 169 | m_info->last_used_table=m_info->open_tables; |
| 170 | m_info->children_attached= TRUE; |
| 171 | |
| 172 | (void) mysql_file_close(fd, MYF(0)); |
| 173 | end_io_cache(&file); |
| 174 | mysql_mutex_init(rg_key_mutex_MYRG_INFO_mutex, |
| 175 | &m_info->mutex, MY_MUTEX_INIT_FAST); |
| 176 | m_info->open_list.data=(void*) m_info; |
| 177 | mysql_mutex_lock(&THR_LOCK_open); |
| 178 | myrg_open_list=list_add(myrg_open_list,&m_info->open_list); |
| 179 | mysql_mutex_unlock(&THR_LOCK_open); |
| 180 | DBUG_RETURN(m_info); |
| 181 | |
| 182 | bad_children: |
| 183 | my_errno= HA_ERR_WRONG_MRG_TABLE_DEF; |
| 184 | err: |
| 185 | save_errno=my_errno; |
| 186 | switch (errpos) { |
| 187 | case 3: |
| 188 | while (files) |
| 189 | (void) mi_close(m_info->open_tables[--files].table); |
| 190 | my_free(m_info); |
| 191 | /* Fall through */ |
| 192 | case 2: |
| 193 | end_io_cache(&file); |
| 194 | /* Fall through */ |
| 195 | case 1: |
| 196 | (void) mysql_file_close(fd, MYF(0)); |
| 197 | } |
| 198 | my_errno=save_errno; |
| 199 | DBUG_RETURN (NULL); |
| 200 | } |
| 201 | |
| 202 | |
| 203 | /** |
| 204 | @brief Open parent table of a MyISAM MERGE table. |
| 205 | |
| 206 | @detail Open MERGE meta file to get the table name paths for the child |
| 207 | tables. Count the children. Allocate and initialize MYRG_INFO |
| 208 | structure. Call a callback function for each child table. |
| 209 | |
| 210 | @param[in] parent_name merge table name path as "database/table" |
| 211 | @param[in] callback function to call for each child table |
| 212 | @param[in] callback_param data pointer to give to the callback |
| 213 | |
| 214 | @return MYRG_INFO pointer |
| 215 | @retval != NULL OK |
| 216 | @retval NULL Error |
| 217 | |
| 218 | @note: Currently there is some code duplication between myrg_open() |
| 219 | and myrg_parent_open() + myrg_attach_children(). Please duplicate |
| 220 | changes in these functions or make common sub-functions. |
| 221 | */ |
| 222 | |
| 223 | MYRG_INFO *myrg_parent_open(const char *parent_name, |
| 224 | int (*callback)(void*, const char*), |
| 225 | void *callback_param) |
| 226 | { |
| 227 | MYRG_INFO *UNINIT_VAR(m_info); |
| 228 | int rc; |
| 229 | int errpos; |
| 230 | int save_errno; |
| 231 | int insert_method; |
| 232 | size_t length; |
| 233 | uint child_count; |
| 234 | File fd; |
| 235 | IO_CACHE file_cache; |
| 236 | char parent_name_buff[FN_REFLEN * 2]; |
| 237 | char child_name_buff[FN_REFLEN]; |
| 238 | DBUG_ENTER("myrg_parent_open" ); |
| 239 | |
| 240 | rc= 1; |
| 241 | errpos= 0; |
| 242 | bzero((char*) &file_cache, sizeof(file_cache)); |
| 243 | |
| 244 | /* Open MERGE meta file. */ |
| 245 | if ((fd= mysql_file_open(rg_key_file_MRG, |
| 246 | fn_format(parent_name_buff, parent_name, |
| 247 | "" , MYRG_NAME_EXT, |
| 248 | MY_UNPACK_FILENAME|MY_APPEND_EXT), |
| 249 | O_RDONLY | O_SHARE, MYF(0))) < 0) |
| 250 | goto err; /* purecov: inspected */ |
| 251 | errpos= 1; |
| 252 | |
| 253 | if (init_io_cache(&file_cache, fd, 4 * IO_SIZE, READ_CACHE, 0, 0, |
| 254 | MYF(MY_WME | MY_NABP))) |
| 255 | goto err; /* purecov: inspected */ |
| 256 | errpos= 2; |
| 257 | |
| 258 | /* Count children. Determine insert method. */ |
| 259 | child_count= 0; |
| 260 | insert_method= 0; |
| 261 | while ((length= my_b_gets(&file_cache, child_name_buff, FN_REFLEN - 1))) |
| 262 | { |
| 263 | /* Remove line terminator. */ |
| 264 | if (child_name_buff[length - 1] == '\n') |
| 265 | child_name_buff[--length]= '\0'; |
| 266 | |
| 267 | /* Skip empty lines. */ |
| 268 | if (!child_name_buff[0]) |
| 269 | continue; /* purecov: inspected */ |
| 270 | |
| 271 | /* Skip comments, but evaluate insert method. */ |
| 272 | if (child_name_buff[0] == '#') |
| 273 | { |
| 274 | if (!strncmp(child_name_buff + 1, "INSERT_METHOD=" , 14)) |
| 275 | { |
| 276 | /* Compare buffer with global methods list: merge_insert_method. */ |
| 277 | insert_method= find_type(child_name_buff + 15, |
| 278 | &merge_insert_method, FIND_TYPE_BASIC); |
| 279 | } |
| 280 | continue; |
| 281 | } |
| 282 | |
| 283 | /* Count the child. */ |
| 284 | child_count++; |
| 285 | } |
| 286 | |
| 287 | /* Allocate MERGE parent table structure. */ |
| 288 | if (!(m_info= (MYRG_INFO*) my_malloc(sizeof(MYRG_INFO) + |
| 289 | child_count * sizeof(MYRG_TABLE), |
| 290 | MYF(MY_WME | MY_ZEROFILL)))) |
| 291 | goto err; /* purecov: inspected */ |
| 292 | errpos= 3; |
| 293 | m_info->open_tables= (MYRG_TABLE*) (m_info + 1); |
| 294 | m_info->tables= child_count; |
| 295 | m_info->merge_insert_method= insert_method > 0 ? insert_method : 0; |
| 296 | /* This works even if the table list is empty. */ |
| 297 | m_info->end_table= m_info->open_tables + child_count; |
| 298 | if (!child_count) |
| 299 | { |
| 300 | /* Do not attach/detach an empty child list. */ |
| 301 | m_info->children_attached= TRUE; |
| 302 | } |
| 303 | |
| 304 | /* Call callback for each child. */ |
| 305 | my_b_seek(&file_cache, 0); |
| 306 | while ((length= my_b_gets(&file_cache, child_name_buff, FN_REFLEN - 1))) |
| 307 | { |
| 308 | /* Remove line terminator. */ |
| 309 | if (child_name_buff[length - 1] == '\n') |
| 310 | child_name_buff[--length]= '\0'; |
| 311 | |
| 312 | /* Skip empty lines and comments. */ |
| 313 | if (!child_name_buff[0] || (child_name_buff[0] == '#')) |
| 314 | continue; |
| 315 | |
| 316 | DBUG_PRINT("info" , ("child: '%s'" , child_name_buff)); |
| 317 | |
| 318 | /* Callback registers child with handler table. */ |
| 319 | if ((rc= (*callback)(callback_param, child_name_buff))) |
| 320 | goto err; /* purecov: inspected */ |
| 321 | } |
| 322 | |
| 323 | end_io_cache(&file_cache); |
| 324 | (void) mysql_file_close(fd, MYF(0)); |
| 325 | mysql_mutex_init(rg_key_mutex_MYRG_INFO_mutex, |
| 326 | &m_info->mutex, MY_MUTEX_INIT_FAST); |
| 327 | |
| 328 | m_info->open_list.data= (void*) m_info; |
| 329 | mysql_mutex_lock(&THR_LOCK_open); |
| 330 | myrg_open_list= list_add(myrg_open_list, &m_info->open_list); |
| 331 | mysql_mutex_unlock(&THR_LOCK_open); |
| 332 | |
| 333 | DBUG_RETURN(m_info); |
| 334 | |
| 335 | /* purecov: begin inspected */ |
| 336 | err: |
| 337 | save_errno= my_errno; |
| 338 | switch (errpos) { |
| 339 | case 3: |
| 340 | my_free(m_info); |
| 341 | /* Fall through */ |
| 342 | case 2: |
| 343 | end_io_cache(&file_cache); |
| 344 | /* Fall through */ |
| 345 | case 1: |
| 346 | (void) mysql_file_close(fd, MYF(0)); |
| 347 | } |
| 348 | my_errno= save_errno; |
| 349 | DBUG_RETURN (NULL); |
| 350 | /* purecov: end */ |
| 351 | } |
| 352 | |
| 353 | |
| 354 | /** |
| 355 | @brief Attach children to a MyISAM MERGE parent table. |
| 356 | |
| 357 | @detail Call a callback function for each child table. |
| 358 | The callback returns the MyISAM table handle of the child table. |
| 359 | Check table definition match. |
| 360 | |
| 361 | @param[in] m_info MERGE parent table structure |
| 362 | @param[in] handle_locking if contains HA_OPEN_FOR_REPAIR, warn about |
| 363 | incompatible child tables, but continue |
| 364 | @param[in] callback function to call for each child table |
| 365 | @param[in] callback_param data pointer to give to the callback |
| 366 | @param[in] need_compat_check pointer to ha_myisammrg::need_compat_check |
| 367 | (we need this one to decide if previously |
| 368 | allocated buffers can be reused). |
| 369 | |
| 370 | @return status |
| 371 | @retval 0 OK |
| 372 | @retval != 0 Error |
| 373 | |
| 374 | @note: Currently there is some code duplication between myrg_open() |
| 375 | and myrg_parent_open() + myrg_attach_children(). Please duplicate |
| 376 | changes in these functions or make common sub-functions. |
| 377 | */ |
| 378 | |
| 379 | int myrg_attach_children(MYRG_INFO *m_info, int handle_locking, |
| 380 | MI_INFO *(*callback)(void*), |
| 381 | void *callback_param, my_bool *need_compat_check) |
| 382 | { |
| 383 | ulonglong file_offset; |
| 384 | MI_INFO *myisam; |
| 385 | int errpos; |
| 386 | int save_errno; |
| 387 | uint idx; |
| 388 | uint child_nr; |
| 389 | uint UNINIT_VAR(key_parts); |
| 390 | uint min_keys; |
| 391 | my_bool bad_children= FALSE; |
| 392 | my_bool first_child= TRUE; |
| 393 | DBUG_ENTER("myrg_attach_children" ); |
| 394 | DBUG_PRINT("myrg" , ("handle_locking: %d" , handle_locking)); |
| 395 | |
| 396 | /* |
| 397 | This function can be called while another thread is trying to abort |
| 398 | locks of this MERGE table. If the processor reorders instructions or |
| 399 | write to memory, 'children_attached' could be set before |
| 400 | 'open_tables' has all the pointers to the children. Use of a mutex |
| 401 | here and in ha_myisammrg::store_lock() forces consistent data. |
| 402 | */ |
| 403 | mysql_mutex_lock(&m_info->mutex); |
| 404 | errpos= 0; |
| 405 | file_offset= 0; |
| 406 | min_keys= 0; |
| 407 | for (child_nr= 0; child_nr < m_info->tables; child_nr++) |
| 408 | { |
| 409 | if (! (myisam= (*callback)(callback_param))) |
| 410 | { |
| 411 | if (handle_locking & HA_OPEN_FOR_REPAIR) |
| 412 | { |
| 413 | /* An appropriate error should've been already pushed by callback. */ |
| 414 | bad_children= TRUE; |
| 415 | continue; |
| 416 | } |
| 417 | goto bad_children; |
| 418 | } |
| 419 | |
| 420 | DBUG_PRINT("myrg" , ("child_nr: %u table: '%s'" , |
| 421 | child_nr, myisam->filename)); |
| 422 | |
| 423 | /* Special handling when the first child is attached. */ |
| 424 | if (first_child) |
| 425 | { |
| 426 | first_child= FALSE; |
| 427 | m_info->reclength= myisam->s->base.reclength; |
| 428 | min_keys= myisam->s->base.keys; |
| 429 | key_parts= myisam->s->base.key_parts; |
| 430 | if (*need_compat_check && m_info->rec_per_key_part) |
| 431 | { |
| 432 | my_free(m_info->rec_per_key_part); |
| 433 | m_info->rec_per_key_part= NULL; |
| 434 | } |
| 435 | if (!m_info->rec_per_key_part) |
| 436 | { |
| 437 | if(!(m_info->rec_per_key_part= (ulong*) |
| 438 | my_malloc(key_parts * sizeof(long), MYF(MY_WME)))) |
| 439 | goto err; /* purecov: inspected */ |
| 440 | errpos= 1; |
| 441 | } |
| 442 | bzero((char*) m_info->rec_per_key_part, key_parts * sizeof(long)); |
| 443 | } |
| 444 | |
| 445 | /* Add MyISAM table info. */ |
| 446 | m_info->open_tables[child_nr].table= myisam; |
| 447 | m_info->open_tables[child_nr].file_offset= (my_off_t) file_offset; |
| 448 | file_offset+= myisam->state->data_file_length; |
| 449 | /* Mark as MERGE table */ |
| 450 | myisam->open_flag|= HA_OPEN_MERGE_TABLE; |
| 451 | |
| 452 | /* Check table definition match. */ |
| 453 | if (m_info->reclength != myisam->s->base.reclength) |
| 454 | { |
| 455 | DBUG_PRINT("error" , ("definition mismatch table: '%s' repair: %d" , |
| 456 | myisam->filename, |
| 457 | (handle_locking & HA_OPEN_FOR_REPAIR))); |
| 458 | if (handle_locking & HA_OPEN_FOR_REPAIR) |
| 459 | { |
| 460 | myrg_print_wrong_table(myisam->filename); |
| 461 | bad_children= TRUE; |
| 462 | continue; |
| 463 | } |
| 464 | goto bad_children; |
| 465 | } |
| 466 | |
| 467 | m_info->options|= myisam->s->options; |
| 468 | m_info->records+= myisam->state->records; |
| 469 | m_info->del+= myisam->state->del; |
| 470 | m_info->data_file_length+= myisam->state->data_file_length; |
| 471 | if (min_keys > myisam->s->base.keys) |
| 472 | min_keys= myisam->s->base.keys; /* purecov: inspected */ |
| 473 | for (idx= 0; idx < key_parts; idx++) |
| 474 | m_info->rec_per_key_part[idx]+= (myisam->s->state.rec_per_key_part[idx] / |
| 475 | m_info->tables); |
| 476 | } |
| 477 | |
| 478 | if (bad_children) |
| 479 | goto bad_children; |
| 480 | |
| 481 | if (sizeof(my_off_t) == 4 && file_offset > (ulonglong) (ulong) ~0L) |
| 482 | { |
| 483 | my_errno= HA_ERR_RECORD_FILE_FULL; |
| 484 | goto err; |
| 485 | } |
| 486 | /* Don't mark table readonly, for ALTER TABLE ... UNION=(...) to work */ |
| 487 | m_info->options&= ~(HA_OPTION_COMPRESS_RECORD | HA_OPTION_READ_ONLY_DATA); |
| 488 | m_info->keys= min_keys; |
| 489 | m_info->last_used_table= m_info->open_tables; |
| 490 | m_info->children_attached= TRUE; |
| 491 | mysql_mutex_unlock(&m_info->mutex); |
| 492 | DBUG_RETURN(0); |
| 493 | |
| 494 | bad_children: |
| 495 | my_errno= HA_ERR_WRONG_MRG_TABLE_DEF; |
| 496 | err: |
| 497 | save_errno= my_errno; |
| 498 | switch (errpos) { |
| 499 | case 1: |
| 500 | my_free(m_info->rec_per_key_part); |
| 501 | m_info->rec_per_key_part= NULL; |
| 502 | } |
| 503 | mysql_mutex_unlock(&m_info->mutex); |
| 504 | my_errno= save_errno; |
| 505 | DBUG_RETURN(1); |
| 506 | } |
| 507 | |
| 508 | |
| 509 | /** |
| 510 | @brief Detach children from a MyISAM MERGE parent table. |
| 511 | |
| 512 | @param[in] m_info MERGE parent table structure |
| 513 | |
| 514 | @note Detach must not touch the children in any way. |
| 515 | They may have been closed at ths point already. |
| 516 | All references to the children should be removed. |
| 517 | |
| 518 | @return status |
| 519 | @retval 0 OK |
| 520 | */ |
| 521 | |
| 522 | int myrg_detach_children(MYRG_INFO *m_info) |
| 523 | { |
| 524 | DBUG_ENTER("myrg_detach_children" ); |
| 525 | /* For symmetry with myrg_attach_children() we use the mutex here. */ |
| 526 | mysql_mutex_lock(&m_info->mutex); |
| 527 | if (m_info->tables) |
| 528 | { |
| 529 | /* Do not attach/detach an empty child list. */ |
| 530 | m_info->children_attached= FALSE; |
| 531 | bzero((char*) m_info->open_tables, m_info->tables * sizeof(MYRG_TABLE)); |
| 532 | } |
| 533 | m_info->records= 0; |
| 534 | m_info->del= 0; |
| 535 | m_info->data_file_length= 0; |
| 536 | m_info->options= 0; |
| 537 | mysql_mutex_unlock(&m_info->mutex); |
| 538 | DBUG_RETURN(0); |
| 539 | } |
| 540 | |
| 541 | |