| 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 | |