1 /*-------------------------------------------------------------------------
4 * A utility to "zero out" the xlog when it's corrupt beyond recovery.
5 * Can also rebuild pg_control if needed.
7 * The theory of operation is fairly simple:
8 * 1. Read the existing pg_control (which will include the last
9 * checkpoint record). If it is an old format then update to
11 * 2. If pg_control is corrupt, attempt to intuit reasonable values,
12 * by scanning the old xlog if necessary.
13 * 3. Modify pg_control to reflect a "shutdown" state with a checkpoint
14 * record at the start of xlog.
15 * 4. Flush the existing xlog files and write a new segment with
16 * just a checkpoint record in it. The new segment is positioned
17 * just past the end of the old xlog, so that existing LSNs in
18 * data pages will appear to be "in the past".
19 * This is all pretty straightforward except for the intuition part of
23 * Portions Copyright (c) 1996-2004, PostgreSQL Global Development Group
24 * Portions Copyright (c) 1994, Regents of the University of California
26 * $PostgreSQL: pgsql/src/bin/pg_resetxlog/pg_resetxlog.c,v 1.25 2004/11/17 21:37:47 tgl Exp $
28 *-------------------------------------------------------------------------
43 #include "access/xlog.h"
44 #include "access/xlog_internal.h"
45 #include "catalog/catversion.h"
46 #include "catalog/pg_control.h"
51 #define _(x) gettext((x))
54 char XLogDir[MAXPGPATH]; /* not static, see xlog_internal.h */
55 static char ControlFilePath[MAXPGPATH];
57 static ControlFileData ControlFile; /* pg_control values */
58 static uint32 newXlogId,
59 newXlogSeg; /* ID/Segment of new XLOG segment */
60 static bool guessed = false; /* T if we had to guess at any values */
61 static const char *progname;
63 static bool ReadControlFile(void);
64 static void GuessControlValues(void);
65 static void PrintControlValues(bool guessed);
66 static void RewriteControlFile(void);
67 static void KillExistingXLOG(void);
68 static void WriteEmptyXLOG(void);
69 static void usage(void);
73 main(int argc, char *argv[])
77 bool noupdate = false;
78 TransactionId set_xid = 0;
88 set_pglocale_pgservice(argv[0], "pg_resetxlog");
90 progname = get_progname(argv[0]);
94 if (strcmp(argv[1], "--help") == 0 || strcmp(argv[1], "-?") == 0)
99 if (strcmp(argv[1], "--version") == 0 || strcmp(argv[1], "-V") == 0)
101 puts("pg_resetxlog (PostgreSQL) " PG_VERSION);
107 while ((c = getopt(argc, argv, "fl:no:x:")) != -1)
120 set_xid = strtoul(optarg, &endptr, 0);
121 if (endptr == optarg || *endptr != '\0')
123 fprintf(stderr, _("%s: invalid argument for option -x\n"), progname);
124 fprintf(stderr, _("Try \"%s --help\" for more information.\n"), progname);
129 fprintf(stderr, _("%s: transaction ID (-x) must not be 0\n"), progname);
135 set_oid = strtoul(optarg, &endptr, 0);
136 if (endptr == optarg || *endptr != '\0')
138 fprintf(stderr, _("%s: invalid argument for option -o\n"), progname);
139 fprintf(stderr, _("Try \"%s --help\" for more information.\n"), progname);
144 fprintf(stderr, _("%s: OID (-o) must not be 0\n"), progname);
150 minXlogId = strtoul(optarg, &endptr, 0);
151 if (endptr == optarg || *endptr != ',')
153 fprintf(stderr, _("%s: invalid argument for option -l\n"), progname);
154 fprintf(stderr, _("Try \"%s --help\" for more information.\n"), progname);
157 minXlogSeg = strtoul(endptr + 1, &endptr2, 0);
158 if (endptr2 == endptr + 1 || *endptr2 != '\0')
160 fprintf(stderr, _("%s: invalid argument for option -l\n"), progname);
161 fprintf(stderr, _("Try \"%s --help\" for more information.\n"), progname);
167 fprintf(stderr, _("Try \"%s --help\" for more information.\n"), progname);
174 fprintf(stderr, _("%s: no data directory specified\n"), progname);
175 fprintf(stderr, _("Try \"%s --help\" for more information.\n"), progname);
179 DataDir = argv[optind];
180 snprintf(XLogDir, MAXPGPATH, "%s/pg_xlog", DataDir);
181 snprintf(ControlFilePath, MAXPGPATH, "%s/global/pg_control", DataDir);
184 * Check for a postmaster lock file --- if there is one, refuse to
185 * proceed, on grounds we might be interfering with a live
188 snprintf(path, MAXPGPATH, "%s/postmaster.pid", DataDir);
190 if ((fd = open(path, O_RDONLY)) < 0)
194 fprintf(stderr, _("%s: could not open file \"%s\" for reading: %s\n"), progname, path, strerror(errno));
200 fprintf(stderr, _("%s: lock file \"%s\" exists\n"
201 "Is a server running? If not, delete the lock file and try again.\n"),
207 * Attempt to read the existing pg_control file
209 if (!ReadControlFile())
210 GuessControlValues();
213 * Adjust fields if required by switches. (Do this now so that
214 * printout, if any, includes these values.)
217 ControlFile.checkPointCopy.nextXid = set_xid;
220 ControlFile.checkPointCopy.nextOid = set_oid;
222 if (minXlogId > ControlFile.logId ||
223 (minXlogId == ControlFile.logId &&
224 minXlogSeg > ControlFile.logSeg))
226 ControlFile.logId = minXlogId;
227 ControlFile.logSeg = minXlogSeg;
231 * If we had to guess anything, and -f was not given, just print the
232 * guessed values and exit. Also print if -n is given.
234 if ((guessed && !force) || noupdate)
236 PrintControlValues(guessed);
239 printf(_("\nIf these values seem acceptable, use -f to force reset.\n"));
247 * Don't reset from a dirty pg_control without -f, either.
249 if (ControlFile.state != DB_SHUTDOWNED && !force)
251 printf(_("The database server was not shut down cleanly.\n"
252 "Resetting the transaction log may cause data to be lost.\n"
253 "If you want to proceed anyway, use -f to force reset.\n"));
258 * Else, do the dirty deed.
260 RewriteControlFile();
264 printf(_("Transaction log reset\n"));
270 * Try to read the existing pg_control file.
272 * This routine is also responsible for updating old pg_control versions
273 * to the current format. (Currently we don't do anything of the sort.)
276 ReadControlFile(void)
283 if ((fd = open(ControlFilePath, O_RDONLY)) < 0)
286 * If pg_control is not there at all, or we can't read it, the
287 * odds are we've been handed a bad DataDir path, so give up. User
288 * can do "touch pg_control" to force us to proceed.
290 fprintf(stderr, _("%s: could not open file \"%s\" for reading: %s\n"),
291 progname, ControlFilePath, strerror(errno));
293 fprintf(stderr, _("If you are sure the data directory path is correct, execute\n"
300 /* Use malloc to ensure we have a maxaligned buffer */
301 buffer = (char *) malloc(BLCKSZ);
303 len = read(fd, buffer, BLCKSZ);
306 fprintf(stderr, _("%s: could not read file \"%s\": %s\n"),
307 progname, ControlFilePath, strerror(errno));
312 if (len >= sizeof(ControlFileData) &&
313 ((ControlFileData *) buffer)->pg_control_version == PG_CONTROL_VERSION)
318 buffer + sizeof(crc64),
319 sizeof(ControlFileData) - sizeof(crc64));
322 if (EQ_CRC64(crc, ((ControlFileData *) buffer)->crc))
325 memcpy(&ControlFile, buffer, sizeof(ControlFile));
329 fprintf(stderr, _("%s: pg_control exists but has invalid CRC; proceed with caution\n"),
331 /* We will use the data anyway, but treat it as guessed. */
332 memcpy(&ControlFile, buffer, sizeof(ControlFile));
337 /* Looks like it's a mess. */
338 fprintf(stderr, _("%s: pg_control exists but is broken or unknown version; ignoring it\n"),
345 * Guess at pg_control values when we can't read the old ones.
348 GuessControlValues(void)
350 uint64 sysidentifier;
355 * Set up a completely default set of pg_control values.
358 memset(&ControlFile, 0, sizeof(ControlFile));
360 ControlFile.pg_control_version = PG_CONTROL_VERSION;
361 ControlFile.catalog_version_no = CATALOG_VERSION_NO;
364 * Create a new unique installation identifier, since we can no longer
365 * use any old XLOG records. See notes in xlog.c about the algorithm.
367 gettimeofday(&tv, NULL);
368 sysidentifier = ((uint64) tv.tv_sec) << 32;
369 sysidentifier |= (uint32) (tv.tv_sec | tv.tv_usec);
371 ControlFile.system_identifier = sysidentifier;
373 ControlFile.checkPointCopy.redo.xlogid = 0;
374 ControlFile.checkPointCopy.redo.xrecoff = SizeOfXLogLongPHD;
375 ControlFile.checkPointCopy.undo = ControlFile.checkPointCopy.redo;
376 ControlFile.checkPointCopy.ThisTimeLineID = 1;
377 ControlFile.checkPointCopy.nextXid = (TransactionId) 514; /* XXX */
378 ControlFile.checkPointCopy.nextOid = BootstrapObjectIdData;
379 ControlFile.checkPointCopy.time = time(NULL);
381 ControlFile.state = DB_SHUTDOWNED;
382 ControlFile.time = time(NULL);
383 ControlFile.logId = 0;
384 ControlFile.logSeg = 1;
385 ControlFile.checkPoint = ControlFile.checkPointCopy.redo;
387 ControlFile.blcksz = BLCKSZ;
388 ControlFile.relseg_size = RELSEG_SIZE;
389 ControlFile.xlog_seg_size = XLOG_SEG_SIZE;
390 ControlFile.nameDataLen = NAMEDATALEN;
391 ControlFile.funcMaxArgs = FUNC_MAX_ARGS;
392 #ifdef HAVE_INT64_TIMESTAMP
393 ControlFile.enableIntTimes = TRUE;
395 ControlFile.enableIntTimes = FALSE;
397 ControlFile.localeBuflen = LOCALE_NAME_BUFLEN;
399 localeptr = setlocale(LC_COLLATE, "");
402 fprintf(stderr, _("%s: invalid LC_COLLATE setting\n"), progname);
405 StrNCpy(ControlFile.lc_collate, localeptr, LOCALE_NAME_BUFLEN);
406 localeptr = setlocale(LC_CTYPE, "");
409 fprintf(stderr, _("%s: invalid LC_CTYPE setting\n"), progname);
412 StrNCpy(ControlFile.lc_ctype, localeptr, LOCALE_NAME_BUFLEN);
415 * XXX eventually, should try to grovel through old XLOG to develop
416 * more accurate values for TimeLineID, nextXID, and nextOID.
422 * Print the guessed pg_control values when we had to guess.
424 * NB: this display should be just those fields that will not be
425 * reset by RewriteControlFile().
428 PrintControlValues(bool guessed)
430 char sysident_str[32];
433 printf(_("Guessed pg_control values:\n\n"));
435 printf(_("pg_control values:\n\n"));
438 * Format system_identifier separately to keep platform-dependent
439 * format code out of the translatable message string.
441 snprintf(sysident_str, sizeof(sysident_str), UINT64_FORMAT,
442 ControlFile.system_identifier);
444 printf(_("pg_control version number: %u\n"), ControlFile.pg_control_version);
445 printf(_("Catalog version number: %u\n"), ControlFile.catalog_version_no);
446 printf(_("Database system identifier: %s\n"), sysident_str);
447 printf(_("Current log file ID: %u\n"), ControlFile.logId);
448 printf(_("Next log file segment: %u\n"), ControlFile.logSeg);
449 printf(_("Latest checkpoint's TimeLineID: %u\n"), ControlFile.checkPointCopy.ThisTimeLineID);
450 printf(_("Latest checkpoint's NextXID: %u\n"), ControlFile.checkPointCopy.nextXid);
451 printf(_("Latest checkpoint's NextOID: %u\n"), ControlFile.checkPointCopy.nextOid);
452 printf(_("Database block size: %u\n"), ControlFile.blcksz);
453 printf(_("Blocks per segment of large relation: %u\n"), ControlFile.relseg_size);
454 printf(_("Maximum length of identifiers: %u\n"), ControlFile.nameDataLen);
455 printf(_("Maximum number of function arguments: %u\n"), ControlFile.funcMaxArgs);
456 printf(_("Date/time type storage: %s\n"),
457 (ControlFile.enableIntTimes ? _("64-bit integers") : _("floating-point numbers")));
458 printf(_("Maximum length of locale name: %u\n"), ControlFile.localeBuflen);
459 printf(_("LC_COLLATE: %s\n"), ControlFile.lc_collate);
460 printf(_("LC_CTYPE: %s\n"), ControlFile.lc_ctype);
465 * Write out the new pg_control file.
468 RewriteControlFile(void)
471 char buffer[BLCKSZ]; /* need not be aligned */
474 * Adjust fields as needed to force an empty XLOG starting at the next
477 newXlogId = ControlFile.logId;
478 newXlogSeg = ControlFile.logSeg;
480 /* adjust in case we are changing segment size */
481 newXlogSeg *= ControlFile.xlog_seg_size;
482 newXlogSeg = (newXlogSeg + XLogSegSize - 1) / XLogSegSize;
484 /* be sure we wrap around correctly at end of a logfile */
485 NextLogSeg(newXlogId, newXlogSeg);
487 /* Now we can force the recorded xlog seg size to the right thing. */
488 ControlFile.xlog_seg_size = XLogSegSize;
490 ControlFile.checkPointCopy.redo.xlogid = newXlogId;
491 ControlFile.checkPointCopy.redo.xrecoff =
492 newXlogSeg * XLogSegSize + SizeOfXLogLongPHD;
493 ControlFile.checkPointCopy.undo = ControlFile.checkPointCopy.redo;
494 ControlFile.checkPointCopy.time = time(NULL);
496 ControlFile.state = DB_SHUTDOWNED;
497 ControlFile.time = time(NULL);
498 ControlFile.logId = newXlogId;
499 ControlFile.logSeg = newXlogSeg + 1;
500 ControlFile.checkPoint = ControlFile.checkPointCopy.redo;
501 ControlFile.prevCheckPoint.xlogid = 0;
502 ControlFile.prevCheckPoint.xrecoff = 0;
504 /* Contents are protected with a CRC */
505 INIT_CRC64(ControlFile.crc);
506 COMP_CRC64(ControlFile.crc,
507 (char *) &ControlFile + sizeof(crc64),
508 sizeof(ControlFileData) - sizeof(crc64));
509 FIN_CRC64(ControlFile.crc);
512 * We write out BLCKSZ bytes into pg_control, zero-padding the excess
513 * over sizeof(ControlFileData). This reduces the odds of
514 * premature-EOF errors when reading pg_control. We'll still fail
515 * when we check the contents of the file, but hopefully with a more
516 * specific error than "couldn't read pg_control".
518 if (sizeof(ControlFileData) > BLCKSZ)
521 _("%s: internal error -- sizeof(ControlFileData) is too large ... fix xlog.c\n"),
526 memset(buffer, 0, BLCKSZ);
527 memcpy(buffer, &ControlFile, sizeof(ControlFileData));
529 unlink(ControlFilePath);
531 fd = open(ControlFilePath, O_RDWR | O_CREAT | O_EXCL | PG_BINARY, S_IRUSR | S_IWUSR);
534 fprintf(stderr, _("%s: could not create pg_control file: %s\n"),
535 progname, strerror(errno));
540 if (write(fd, buffer, BLCKSZ) != BLCKSZ)
542 /* if write didn't set errno, assume problem is no disk space */
545 fprintf(stderr, _("%s: could not write pg_control file: %s\n"),
546 progname, strerror(errno));
552 fprintf(stderr, _("%s: fsync error: %s\n"), progname, strerror(errno));
561 * Remove existing XLOG files
564 KillExistingXLOG(void)
568 char path[MAXPGPATH];
570 xldir = opendir(XLogDir);
573 fprintf(stderr, _("%s: could not open directory \"%s\": %s\n"),
574 progname, XLogDir, strerror(errno));
579 while ((xlde = readdir(xldir)) != NULL)
581 if (strlen(xlde->d_name) == 16 &&
582 strspn(xlde->d_name, "0123456789ABCDEF") == 16)
584 snprintf(path, MAXPGPATH, "%s/%s", XLogDir, xlde->d_name);
585 if (unlink(path) < 0)
587 fprintf(stderr, _("%s: could not delete file \"%s\": %s\n"),
588 progname, path, strerror(errno));
597 * This fix is in mingw cvs (runtime/mingwex/dirent.c rev 1.4), but
598 * not in released version
600 if (GetLastError() == ERROR_NO_MORE_FILES)
606 fprintf(stderr, _("%s: could not read from directory \"%s\": %s\n"),
607 progname, XLogDir, strerror(errno));
615 * Write an empty XLOG file, containing only the checkpoint record
616 * already set up in ControlFile.
623 XLogLongPageHeader longpage;
626 char path[MAXPGPATH];
630 /* Use malloc() to ensure buffer is MAXALIGNED */
631 buffer = (char *) malloc(BLCKSZ);
632 page = (XLogPageHeader) buffer;
633 memset(buffer, 0, BLCKSZ);
635 /* Set up the XLOG page header */
636 page->xlp_magic = XLOG_PAGE_MAGIC;
637 page->xlp_info = XLP_LONG_HEADER;
638 page->xlp_tli = ControlFile.checkPointCopy.ThisTimeLineID;
639 page->xlp_pageaddr.xlogid =
640 ControlFile.checkPointCopy.redo.xlogid;
641 page->xlp_pageaddr.xrecoff =
642 ControlFile.checkPointCopy.redo.xrecoff - SizeOfXLogLongPHD;
643 longpage = (XLogLongPageHeader) page;
644 longpage->xlp_sysid = ControlFile.system_identifier;
645 longpage->xlp_seg_size = XLogSegSize;
647 /* Insert the initial checkpoint record */
648 record = (XLogRecord *) ((char *) page + SizeOfXLogLongPHD);
649 record->xl_prev.xlogid = 0;
650 record->xl_prev.xrecoff = 0;
651 record->xl_xid = InvalidTransactionId;
652 record->xl_len = sizeof(CheckPoint);
653 record->xl_info = XLOG_CHECKPOINT_SHUTDOWN;
654 record->xl_rmid = RM_XLOG_ID;
655 memcpy(XLogRecGetData(record), &ControlFile.checkPointCopy,
659 COMP_CRC64(crc, &ControlFile.checkPointCopy, sizeof(CheckPoint));
660 COMP_CRC64(crc, (char *) record + sizeof(crc64),
661 SizeOfXLogRecord - sizeof(crc64));
663 record->xl_crc = crc;
665 /* Write the first page */
666 XLogFilePath(path, ControlFile.checkPointCopy.ThisTimeLineID,
667 newXlogId, newXlogSeg);
671 fd = open(path, O_RDWR | O_CREAT | O_EXCL | PG_BINARY,
675 fprintf(stderr, _("%s: could not open file \"%s\": %s\n"),
676 progname, path, strerror(errno));
681 if (write(fd, buffer, BLCKSZ) != BLCKSZ)
683 /* if write didn't set errno, assume problem is no disk space */
686 fprintf(stderr, _("%s: could not write file \"%s\": %s\n"),
687 progname, path, strerror(errno));
691 /* Fill the rest of the file with zeroes */
692 memset(buffer, 0, BLCKSZ);
693 for (nbytes = BLCKSZ; nbytes < XLogSegSize; nbytes += BLCKSZ)
696 if (write(fd, buffer, BLCKSZ) != BLCKSZ)
700 fprintf(stderr, _("%s: could not write file \"%s\": %s\n"),
701 progname, path, strerror(errno));
708 fprintf(stderr, _("%s: fsync error: %s\n"), progname, strerror(errno));
719 printf(_("%s resets the PostgreSQL transaction log.\n\n"), progname);
720 printf(_("Usage:\n %s [OPTION]... DATADIR\n\n"), progname);
721 printf(_("Options:\n"));
722 printf(_(" -f force update to be done\n"));
723 printf(_(" -l FILEID,SEG force minimum WAL starting location for new transaction log\n"));
724 printf(_(" -n no update, just show extracted control values (for testing)\n"));
725 printf(_(" -o OID set next OID\n"));
726 printf(_(" -x XID set next transaction ID\n"));
727 printf(_(" --help show this help, then exit\n"));
728 printf(_(" --version output version information, then exit\n"));
729 printf(_("\nReport bugs to <pgsql-bugs@postgresql.org>.\n"));