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 1.23 2004/08/29 05:06:54 momjian Exp $
28 *-------------------------------------------------------------------------
40 #include "access/xlog.h"
41 #include "access/xlog_internal.h"
42 #include "catalog/catversion.h"
43 #include "catalog/pg_control.h"
48 #define _(x) gettext((x))
51 char XLogDir[MAXPGPATH]; /* not static, see xlog_internal.h */
52 static char ControlFilePath[MAXPGPATH];
54 static ControlFileData ControlFile; /* pg_control values */
55 static uint32 newXlogId,
56 newXlogSeg; /* ID/Segment of new XLOG segment */
57 static bool guessed = false; /* T if we had to guess at any values */
58 static const char *progname;
60 static bool ReadControlFile(void);
61 static void GuessControlValues(void);
62 static void PrintControlValues(bool guessed);
63 static void RewriteControlFile(void);
64 static void KillExistingXLOG(void);
65 static void WriteEmptyXLOG(void);
66 static void usage(void);
70 main(int argc, char *argv[])
74 bool noupdate = false;
75 TransactionId set_xid = 0;
85 set_pglocale_pgservice(argv[0], "pg_resetxlog");
87 progname = get_progname(argv[0]);
91 if (strcmp(argv[1], "--help") == 0 || strcmp(argv[1], "-?") == 0)
96 if (strcmp(argv[1], "--version") == 0 || strcmp(argv[1], "-V") == 0)
98 puts("pg_resetxlog (PostgreSQL) " PG_VERSION);
104 while ((c = getopt(argc, argv, "fl:no:x:")) != -1)
117 set_xid = strtoul(optarg, &endptr, 0);
118 if (endptr == optarg || *endptr != '\0')
120 fprintf(stderr, _("%s: invalid argument for option -x\n"), progname);
121 fprintf(stderr, _("Try \"%s --help\" for more information.\n"), progname);
126 fprintf(stderr, _("%s: transaction ID (-x) must not be 0\n"), progname);
132 set_oid = strtoul(optarg, &endptr, 0);
133 if (endptr == optarg || *endptr != '\0')
135 fprintf(stderr, _("%s: invalid argument for option -o\n"), progname);
136 fprintf(stderr, _("Try \"%s --help\" for more information.\n"), progname);
141 fprintf(stderr, _("%s: OID (-o) must not be 0\n"), progname);
147 minXlogId = strtoul(optarg, &endptr, 0);
148 if (endptr == optarg || *endptr != ',')
150 fprintf(stderr, _("%s: invalid argument for option -l\n"), progname);
151 fprintf(stderr, _("Try \"%s --help\" for more information.\n"), progname);
154 minXlogSeg = strtoul(endptr + 1, &endptr2, 0);
155 if (endptr2 == endptr + 1 || *endptr2 != '\0')
157 fprintf(stderr, _("%s: invalid argument for option -l\n"), progname);
158 fprintf(stderr, _("Try \"%s --help\" for more information.\n"), progname);
164 fprintf(stderr, _("Try \"%s --help\" for more information.\n"), progname);
171 fprintf(stderr, _("%s: no data directory specified\n"), progname);
172 fprintf(stderr, _("Try \"%s --help\" for more information.\n"), progname);
176 DataDir = argv[optind];
177 snprintf(XLogDir, MAXPGPATH, "%s/pg_xlog", DataDir);
178 snprintf(ControlFilePath, MAXPGPATH, "%s/global/pg_control", DataDir);
181 * Check for a postmaster lock file --- if there is one, refuse to
182 * proceed, on grounds we might be interfering with a live
185 snprintf(path, MAXPGPATH, "%s/postmaster.pid", DataDir);
187 if ((fd = open(path, O_RDONLY)) < 0)
191 fprintf(stderr, _("%s: could not open file \"%s\" for reading: %s\n"), progname, path, strerror(errno));
197 fprintf(stderr, _("%s: lock file \"%s\" exists\n"
198 "Is a server running? If not, delete the lock file and try again.\n"),
204 * Attempt to read the existing pg_control file
206 if (!ReadControlFile())
207 GuessControlValues();
210 * Adjust fields if required by switches. (Do this now so that
211 * printout, if any, includes these values.)
214 ControlFile.checkPointCopy.nextXid = set_xid;
217 ControlFile.checkPointCopy.nextOid = set_oid;
219 if (minXlogId > ControlFile.logId ||
220 (minXlogId == ControlFile.logId &&
221 minXlogSeg > ControlFile.logSeg))
223 ControlFile.logId = minXlogId;
224 ControlFile.logSeg = minXlogSeg;
228 * If we had to guess anything, and -f was not given, just print the
229 * guessed values and exit. Also print if -n is given.
231 if ((guessed && !force) || noupdate)
233 PrintControlValues(guessed);
236 printf(_("\nIf these values seem acceptable, use -f to force reset.\n"));
244 * Don't reset from a dirty pg_control without -f, either.
246 if (ControlFile.state != DB_SHUTDOWNED && !force)
248 printf(_("The database server was not shut down cleanly.\n"
249 "Resetting the transaction log may cause data to be lost.\n"
250 "If you want to proceed anyway, use -f to force reset.\n"));
255 * Else, do the dirty deed.
257 RewriteControlFile();
261 printf(_("Transaction log reset\n"));
267 * Try to read the existing pg_control file.
269 * This routine is also responsible for updating old pg_control versions
270 * to the current format. (Currently we don't do anything of the sort.)
273 ReadControlFile(void)
280 if ((fd = open(ControlFilePath, O_RDONLY)) < 0)
283 * If pg_control is not there at all, or we can't read it, the
284 * odds are we've been handed a bad DataDir path, so give up. User
285 * can do "touch pg_control" to force us to proceed.
287 fprintf(stderr, _("%s: could not open file \"%s\" for reading: %s\n"),
288 progname, ControlFilePath, strerror(errno));
290 fprintf(stderr, _("If you are sure the data directory path is correct, execute\n"
297 /* Use malloc to ensure we have a maxaligned buffer */
298 buffer = (char *) malloc(BLCKSZ);
300 len = read(fd, buffer, BLCKSZ);
303 fprintf(stderr, _("%s: could not read file \"%s\": %s\n"),
304 progname, ControlFilePath, strerror(errno));
309 if (len >= sizeof(ControlFileData) &&
310 ((ControlFileData *) buffer)->pg_control_version == PG_CONTROL_VERSION)
315 buffer + sizeof(crc64),
316 sizeof(ControlFileData) - sizeof(crc64));
319 if (EQ_CRC64(crc, ((ControlFileData *) buffer)->crc))
322 memcpy(&ControlFile, buffer, sizeof(ControlFile));
326 fprintf(stderr, _("%s: pg_control exists but has invalid CRC; proceed with caution\n"),
328 /* We will use the data anyway, but treat it as guessed. */
329 memcpy(&ControlFile, buffer, sizeof(ControlFile));
334 /* Looks like it's a mess. */
335 fprintf(stderr, _("%s: pg_control exists but is broken or unknown version; ignoring it\n"),
342 * Guess at pg_control values when we can't read the old ones.
345 GuessControlValues(void)
347 uint64 sysidentifier;
352 * Set up a completely default set of pg_control values.
355 memset(&ControlFile, 0, sizeof(ControlFile));
357 ControlFile.pg_control_version = PG_CONTROL_VERSION;
358 ControlFile.catalog_version_no = CATALOG_VERSION_NO;
361 * Create a new unique installation identifier, since we can no longer
362 * use any old XLOG records. See notes in xlog.c about the algorithm.
364 gettimeofday(&tv, NULL);
365 sysidentifier = ((uint64) tv.tv_sec) << 32;
366 sysidentifier |= (uint32) (tv.tv_sec | tv.tv_usec);
368 ControlFile.system_identifier = sysidentifier;
370 ControlFile.checkPointCopy.redo.xlogid = 0;
371 ControlFile.checkPointCopy.redo.xrecoff = SizeOfXLogLongPHD;
372 ControlFile.checkPointCopy.undo = ControlFile.checkPointCopy.redo;
373 ControlFile.checkPointCopy.ThisTimeLineID = 1;
374 ControlFile.checkPointCopy.nextXid = (TransactionId) 514; /* XXX */
375 ControlFile.checkPointCopy.nextOid = BootstrapObjectIdData;
376 ControlFile.checkPointCopy.time = time(NULL);
378 ControlFile.state = DB_SHUTDOWNED;
379 ControlFile.time = time(NULL);
380 ControlFile.logId = 0;
381 ControlFile.logSeg = 1;
382 ControlFile.checkPoint = ControlFile.checkPointCopy.redo;
384 ControlFile.blcksz = BLCKSZ;
385 ControlFile.relseg_size = RELSEG_SIZE;
386 ControlFile.xlog_seg_size = XLOG_SEG_SIZE;
387 ControlFile.nameDataLen = NAMEDATALEN;
388 ControlFile.funcMaxArgs = FUNC_MAX_ARGS;
389 #ifdef HAVE_INT64_TIMESTAMP
390 ControlFile.enableIntTimes = TRUE;
392 ControlFile.enableIntTimes = FALSE;
394 ControlFile.localeBuflen = LOCALE_NAME_BUFLEN;
396 localeptr = setlocale(LC_COLLATE, "");
399 fprintf(stderr, _("%s: invalid LC_COLLATE setting\n"), progname);
402 StrNCpy(ControlFile.lc_collate, localeptr, LOCALE_NAME_BUFLEN);
403 localeptr = setlocale(LC_CTYPE, "");
406 fprintf(stderr, _("%s: invalid LC_CTYPE setting\n"), progname);
409 StrNCpy(ControlFile.lc_ctype, localeptr, LOCALE_NAME_BUFLEN);
412 * XXX eventually, should try to grovel through old XLOG to develop
413 * more accurate values for TimeLineID, nextXID, and nextOID.
419 * Print the guessed pg_control values when we had to guess.
421 * NB: this display should be just those fields that will not be
422 * reset by RewriteControlFile().
425 PrintControlValues(bool guessed)
427 char sysident_str[32];
430 printf(_("Guessed pg_control values:\n\n"));
432 printf(_("pg_control values:\n\n"));
435 * Format system_identifier separately to keep platform-dependent
436 * format code out of the translatable message string.
438 snprintf(sysident_str, sizeof(sysident_str), UINT64_FORMAT,
439 ControlFile.system_identifier);
441 printf(_("pg_control version number: %u\n"), ControlFile.pg_control_version);
442 printf(_("Catalog version number: %u\n"), ControlFile.catalog_version_no);
443 printf(_("Database system identifier: %s\n"), sysident_str);
444 printf(_("Current log file ID: %u\n"), ControlFile.logId);
445 printf(_("Next log file segment: %u\n"), ControlFile.logSeg);
446 printf(_("Latest checkpoint's TimeLineID: %u\n"), ControlFile.checkPointCopy.ThisTimeLineID);
447 printf(_("Latest checkpoint's NextXID: %u\n"), ControlFile.checkPointCopy.nextXid);
448 printf(_("Latest checkpoint's NextOID: %u\n"), ControlFile.checkPointCopy.nextOid);
449 printf(_("Database block size: %u\n"), ControlFile.blcksz);
450 printf(_("Blocks per segment of large relation: %u\n"), ControlFile.relseg_size);
451 printf(_("Maximum length of identifiers: %u\n"), ControlFile.nameDataLen);
452 printf(_("Maximum number of function arguments: %u\n"), ControlFile.funcMaxArgs);
453 printf(_("Date/time type storage: %s\n"),
454 (ControlFile.enableIntTimes ? _("64-bit integers") : _("floating-point numbers")));
455 printf(_("Maximum length of locale name: %u\n"), ControlFile.localeBuflen);
456 printf(_("LC_COLLATE: %s\n"), ControlFile.lc_collate);
457 printf(_("LC_CTYPE: %s\n"), ControlFile.lc_ctype);
462 * Write out the new pg_control file.
465 RewriteControlFile(void)
468 char buffer[BLCKSZ]; /* need not be aligned */
471 * Adjust fields as needed to force an empty XLOG starting at the next
474 newXlogId = ControlFile.logId;
475 newXlogSeg = ControlFile.logSeg;
477 /* adjust in case we are changing segment size */
478 newXlogSeg *= ControlFile.xlog_seg_size;
479 newXlogSeg = (newXlogSeg + XLogSegSize - 1) / XLogSegSize;
481 /* be sure we wrap around correctly at end of a logfile */
482 NextLogSeg(newXlogId, newXlogSeg);
484 /* Now we can force the recorded xlog seg size to the right thing. */
485 ControlFile.xlog_seg_size = XLogSegSize;
487 ControlFile.checkPointCopy.redo.xlogid = newXlogId;
488 ControlFile.checkPointCopy.redo.xrecoff =
489 newXlogSeg * XLogSegSize + SizeOfXLogLongPHD;
490 ControlFile.checkPointCopy.undo = ControlFile.checkPointCopy.redo;
491 ControlFile.checkPointCopy.time = time(NULL);
493 ControlFile.state = DB_SHUTDOWNED;
494 ControlFile.time = time(NULL);
495 ControlFile.logId = newXlogId;
496 ControlFile.logSeg = newXlogSeg + 1;
497 ControlFile.checkPoint = ControlFile.checkPointCopy.redo;
498 ControlFile.prevCheckPoint.xlogid = 0;
499 ControlFile.prevCheckPoint.xrecoff = 0;
501 /* Contents are protected with a CRC */
502 INIT_CRC64(ControlFile.crc);
503 COMP_CRC64(ControlFile.crc,
504 (char *) &ControlFile + sizeof(crc64),
505 sizeof(ControlFileData) - sizeof(crc64));
506 FIN_CRC64(ControlFile.crc);
509 * We write out BLCKSZ bytes into pg_control, zero-padding the excess
510 * over sizeof(ControlFileData). This reduces the odds of
511 * premature-EOF errors when reading pg_control. We'll still fail
512 * when we check the contents of the file, but hopefully with a more
513 * specific error than "couldn't read pg_control".
515 if (sizeof(ControlFileData) > BLCKSZ)
518 _("%s: internal error -- sizeof(ControlFileData) is too large ... fix xlog.c\n"),
523 memset(buffer, 0, BLCKSZ);
524 memcpy(buffer, &ControlFile, sizeof(ControlFileData));
526 unlink(ControlFilePath);
528 fd = open(ControlFilePath, O_RDWR | O_CREAT | O_EXCL | PG_BINARY, S_IRUSR | S_IWUSR);
531 fprintf(stderr, _("%s: could not create pg_control file: %s\n"),
532 progname, strerror(errno));
537 if (write(fd, buffer, BLCKSZ) != BLCKSZ)
539 /* if write didn't set errno, assume problem is no disk space */
542 fprintf(stderr, _("%s: could not write pg_control file: %s\n"),
543 progname, strerror(errno));
549 fprintf(stderr, _("%s: fsync error: %s\n"), progname, strerror(errno));
558 * Remove existing XLOG files
561 KillExistingXLOG(void)
565 char path[MAXPGPATH];
567 xldir = opendir(XLogDir);
570 fprintf(stderr, _("%s: could not open directory \"%s\": %s\n"),
571 progname, XLogDir, strerror(errno));
576 while ((xlde = readdir(xldir)) != NULL)
578 if (strlen(xlde->d_name) == 16 &&
579 strspn(xlde->d_name, "0123456789ABCDEF") == 16)
581 snprintf(path, MAXPGPATH, "%s/%s", XLogDir, xlde->d_name);
582 if (unlink(path) < 0)
584 fprintf(stderr, _("%s: could not delete file \"%s\": %s\n"),
585 progname, path, strerror(errno));
594 * This fix is in mingw cvs (runtime/mingwex/dirent.c rev 1.4), but
595 * not in released version
597 if (GetLastError() == ERROR_NO_MORE_FILES)
603 fprintf(stderr, _("%s: could not read from directory \"%s\": %s\n"),
604 progname, XLogDir, strerror(errno));
612 * Write an empty XLOG file, containing only the checkpoint record
613 * already set up in ControlFile.
620 XLogLongPageHeader longpage;
623 char path[MAXPGPATH];
627 /* Use malloc() to ensure buffer is MAXALIGNED */
628 buffer = (char *) malloc(BLCKSZ);
629 page = (XLogPageHeader) buffer;
630 memset(buffer, 0, BLCKSZ);
632 /* Set up the XLOG page header */
633 page->xlp_magic = XLOG_PAGE_MAGIC;
634 page->xlp_info = XLP_LONG_HEADER;
635 page->xlp_tli = ControlFile.checkPointCopy.ThisTimeLineID;
636 page->xlp_pageaddr.xlogid =
637 ControlFile.checkPointCopy.redo.xlogid;
638 page->xlp_pageaddr.xrecoff =
639 ControlFile.checkPointCopy.redo.xrecoff - SizeOfXLogLongPHD;
640 longpage = (XLogLongPageHeader) page;
641 longpage->xlp_sysid = ControlFile.system_identifier;
642 longpage->xlp_seg_size = XLogSegSize;
644 /* Insert the initial checkpoint record */
645 record = (XLogRecord *) ((char *) page + SizeOfXLogLongPHD);
646 record->xl_prev.xlogid = 0;
647 record->xl_prev.xrecoff = 0;
648 record->xl_xact_prev.xlogid = 0;
649 record->xl_xact_prev.xrecoff = 0;
650 record->xl_xid = InvalidTransactionId;
651 record->xl_len = sizeof(CheckPoint);
652 record->xl_info = XLOG_CHECKPOINT_SHUTDOWN;
653 record->xl_rmid = RM_XLOG_ID;
654 memcpy(XLogRecGetData(record), &ControlFile.checkPointCopy,
658 COMP_CRC64(crc, &ControlFile.checkPointCopy, sizeof(CheckPoint));
659 COMP_CRC64(crc, (char *) record + sizeof(crc64),
660 SizeOfXLogRecord - sizeof(crc64));
662 record->xl_crc = crc;
664 /* Write the first page */
665 XLogFilePath(path, ControlFile.checkPointCopy.ThisTimeLineID,
666 newXlogId, newXlogSeg);
670 fd = open(path, O_RDWR | O_CREAT | O_EXCL | PG_BINARY,
674 fprintf(stderr, _("%s: could not open file \"%s\": %s\n"),
675 progname, path, strerror(errno));
680 if (write(fd, buffer, BLCKSZ) != BLCKSZ)
682 /* if write didn't set errno, assume problem is no disk space */
685 fprintf(stderr, _("%s: could not write file \"%s\": %s\n"),
686 progname, path, strerror(errno));
690 /* Fill the rest of the file with zeroes */
691 memset(buffer, 0, BLCKSZ);
692 for (nbytes = BLCKSZ; nbytes < XLogSegSize; nbytes += BLCKSZ)
695 if (write(fd, buffer, BLCKSZ) != BLCKSZ)
699 fprintf(stderr, _("%s: could not write file \"%s\": %s\n"),
700 progname, path, strerror(errno));
707 fprintf(stderr, _("%s: fsync error: %s\n"), progname, strerror(errno));
718 printf(_("%s resets the PostgreSQL transaction log.\n\n"), progname);
719 printf(_("Usage:\n %s [OPTION]... DATADIR\n\n"), progname);
720 printf(_("Options:\n"));
721 printf(_(" -f force update to be done\n"));
722 printf(_(" -l FILEID,SEG force minimum WAL starting location for new transaction log\n"));
723 printf(_(" -n no update, just show extracted control values (for testing)\n"));
724 printf(_(" -o OID set next OID\n"));
725 printf(_(" -x XID set next transaction ID\n"));
726 printf(_(" --help show this help, then exit\n"));
727 printf(_(" --version output version information, then exit\n"));
728 printf(_("\nReport bugs to <pgsql-bugs@postgresql.org>.\n"));