871 lines
24 KiB
C
871 lines
24 KiB
C
/*-------------------------------------------------------------------------
|
|
*
|
|
* pg_rewind.c
|
|
* Synchronizes a PostgreSQL data directory to a new timeline
|
|
*
|
|
* Portions Copyright (c) 1996-2020, PostgreSQL Global Development Group
|
|
*
|
|
*-------------------------------------------------------------------------
|
|
*/
|
|
#include "postgres_fe.h"
|
|
|
|
#include <sys/stat.h>
|
|
#include <fcntl.h>
|
|
#include <time.h>
|
|
#include <unistd.h>
|
|
|
|
#include "access/timeline.h"
|
|
#include "access/xlog_internal.h"
|
|
#include "catalog/catversion.h"
|
|
#include "catalog/pg_control.h"
|
|
#include "common/controldata_utils.h"
|
|
#include "common/file_perm.h"
|
|
#include "common/file_utils.h"
|
|
#include "common/restricted_token.h"
|
|
#include "fe_utils/recovery_gen.h"
|
|
#include "fetch.h"
|
|
#include "file_ops.h"
|
|
#include "filemap.h"
|
|
#include "getopt_long.h"
|
|
#include "pg_rewind.h"
|
|
#include "storage/bufpage.h"
|
|
|
|
static void usage(const char *progname);
|
|
|
|
static void createBackupLabel(XLogRecPtr startpoint, TimeLineID starttli,
|
|
XLogRecPtr checkpointloc);
|
|
|
|
static void digestControlFile(ControlFileData *ControlFile, char *source,
|
|
size_t size);
|
|
static void syncTargetDirectory(void);
|
|
static void sanityChecks(void);
|
|
static void findCommonAncestorTimeline(XLogRecPtr *recptr, int *tliIndex);
|
|
static void ensureCleanShutdown(const char *argv0);
|
|
static void disconnect_atexit(void);
|
|
|
|
static ControlFileData ControlFile_target;
|
|
static ControlFileData ControlFile_source;
|
|
|
|
const char *progname;
|
|
int WalSegSz;
|
|
|
|
/* Configuration options */
|
|
char *datadir_target = NULL;
|
|
char *datadir_source = NULL;
|
|
char *connstr_source = NULL;
|
|
|
|
static bool debug = false;
|
|
bool showprogress = false;
|
|
bool dry_run = false;
|
|
bool do_sync = true;
|
|
|
|
/* Target history */
|
|
TimeLineHistoryEntry *targetHistory;
|
|
int targetNentries;
|
|
|
|
/* Progress counters */
|
|
uint64 fetch_size;
|
|
uint64 fetch_done;
|
|
|
|
|
|
static void
|
|
usage(const char *progname)
|
|
{
|
|
printf(_("%s resynchronizes a PostgreSQL cluster with another copy of the cluster.\n\n"), progname);
|
|
printf(_("Usage:\n %s [OPTION]...\n\n"), progname);
|
|
printf(_("Options:\n"));
|
|
printf(_(" -D, --target-pgdata=DIRECTORY existing data directory to modify\n"));
|
|
printf(_(" --source-pgdata=DIRECTORY source data directory to synchronize with\n"));
|
|
printf(_(" --source-server=CONNSTR source server to synchronize with\n"));
|
|
printf(_(" -R, --write-recovery-conf write configuration for replication\n"
|
|
" (requires --source-server)\n"));
|
|
printf(_(" -n, --dry-run stop before modifying anything\n"));
|
|
printf(_(" -N, --no-sync do not wait for changes to be written\n"
|
|
" safely to disk\n"));
|
|
printf(_(" -P, --progress write progress messages\n"));
|
|
printf(_(" --no-ensure-shutdown do not automatically fix unclean shutdown\n"));
|
|
printf(_(" --debug write a lot of debug messages\n"));
|
|
printf(_(" -V, --version output version information, then exit\n"));
|
|
printf(_(" -?, --help show this help, then exit\n"));
|
|
printf(_("\nReport bugs to <%s>.\n"), PACKAGE_BUGREPORT);
|
|
}
|
|
|
|
|
|
int
|
|
main(int argc, char **argv)
|
|
{
|
|
static struct option long_options[] = {
|
|
{"help", no_argument, NULL, '?'},
|
|
{"target-pgdata", required_argument, NULL, 'D'},
|
|
{"write-recovery-conf", no_argument, NULL, 'R'},
|
|
{"source-pgdata", required_argument, NULL, 1},
|
|
{"source-server", required_argument, NULL, 2},
|
|
{"no-ensure-shutdown", no_argument, NULL, 4},
|
|
{"version", no_argument, NULL, 'V'},
|
|
{"dry-run", no_argument, NULL, 'n'},
|
|
{"no-sync", no_argument, NULL, 'N'},
|
|
{"progress", no_argument, NULL, 'P'},
|
|
{"debug", no_argument, NULL, 3},
|
|
{NULL, 0, NULL, 0}
|
|
};
|
|
int option_index;
|
|
int c;
|
|
XLogRecPtr divergerec;
|
|
int lastcommontliIndex;
|
|
XLogRecPtr chkptrec;
|
|
TimeLineID chkpttli;
|
|
XLogRecPtr chkptredo;
|
|
size_t size;
|
|
char *buffer;
|
|
bool no_ensure_shutdown = false;
|
|
bool rewind_needed;
|
|
XLogRecPtr endrec;
|
|
TimeLineID endtli;
|
|
ControlFileData ControlFile_new;
|
|
bool writerecoveryconf = false;
|
|
|
|
pg_logging_init(argv[0]);
|
|
set_pglocale_pgservice(argv[0], PG_TEXTDOMAIN("pg_rewind"));
|
|
progname = get_progname(argv[0]);
|
|
|
|
/* Process command-line arguments */
|
|
if (argc > 1)
|
|
{
|
|
if (strcmp(argv[1], "--help") == 0 || strcmp(argv[1], "-?") == 0)
|
|
{
|
|
usage(progname);
|
|
exit(0);
|
|
}
|
|
if (strcmp(argv[1], "--version") == 0 || strcmp(argv[1], "-V") == 0)
|
|
{
|
|
puts("pg_rewind (PostgreSQL) " PG_VERSION);
|
|
exit(0);
|
|
}
|
|
}
|
|
|
|
while ((c = getopt_long(argc, argv, "D:nNPR", long_options, &option_index)) != -1)
|
|
{
|
|
switch (c)
|
|
{
|
|
case '?':
|
|
fprintf(stderr, _("Try \"%s --help\" for more information.\n"), progname);
|
|
exit(1);
|
|
|
|
case 'P':
|
|
showprogress = true;
|
|
break;
|
|
|
|
case 'n':
|
|
dry_run = true;
|
|
break;
|
|
|
|
case 'N':
|
|
do_sync = false;
|
|
break;
|
|
|
|
case 'R':
|
|
writerecoveryconf = true;
|
|
break;
|
|
|
|
case 3:
|
|
debug = true;
|
|
pg_logging_set_level(PG_LOG_DEBUG);
|
|
break;
|
|
|
|
case 'D': /* -D or --target-pgdata */
|
|
datadir_target = pg_strdup(optarg);
|
|
break;
|
|
|
|
case 1: /* --source-pgdata */
|
|
datadir_source = pg_strdup(optarg);
|
|
break;
|
|
|
|
case 2: /* --source-server */
|
|
connstr_source = pg_strdup(optarg);
|
|
break;
|
|
|
|
case 4:
|
|
no_ensure_shutdown = true;
|
|
break;
|
|
}
|
|
}
|
|
|
|
if (datadir_source == NULL && connstr_source == NULL)
|
|
{
|
|
pg_log_error("no source specified (--source-pgdata or --source-server)");
|
|
fprintf(stderr, _("Try \"%s --help\" for more information.\n"), progname);
|
|
exit(1);
|
|
}
|
|
|
|
if (datadir_source != NULL && connstr_source != NULL)
|
|
{
|
|
pg_log_error("only one of --source-pgdata or --source-server can be specified");
|
|
fprintf(stderr, _("Try \"%s --help\" for more information.\n"), progname);
|
|
exit(1);
|
|
}
|
|
|
|
if (datadir_target == NULL)
|
|
{
|
|
pg_log_error("no target data directory specified (--target-pgdata)");
|
|
fprintf(stderr, _("Try \"%s --help\" for more information.\n"), progname);
|
|
exit(1);
|
|
}
|
|
|
|
if (writerecoveryconf && connstr_source == NULL)
|
|
{
|
|
pg_log_error("no source server information (--source--server) specified for --write-recovery-conf");
|
|
fprintf(stderr, _("Try \"%s --help\" for more information.\n"), progname);
|
|
exit(1);
|
|
}
|
|
|
|
if (optind < argc)
|
|
{
|
|
pg_log_error("too many command-line arguments (first is \"%s\")",
|
|
argv[optind]);
|
|
fprintf(stderr, _("Try \"%s --help\" for more information.\n"), progname);
|
|
exit(1);
|
|
}
|
|
|
|
/*
|
|
* Don't allow pg_rewind to be run as root, to avoid overwriting the
|
|
* ownership of files in the data directory. We need only check for root
|
|
* -- any other user won't have sufficient permissions to modify files in
|
|
* the data directory.
|
|
*/
|
|
#ifndef WIN32
|
|
if (geteuid() == 0)
|
|
{
|
|
pg_log_error("cannot be executed by \"root\"");
|
|
fprintf(stderr, _("You must run %s as the PostgreSQL superuser.\n"),
|
|
progname);
|
|
exit(1);
|
|
}
|
|
#endif
|
|
|
|
get_restricted_token();
|
|
|
|
/* Set mask based on PGDATA permissions */
|
|
if (!GetDataDirectoryCreatePerm(datadir_target))
|
|
{
|
|
pg_log_error("could not read permissions of directory \"%s\": %m",
|
|
datadir_target);
|
|
exit(1);
|
|
}
|
|
|
|
umask(pg_mode_mask);
|
|
|
|
atexit(disconnect_atexit);
|
|
|
|
/* Connect to remote server */
|
|
if (connstr_source)
|
|
libpqConnect(connstr_source);
|
|
|
|
/*
|
|
* Ok, we have all the options and we're ready to start. Read in all the
|
|
* information we need from both clusters.
|
|
*/
|
|
buffer = slurpFile(datadir_target, "global/pg_control", &size);
|
|
digestControlFile(&ControlFile_target, buffer, size);
|
|
pg_free(buffer);
|
|
|
|
/*
|
|
* If the target instance was not cleanly shut down, start and stop the
|
|
* target cluster once in single-user mode to enforce recovery to finish,
|
|
* ensuring that the cluster can be used by pg_rewind. Note that if
|
|
* no_ensure_shutdown is specified, pg_rewind ignores this step, and users
|
|
* need to make sure by themselves that the target cluster is in a clean
|
|
* state.
|
|
*/
|
|
if (!no_ensure_shutdown &&
|
|
ControlFile_target.state != DB_SHUTDOWNED &&
|
|
ControlFile_target.state != DB_SHUTDOWNED_IN_RECOVERY)
|
|
{
|
|
ensureCleanShutdown(argv[0]);
|
|
|
|
buffer = slurpFile(datadir_target, "global/pg_control", &size);
|
|
digestControlFile(&ControlFile_target, buffer, size);
|
|
pg_free(buffer);
|
|
}
|
|
|
|
buffer = fetchFile("global/pg_control", &size);
|
|
digestControlFile(&ControlFile_source, buffer, size);
|
|
pg_free(buffer);
|
|
|
|
sanityChecks();
|
|
|
|
/*
|
|
* If both clusters are already on the same timeline, there's nothing to
|
|
* do.
|
|
*/
|
|
if (ControlFile_target.checkPointCopy.ThisTimeLineID == ControlFile_source.checkPointCopy.ThisTimeLineID)
|
|
{
|
|
pg_log_info("source and target cluster are on the same timeline");
|
|
rewind_needed = false;
|
|
}
|
|
else
|
|
{
|
|
findCommonAncestorTimeline(&divergerec, &lastcommontliIndex);
|
|
pg_log_info("servers diverged at WAL location %X/%X on timeline %u",
|
|
(uint32) (divergerec >> 32), (uint32) divergerec,
|
|
targetHistory[lastcommontliIndex].tli);
|
|
|
|
/*
|
|
* Check for the possibility that the target is in fact a direct
|
|
* ancestor of the source. In that case, there is no divergent history
|
|
* in the target that needs rewinding.
|
|
*/
|
|
if (ControlFile_target.checkPoint >= divergerec)
|
|
{
|
|
rewind_needed = true;
|
|
}
|
|
else
|
|
{
|
|
XLogRecPtr chkptendrec;
|
|
|
|
/* Read the checkpoint record on the target to see where it ends. */
|
|
chkptendrec = readOneRecord(datadir_target,
|
|
ControlFile_target.checkPoint,
|
|
targetNentries - 1);
|
|
|
|
/*
|
|
* If the histories diverged exactly at the end of the shutdown
|
|
* checkpoint record on the target, there are no WAL records in
|
|
* the target that don't belong in the source's history, and no
|
|
* rewind is needed.
|
|
*/
|
|
if (chkptendrec == divergerec)
|
|
rewind_needed = false;
|
|
else
|
|
rewind_needed = true;
|
|
}
|
|
}
|
|
|
|
if (!rewind_needed)
|
|
{
|
|
pg_log_info("no rewind required");
|
|
if (writerecoveryconf && !dry_run)
|
|
WriteRecoveryConfig(conn, datadir_target,
|
|
GenerateRecoveryConfig(conn, NULL));
|
|
exit(0);
|
|
}
|
|
|
|
findLastCheckpoint(datadir_target, divergerec,
|
|
lastcommontliIndex,
|
|
&chkptrec, &chkpttli, &chkptredo);
|
|
pg_log_info("rewinding from last common checkpoint at %X/%X on timeline %u",
|
|
(uint32) (chkptrec >> 32), (uint32) chkptrec,
|
|
chkpttli);
|
|
|
|
/*
|
|
* Build the filemap, by comparing the source and target data directories.
|
|
*/
|
|
filemap_create();
|
|
if (showprogress)
|
|
pg_log_info("reading source file list");
|
|
fetchSourceFileList();
|
|
if (showprogress)
|
|
pg_log_info("reading target file list");
|
|
traverse_datadir(datadir_target, &process_target_file);
|
|
|
|
/*
|
|
* Read the target WAL from last checkpoint before the point of fork, to
|
|
* extract all the pages that were modified on the target cluster after
|
|
* the fork. We can stop reading after reaching the final shutdown record.
|
|
* XXX: If we supported rewinding a server that was not shut down cleanly,
|
|
* we would need to replay until the end of WAL here.
|
|
*/
|
|
if (showprogress)
|
|
pg_log_info("reading WAL in target");
|
|
extractPageMap(datadir_target, chkptrec, lastcommontliIndex,
|
|
ControlFile_target.checkPoint);
|
|
filemap_finalize();
|
|
|
|
if (showprogress)
|
|
calculate_totals();
|
|
|
|
/* this is too verbose even for verbose mode */
|
|
if (debug)
|
|
print_filemap();
|
|
|
|
/*
|
|
* Ok, we're ready to start copying things over.
|
|
*/
|
|
if (showprogress)
|
|
{
|
|
pg_log_info("need to copy %lu MB (total source directory size is %lu MB)",
|
|
(unsigned long) (filemap->fetch_size / (1024 * 1024)),
|
|
(unsigned long) (filemap->total_size / (1024 * 1024)));
|
|
|
|
fetch_size = filemap->fetch_size;
|
|
fetch_done = 0;
|
|
}
|
|
|
|
/*
|
|
* This is the point of no return. Once we start copying things, we have
|
|
* modified the target directory and there is no turning back!
|
|
*/
|
|
|
|
executeFileMap();
|
|
|
|
progress_report(true);
|
|
printf("\n");
|
|
|
|
if (showprogress)
|
|
pg_log_info("creating backup label and updating control file");
|
|
createBackupLabel(chkptredo, chkpttli, chkptrec);
|
|
|
|
/*
|
|
* Update control file of target. Make it ready to perform archive
|
|
* recovery when restarting.
|
|
*
|
|
* minRecoveryPoint is set to the current WAL insert location in the
|
|
* source server. Like in an online backup, it's important that we recover
|
|
* all the WAL that was generated while we copied the files over.
|
|
*/
|
|
memcpy(&ControlFile_new, &ControlFile_source, sizeof(ControlFileData));
|
|
|
|
if (connstr_source)
|
|
{
|
|
endrec = libpqGetCurrentXlogInsertLocation();
|
|
endtli = ControlFile_source.checkPointCopy.ThisTimeLineID;
|
|
}
|
|
else
|
|
{
|
|
endrec = ControlFile_source.checkPoint;
|
|
endtli = ControlFile_source.checkPointCopy.ThisTimeLineID;
|
|
}
|
|
ControlFile_new.minRecoveryPoint = endrec;
|
|
ControlFile_new.minRecoveryPointTLI = endtli;
|
|
ControlFile_new.state = DB_IN_ARCHIVE_RECOVERY;
|
|
if (!dry_run)
|
|
update_controlfile(datadir_target, &ControlFile_new, do_sync);
|
|
|
|
if (showprogress)
|
|
pg_log_info("syncing target data directory");
|
|
syncTargetDirectory();
|
|
|
|
if (writerecoveryconf && !dry_run)
|
|
WriteRecoveryConfig(conn, datadir_target,
|
|
GenerateRecoveryConfig(conn, NULL));
|
|
|
|
pg_log_info("Done!");
|
|
|
|
return 0;
|
|
}
|
|
|
|
static void
|
|
sanityChecks(void)
|
|
{
|
|
/* TODO Check that there's no backup_label in either cluster */
|
|
|
|
/* Check system_identifier match */
|
|
if (ControlFile_target.system_identifier != ControlFile_source.system_identifier)
|
|
pg_fatal("source and target clusters are from different systems");
|
|
|
|
/* check version */
|
|
if (ControlFile_target.pg_control_version != PG_CONTROL_VERSION ||
|
|
ControlFile_source.pg_control_version != PG_CONTROL_VERSION ||
|
|
ControlFile_target.catalog_version_no != CATALOG_VERSION_NO ||
|
|
ControlFile_source.catalog_version_no != CATALOG_VERSION_NO)
|
|
{
|
|
pg_fatal("clusters are not compatible with this version of pg_rewind");
|
|
}
|
|
|
|
/*
|
|
* Target cluster need to use checksums or hint bit wal-logging, this to
|
|
* prevent from data corruption that could occur because of hint bits.
|
|
*/
|
|
if (ControlFile_target.data_checksum_version != PG_DATA_CHECKSUM_VERSION &&
|
|
!ControlFile_target.wal_log_hints)
|
|
{
|
|
pg_fatal("target server needs to use either data checksums or \"wal_log_hints = on\"");
|
|
}
|
|
|
|
/*
|
|
* Target cluster better not be running. This doesn't guard against
|
|
* someone starting the cluster concurrently. Also, this is probably more
|
|
* strict than necessary; it's OK if the target node was not shut down
|
|
* cleanly, as long as it isn't running at the moment.
|
|
*/
|
|
if (ControlFile_target.state != DB_SHUTDOWNED &&
|
|
ControlFile_target.state != DB_SHUTDOWNED_IN_RECOVERY)
|
|
pg_fatal("target server must be shut down cleanly");
|
|
|
|
/*
|
|
* When the source is a data directory, also require that the source
|
|
* server is shut down. There isn't any very strong reason for this
|
|
* limitation, but better safe than sorry.
|
|
*/
|
|
if (datadir_source &&
|
|
ControlFile_source.state != DB_SHUTDOWNED &&
|
|
ControlFile_source.state != DB_SHUTDOWNED_IN_RECOVERY)
|
|
pg_fatal("source data directory must be shut down cleanly");
|
|
}
|
|
|
|
/*
|
|
* Print a progress report based on the fetch_size and fetch_done variables.
|
|
*
|
|
* Progress report is written at maximum once per second, unless the
|
|
* force parameter is set to true.
|
|
*/
|
|
void
|
|
progress_report(bool force)
|
|
{
|
|
static pg_time_t last_progress_report = 0;
|
|
int percent;
|
|
char fetch_done_str[32];
|
|
char fetch_size_str[32];
|
|
pg_time_t now;
|
|
|
|
if (!showprogress)
|
|
return;
|
|
|
|
now = time(NULL);
|
|
if (now == last_progress_report && !force)
|
|
return; /* Max once per second */
|
|
|
|
last_progress_report = now;
|
|
percent = fetch_size ? (int) ((fetch_done) * 100 / fetch_size) : 0;
|
|
|
|
/*
|
|
* Avoid overflowing past 100% or the full size. This may make the total
|
|
* size number change as we approach the end of the backup (the estimate
|
|
* will always be wrong if WAL is included), but that's better than having
|
|
* the done column be bigger than the total.
|
|
*/
|
|
if (percent > 100)
|
|
percent = 100;
|
|
if (fetch_done > fetch_size)
|
|
fetch_size = fetch_done;
|
|
|
|
/*
|
|
* Separate step to keep platform-dependent format code out of
|
|
* translatable strings. And we only test for INT64_FORMAT availability
|
|
* in snprintf, not fprintf.
|
|
*/
|
|
snprintf(fetch_done_str, sizeof(fetch_done_str), INT64_FORMAT,
|
|
fetch_done / 1024);
|
|
snprintf(fetch_size_str, sizeof(fetch_size_str), INT64_FORMAT,
|
|
fetch_size / 1024);
|
|
|
|
fprintf(stderr, _("%*s/%s kB (%d%%) copied"),
|
|
(int) strlen(fetch_size_str), fetch_done_str, fetch_size_str,
|
|
percent);
|
|
if (isatty(fileno(stderr)))
|
|
fprintf(stderr, "\r");
|
|
else
|
|
fprintf(stderr, "\n");
|
|
}
|
|
|
|
/*
|
|
* Find minimum from two WAL locations assuming InvalidXLogRecPtr means
|
|
* infinity as src/include/access/timeline.h states. This routine should
|
|
* be used only when comparing WAL locations related to history files.
|
|
*/
|
|
static XLogRecPtr
|
|
MinXLogRecPtr(XLogRecPtr a, XLogRecPtr b)
|
|
{
|
|
if (XLogRecPtrIsInvalid(a))
|
|
return b;
|
|
else if (XLogRecPtrIsInvalid(b))
|
|
return a;
|
|
else
|
|
return Min(a, b);
|
|
}
|
|
|
|
/*
|
|
* Retrieve timeline history for given control file which should behold
|
|
* either source or target.
|
|
*/
|
|
static TimeLineHistoryEntry *
|
|
getTimelineHistory(ControlFileData *controlFile, int *nentries)
|
|
{
|
|
TimeLineHistoryEntry *history;
|
|
TimeLineID tli;
|
|
|
|
tli = controlFile->checkPointCopy.ThisTimeLineID;
|
|
|
|
/*
|
|
* Timeline 1 does not have a history file, so there is no need to check
|
|
* and fake an entry with infinite start and end positions.
|
|
*/
|
|
if (tli == 1)
|
|
{
|
|
history = (TimeLineHistoryEntry *) pg_malloc(sizeof(TimeLineHistoryEntry));
|
|
history->tli = tli;
|
|
history->begin = history->end = InvalidXLogRecPtr;
|
|
*nentries = 1;
|
|
}
|
|
else
|
|
{
|
|
char path[MAXPGPATH];
|
|
char *histfile;
|
|
|
|
TLHistoryFilePath(path, tli);
|
|
|
|
/* Get history file from appropriate source */
|
|
if (controlFile == &ControlFile_source)
|
|
histfile = fetchFile(path, NULL);
|
|
else if (controlFile == &ControlFile_target)
|
|
histfile = slurpFile(datadir_target, path, NULL);
|
|
else
|
|
pg_fatal("invalid control file");
|
|
|
|
history = rewind_parseTimeLineHistory(histfile, tli, nentries);
|
|
pg_free(histfile);
|
|
}
|
|
|
|
if (debug)
|
|
{
|
|
int i;
|
|
|
|
if (controlFile == &ControlFile_source)
|
|
pg_log_debug("Source timeline history:");
|
|
else if (controlFile == &ControlFile_target)
|
|
pg_log_debug("Target timeline history:");
|
|
else
|
|
Assert(false);
|
|
|
|
/*
|
|
* Print the target timeline history.
|
|
*/
|
|
for (i = 0; i < targetNentries; i++)
|
|
{
|
|
TimeLineHistoryEntry *entry;
|
|
|
|
entry = &history[i];
|
|
pg_log_debug("%d: %X/%X - %X/%X", entry->tli,
|
|
(uint32) (entry->begin >> 32), (uint32) (entry->begin),
|
|
(uint32) (entry->end >> 32), (uint32) (entry->end));
|
|
}
|
|
}
|
|
|
|
return history;
|
|
}
|
|
|
|
/*
|
|
* Determine the TLI of the last common timeline in the timeline history of the
|
|
* two clusters. targetHistory is filled with target timeline history and
|
|
* targetNentries is number of items in targetHistory. *tliIndex is set to the
|
|
* index of last common timeline in targetHistory array, and *recptr is set to
|
|
* the position where the timeline history diverged (ie. the first WAL record
|
|
* that's not the same in both clusters).
|
|
*
|
|
* Control files of both clusters must be read into ControlFile_target/source
|
|
* before calling this routine.
|
|
*/
|
|
static void
|
|
findCommonAncestorTimeline(XLogRecPtr *recptr, int *tliIndex)
|
|
{
|
|
TimeLineHistoryEntry *sourceHistory;
|
|
int sourceNentries;
|
|
int i,
|
|
n;
|
|
|
|
/* Retrieve timelines for both source and target */
|
|
sourceHistory = getTimelineHistory(&ControlFile_source, &sourceNentries);
|
|
targetHistory = getTimelineHistory(&ControlFile_target, &targetNentries);
|
|
|
|
/*
|
|
* Trace the history forward, until we hit the timeline diverge. It may
|
|
* still be possible that the source and target nodes used the same
|
|
* timeline number in their history but with different start position
|
|
* depending on the history files that each node has fetched in previous
|
|
* recovery processes. Hence check the start position of the new timeline
|
|
* as well and move down by one extra timeline entry if they do not match.
|
|
*/
|
|
n = Min(sourceNentries, targetNentries);
|
|
for (i = 0; i < n; i++)
|
|
{
|
|
if (sourceHistory[i].tli != targetHistory[i].tli ||
|
|
sourceHistory[i].begin != targetHistory[i].begin)
|
|
break;
|
|
}
|
|
|
|
if (i > 0)
|
|
{
|
|
i--;
|
|
*recptr = MinXLogRecPtr(sourceHistory[i].end, targetHistory[i].end);
|
|
*tliIndex = i;
|
|
|
|
pg_free(sourceHistory);
|
|
return;
|
|
}
|
|
else
|
|
{
|
|
pg_fatal("could not find common ancestor of the source and target cluster's timelines");
|
|
}
|
|
}
|
|
|
|
|
|
/*
|
|
* Create a backup_label file that forces recovery to begin at the last common
|
|
* checkpoint.
|
|
*/
|
|
static void
|
|
createBackupLabel(XLogRecPtr startpoint, TimeLineID starttli, XLogRecPtr checkpointloc)
|
|
{
|
|
XLogSegNo startsegno;
|
|
time_t stamp_time;
|
|
char strfbuf[128];
|
|
char xlogfilename[MAXFNAMELEN];
|
|
struct tm *tmp;
|
|
char buf[1000];
|
|
int len;
|
|
|
|
XLByteToSeg(startpoint, startsegno, WalSegSz);
|
|
XLogFileName(xlogfilename, starttli, startsegno, WalSegSz);
|
|
|
|
/*
|
|
* Construct backup label file
|
|
*/
|
|
stamp_time = time(NULL);
|
|
tmp = localtime(&stamp_time);
|
|
strftime(strfbuf, sizeof(strfbuf), "%Y-%m-%d %H:%M:%S %Z", tmp);
|
|
|
|
len = snprintf(buf, sizeof(buf),
|
|
"START WAL LOCATION: %X/%X (file %s)\n"
|
|
"CHECKPOINT LOCATION: %X/%X\n"
|
|
"BACKUP METHOD: pg_rewind\n"
|
|
"BACKUP FROM: standby\n"
|
|
"START TIME: %s\n",
|
|
/* omit LABEL: line */
|
|
(uint32) (startpoint >> 32), (uint32) startpoint, xlogfilename,
|
|
(uint32) (checkpointloc >> 32), (uint32) checkpointloc,
|
|
strfbuf);
|
|
if (len >= sizeof(buf))
|
|
pg_fatal("backup label buffer too small"); /* shouldn't happen */
|
|
|
|
/* TODO: move old file out of the way, if any. */
|
|
open_target_file("backup_label", true); /* BACKUP_LABEL_FILE */
|
|
write_target_range(buf, 0, len);
|
|
close_target_file();
|
|
}
|
|
|
|
/*
|
|
* Check CRC of control file
|
|
*/
|
|
static void
|
|
checkControlFile(ControlFileData *ControlFile)
|
|
{
|
|
pg_crc32c crc;
|
|
|
|
/* Calculate CRC */
|
|
INIT_CRC32C(crc);
|
|
COMP_CRC32C(crc, (char *) ControlFile, offsetof(ControlFileData, crc));
|
|
FIN_CRC32C(crc);
|
|
|
|
/* And simply compare it */
|
|
if (!EQ_CRC32C(crc, ControlFile->crc))
|
|
pg_fatal("unexpected control file CRC");
|
|
}
|
|
|
|
/*
|
|
* Verify control file contents in the buffer src, and copy it to *ControlFile.
|
|
*/
|
|
static void
|
|
digestControlFile(ControlFileData *ControlFile, char *src, size_t size)
|
|
{
|
|
if (size != PG_CONTROL_FILE_SIZE)
|
|
pg_fatal("unexpected control file size %d, expected %d",
|
|
(int) size, PG_CONTROL_FILE_SIZE);
|
|
|
|
memcpy(ControlFile, src, sizeof(ControlFileData));
|
|
|
|
/* set and validate WalSegSz */
|
|
WalSegSz = ControlFile->xlog_seg_size;
|
|
|
|
if (!IsValidWalSegSize(WalSegSz))
|
|
pg_fatal(ngettext("WAL segment size must be a power of two between 1 MB and 1 GB, but the control file specifies %d byte",
|
|
"WAL segment size must be a power of two between 1 MB and 1 GB, but the control file specifies %d bytes",
|
|
WalSegSz),
|
|
WalSegSz);
|
|
|
|
/* Additional checks on control file */
|
|
checkControlFile(ControlFile);
|
|
}
|
|
|
|
/*
|
|
* Sync target data directory to ensure that modifications are safely on disk.
|
|
*
|
|
* We do this once, for the whole data directory, for performance reasons. At
|
|
* the end of pg_rewind's run, the kernel is likely to already have flushed
|
|
* most dirty buffers to disk. Additionally fsync_pgdata uses a two-pass
|
|
* approach (only initiating writeback in the first pass), which often reduces
|
|
* the overall amount of IO noticeably.
|
|
*/
|
|
static void
|
|
syncTargetDirectory(void)
|
|
{
|
|
if (!do_sync || dry_run)
|
|
return;
|
|
|
|
fsync_pgdata(datadir_target, PG_VERSION_NUM);
|
|
}
|
|
|
|
/*
|
|
* Ensure clean shutdown of target instance by launching single-user mode
|
|
* postgres to do crash recovery.
|
|
*/
|
|
static void
|
|
ensureCleanShutdown(const char *argv0)
|
|
{
|
|
int ret;
|
|
#define MAXCMDLEN (2 * MAXPGPATH)
|
|
char exec_path[MAXPGPATH];
|
|
char cmd[MAXCMDLEN];
|
|
|
|
/* locate postgres binary */
|
|
if ((ret = find_other_exec(argv0, "postgres",
|
|
PG_BACKEND_VERSIONSTR,
|
|
exec_path)) < 0)
|
|
{
|
|
char full_path[MAXPGPATH];
|
|
|
|
if (find_my_exec(argv0, full_path) < 0)
|
|
strlcpy(full_path, progname, sizeof(full_path));
|
|
|
|
if (ret == -1)
|
|
pg_fatal("The program \"%s\" is needed by %s but was\n"
|
|
"not found in the same directory as \"%s\".\n"
|
|
"Check your installation.",
|
|
"postgres", progname, full_path);
|
|
else
|
|
pg_fatal("The program \"%s\" was found by \"%s\" but was\n"
|
|
"not the same version as %s.\n"
|
|
"Check your installation.",
|
|
"postgres", full_path, progname);
|
|
}
|
|
|
|
pg_log_info("executing \"%s\" for target server to complete crash recovery",
|
|
exec_path);
|
|
|
|
/*
|
|
* Skip processing if requested, but only after ensuring presence of
|
|
* postgres.
|
|
*/
|
|
if (dry_run)
|
|
return;
|
|
|
|
/*
|
|
* Finally run postgres in single-user mode. There is no need to use
|
|
* fsync here. This makes the recovery faster, and the target data folder
|
|
* is synced at the end anyway.
|
|
*/
|
|
snprintf(cmd, MAXCMDLEN, "\"%s\" --single -F -D \"%s\" template1 < \"%s\"",
|
|
exec_path, datadir_target, DEVNULL);
|
|
|
|
if (system(cmd) != 0)
|
|
{
|
|
pg_log_error("postgres single-user mode of target instance failed");
|
|
pg_fatal("Command was: %s", cmd);
|
|
}
|
|
}
|
|
|
|
static void
|
|
disconnect_atexit(void)
|
|
{
|
|
if (conn != NULL)
|
|
PQfinish(conn);
|
|
}
|