* PostgreSQL transaction log manager
*
*
- * Portions Copyright (c) 1996-2008, PostgreSQL Global Development Group
+ * Portions Copyright (c) 1996-2009, PostgreSQL Global Development Group
* Portions Copyright (c) 1994, Regents of the University of California
*
- * $PostgreSQL: pgsql/src/backend/access/transam/xlog.c,v 1.325 2008/12/24 20:41:29 momjian Exp $
+ * $PostgreSQL: pgsql/src/backend/access/transam/xlog.c,v 1.338 2009/05/14 20:31:09 heikki Exp $
*
*-------------------------------------------------------------------------
*/
#include <ctype.h>
#include <signal.h>
#include <time.h>
+#include <fcntl.h>
#include <sys/stat.h>
#include <sys/time.h>
#include <sys/wait.h>
#include "catalog/pg_control.h"
#include "catalog/pg_type.h"
#include "funcapi.h"
+#include "libpq/pqsignal.h"
#include "miscadmin.h"
#include "pgstat.h"
#include "postmaster/bgwriter.h"
#include "storage/smgr.h"
#include "storage/spin.h"
#include "utils/builtins.h"
+#include "utils/flatfiles.h"
#include "utils/guc.h"
#include "utils/ps_status.h"
#include "pg_trace.h"
*/
TimeLineID ThisTimeLineID = 0;
-/* Are we doing recovery from XLOG? */
+/*
+ * Are we doing recovery from XLOG?
+ *
+ * This is only ever true in the startup process, even if the system is still
+ * in recovery. Prior to 8.4, all activity during recovery were carried out
+ * by Startup process. This local variable continues to be used in functions
+ * that need to act differently when called from a redo function (e.g skip
+ * WAL logging). To check whether the system is in recovery regardless of what
+ * process you're running in, use RecoveryInProgress().
+ */
bool InRecovery = false;
/* Are we recovering using offline XLOG archives? */
static bool InArchiveRecovery = false;
+/*
+ * Local copy of SharedRecoveryInProgress variable. True actually means "not
+ * known, need to check the shared state"
+ */
+static bool LocalRecoveryInProgress = true;
+
/* Was the last xlog file restored from archive, or local? */
static bool restoredFromArchive = false;
/* options taken from recovery.conf */
static char *recoveryRestoreCommand = NULL;
+static char *recoveryEndCommand = NULL;
static bool recoveryTarget = false;
static bool recoveryTargetExact = false;
static bool recoveryTargetInclusive = true;
-static bool recoveryLogRestartpoints = false;
static TransactionId recoveryTargetXid;
static TimestampTz recoveryTargetTime;
static TimestampTz recoveryLastXTime = 0;
* ControlFileLock: must be held to read/update control file or create
* new log file.
*
- * CheckpointLock: must be held to do a checkpoint (ensures only one
- * checkpointer at a time; currently, with all checkpoints done by the
- * bgwriter, this is just pro forma).
+ * CheckpointLock: must be held to do a checkpoint or restartpoint (ensures
+ * only one checkpointer at a time)
*
*----------
*/
int XLogCacheBlck; /* highest allocated xlog buffer index */
TimeLineID ThisTimeLineID;
+ /*
+ * SharedRecoveryInProgress indicates if we're still in crash or archive
+ * recovery. It's checked by RecoveryInProgress().
+ */
+ bool SharedRecoveryInProgress;
+
+ /*
+ * During recovery, we keep a copy of the latest checkpoint record
+ * here. Used by the background writer when it wants to create
+ * a restartpoint.
+ *
+ * Protected by info_lck.
+ */
+ XLogRecPtr lastCheckPointRecPtr;
+ CheckPoint lastCheckPoint;
+
+ /* end+1 of the last record replayed (or being replayed) */
+ XLogRecPtr replayEndRecPtr;
+
slock_t info_lck; /* locks shared variables shown above */
} XLogCtlData;
static XLogRecPtr EndRecPtr; /* end+1 of last record read */
static XLogRecord *nextRecord = NULL;
static TimeLineID lastPageTLI = 0;
+static XLogRecPtr minRecoveryPoint; /* local copy of ControlFile->minRecoveryPoint */
+static bool updateMinRecoveryPoint = true;
static bool InRedo = false;
+/*
+ * Flag set by interrupt handlers for later service in the redo loop.
+ */
+static volatile sig_atomic_t got_SIGHUP = false;
+static volatile sig_atomic_t shutdown_requested = false;
+/*
+ * Flag set when executing a restore command, to tell SIGTERM signal handler
+ * that it's safe to just proc_exit.
+ */
+static volatile sig_atomic_t in_restore_command = false;
+
static void XLogArchiveNotify(const char *xlog);
static void XLogArchiveNotifySeg(uint32 log, uint32 seg);
static void XLogFileClose(void);
static bool RestoreArchivedFile(char *path, const char *xlogfname,
const char *recovername, off_t expectedSize);
+static void ExecuteRecoveryEndCommand(void);
static void PreallocXlogFiles(XLogRecPtr endptr);
static void RemoveOldXlogFiles(uint32 log, uint32 seg, XLogRecPtr endptr);
static void ValidateXLOGDirectoryStructure(void);
static void CleanupBackupHistory(void);
+static void UpdateMinRecoveryPoint(XLogRecPtr lsn, bool force);
static XLogRecord *ReadRecord(XLogRecPtr *RecPtr, int emode);
static bool ValidXLOGHeader(XLogPageHeader hdr, int emode);
static XLogRecord *ReadCheckpointRecord(XLogRecPtr RecPtr, int whichChkpt);
bool doPageWrites;
bool isLogSwitch = (rmid == RM_XLOG_ID && info == XLOG_SWITCH);
+ /* cross-check on whether we should be here or not */
+ if (RecoveryInProgress())
+ elog(FATAL, "cannot make new WAL entries during recovery");
+
/* info's high bits are reserved for use by me */
if (info & XLR_INFO_MASK)
elog(PANIC, "invalid xlog info mask %02X", info);
}
/*
+ * Advance minRecoveryPoint in control file.
+ *
+ * If we crash during recovery, we must reach this point again before the
+ * database is consistent.
+ *
+ * If 'force' is true, 'lsn' argument is ignored. Otherwise, minRecoveryPoint
+ * is is only updated if it's not already greater than or equal to 'lsn'.
+ */
+static void
+UpdateMinRecoveryPoint(XLogRecPtr lsn, bool force)
+{
+ /* Quick check using our local copy of the variable */
+ if (!updateMinRecoveryPoint || (!force && XLByteLE(lsn, minRecoveryPoint)))
+ return;
+
+ LWLockAcquire(ControlFileLock, LW_EXCLUSIVE);
+
+ /* update local copy */
+ minRecoveryPoint = ControlFile->minRecoveryPoint;
+
+ /*
+ * An invalid minRecoveryPoint means that we need to recover all the WAL,
+ * ie. crash recovery. Don't update the control file in that case.
+ */
+ if (minRecoveryPoint.xlogid == 0 && minRecoveryPoint.xrecoff == 0)
+ updateMinRecoveryPoint = false;
+ else if (force || XLByteLT(minRecoveryPoint, lsn))
+ {
+ /* use volatile pointer to prevent code rearrangement */
+ volatile XLogCtlData *xlogctl = XLogCtl;
+ XLogRecPtr newMinRecoveryPoint;
+
+ /*
+ * To avoid having to update the control file too often, we update it
+ * all the way to the last record being replayed, even though 'lsn'
+ * would suffice for correctness.
+ */
+ SpinLockAcquire(&xlogctl->info_lck);
+ newMinRecoveryPoint = xlogctl->replayEndRecPtr;
+ SpinLockRelease(&xlogctl->info_lck);
+
+ /* update control file */
+ if (XLByteLT(ControlFile->minRecoveryPoint, newMinRecoveryPoint))
+ {
+ ControlFile->minRecoveryPoint = newMinRecoveryPoint;
+ UpdateControlFile();
+ minRecoveryPoint = newMinRecoveryPoint;
+
+ ereport(DEBUG2,
+ (errmsg("updated min recovery point to %X/%X",
+ minRecoveryPoint.xlogid, minRecoveryPoint.xrecoff)));
+ }
+ }
+ LWLockRelease(ControlFileLock);
+}
+
+/*
* Ensure that all XLOG data through the given position is flushed to disk.
*
* NOTE: this differs from XLogWrite mainly in that the WALWriteLock is not
XLogRecPtr WriteRqstPtr;
XLogwrtRqst WriteRqst;
- /* Disabled during REDO */
- if (InRedo)
+ /*
+ * During REDO, we don't try to flush the WAL, but update minRecoveryPoint
+ * instead.
+ */
+ if (RecoveryInProgress())
+ {
+ UpdateMinRecoveryPoint(record, false);
return;
+ }
/* Quick exit if already known flushed */
if (XLByteLE(record, LogwrtResult.Flush))
* the bad page is encountered again during recovery then we would be
* unable to restart the database at all! (This scenario has actually
* happened in the field several times with 7.1 releases. Note that we
- * cannot get here while InRedo is true, but if the bad page is brought in
- * and marked dirty during recovery then CreateCheckPoint will try to
- * flush it at the end of recovery.)
+ * cannot get here while RecoveryInProgress(), but if the bad page is
+ * brought in and marked dirty during recovery then if a checkpoint were
+ * performed at the end of recovery it will try to flush it.
*
* The current approach is to ERROR under normal conditions, but only
* WARNING during recovery, so that the system can be brought up even if
XLogRecPtr WriteRqstPtr;
bool flexible = true;
+ /* XLOG doesn't need flushing during recovery */
+ if (RecoveryInProgress())
+ return;
+
/* read LogwrtResult and update local state */
{
/* use volatile pointer to prevent code rearrangement */
/* use volatile pointer to prevent code rearrangement */
volatile XLogCtlData *xlogctl = XLogCtl;
+ /* There's no asynchronously committed transactions during recovery */
+ if (RecoveryInProgress())
+ return;
+
SpinLockAcquire(&xlogctl->info_lck);
WriteRqstPtr = xlogctl->asyncCommitLSN;
SpinLockRelease(&xlogctl->info_lck);
bool
XLogNeedsFlush(XLogRecPtr record)
{
+ /* XLOG doesn't need flushing during recovery */
+ if (RecoveryInProgress())
+ return false;
+
/* Quick exit if already known flushed */
if (XLByteLE(record, LogwrtResult.Flush))
return false;
Assert(openLogFile >= 0);
/*
- * posix_fadvise is problematic on many platforms: on older x86 Linux it
- * just dumps core, and there are reports of problems on PPC platforms as
- * well. The following is therefore disabled for the time being. We could
- * consider some kind of configure test to see if it's safe to use, but
- * since we lack hard evidence that there's any useful performance gain to
- * be had, spending time on that seems unprofitable for now.
- */
-#ifdef NOT_USED
-
- /*
* WAL segment files will not be re-read in normal operation, so we advise
- * OS to release any cached pages. But do not do so if WAL archiving is
- * active, because archiver process could use the cache to read the WAL
- * segment.
- *
- * While O_DIRECT works for O_SYNC, posix_fadvise() works for fsync() and
- * O_SYNC, and some platforms only have posix_fadvise().
- */
-#if defined(HAVE_DECL_POSIX_FADVISE) && defined(POSIX_FADV_DONTNEED)
- if (!XLogArchivingActive())
- posix_fadvise(openLogFile, 0, 0, POSIX_FADV_DONTNEED);
+ * the OS to release any cached pages. But do not do so if WAL archiving
+ * is active, because archiver process could use the cache to read the WAL
+ * segment. Also, don't bother with it if we are using O_DIRECT, since
+ * the kernel is presumably not caching in that case.
+ */
+#if defined(USE_POSIX_FADVISE) && defined(POSIX_FADV_DONTNEED)
+ if (!XLogArchivingActive() &&
+ (get_sync_bit(sync_method) & PG_O_DIRECT) == 0)
+ (void) posix_fadvise(openLogFile, 0, 0, POSIX_FADV_DONTNEED);
#endif
-#endif /* NOT_USED */
if (close(openLogFile))
ereport(PANIC,
xlogRestoreCmd)));
/*
+ * Set in_restore_command to tell the signal handler that we should exit
+ * right away on SIGTERM. We know that we're in a safe point to do that.
+ * Check if we had already received the signal, so that we don't miss a
+ * shutdown request received just before this.
+ */
+ in_restore_command = true;
+ if (shutdown_requested)
+ proc_exit(1);
+
+ /*
* Copy xlog from archival storage to XLOGDIR
*/
rc = system(xlogRestoreCmd);
+
+ in_restore_command = false;
+
if (rc == 0)
{
/*
* assume that recovery is complete and start up the database!) It's
* essential to abort on child SIGINT and SIGQUIT, because per spec
* system() ignores SIGINT and SIGQUIT while waiting; if we see one of
- * those it's a good bet we should have gotten it too. Aborting on other
- * signals such as SIGTERM seems a good idea as well.
+ * those it's a good bet we should have gotten it too.
+ *
+ * On SIGTERM, assume we have received a fast shutdown request, and exit
+ * cleanly. It's pure chance whether we receive the SIGTERM first, or the
+ * child process. If we receive it first, the signal handler will call
+ * proc_exit, otherwise we do it here. If we or the child process
+ * received SIGTERM for any other reason than a fast shutdown request,
+ * postmaster will perform an immediate shutdown when it sees us exiting
+ * unexpectedly.
*
* Per the Single Unix Spec, shells report exit status > 128 when a called
* command died on a signal. Also, 126 and 127 are used to report
* problems such as an unfindable command; treat those as fatal errors
* too.
*/
+ if (WTERMSIG(rc) == SIGTERM)
+ proc_exit(1);
+
signaled = WIFSIGNALED(rc) || WEXITSTATUS(rc) > 125;
ereport(signaled ? FATAL : DEBUG2,
}
/*
+ * Attempt to execute the recovery_end_command.
+ */
+static void
+ExecuteRecoveryEndCommand(void)
+{
+ char xlogRecoveryEndCmd[MAXPGPATH];
+ char lastRestartPointFname[MAXPGPATH];
+ char *dp;
+ char *endp;
+ const char *sp;
+ int rc;
+ bool signaled;
+ uint32 restartLog;
+ uint32 restartSeg;
+
+ Assert(recoveryEndCommand);
+
+ /*
+ * Calculate the archive file cutoff point for use during log shipping
+ * replication. All files earlier than this point can be deleted
+ * from the archive, though there is no requirement to do so.
+ *
+ * We initialise this with the filename of an InvalidXLogRecPtr, which
+ * will prevent the deletion of any WAL files from the archive
+ * because of the alphabetic sorting property of WAL filenames.
+ *
+ * Once we have successfully located the redo pointer of the checkpoint
+ * from which we start recovery we never request a file prior to the redo
+ * pointer of the last restartpoint. When redo begins we know that we
+ * have successfully located it, so there is no need for additional
+ * status flags to signify the point when we can begin deleting WAL files
+ * from the archive.
+ */
+ if (InRedo)
+ {
+ XLByteToSeg(ControlFile->checkPointCopy.redo,
+ restartLog, restartSeg);
+ XLogFileName(lastRestartPointFname,
+ ControlFile->checkPointCopy.ThisTimeLineID,
+ restartLog, restartSeg);
+ }
+ else
+ XLogFileName(lastRestartPointFname, 0, 0, 0);
+
+ /*
+ * construct the command to be executed
+ */
+ dp = xlogRecoveryEndCmd;
+ endp = xlogRecoveryEndCmd + MAXPGPATH - 1;
+ *endp = '\0';
+
+ for (sp = recoveryEndCommand; *sp; sp++)
+ {
+ if (*sp == '%')
+ {
+ switch (sp[1])
+ {
+ case 'r':
+ /* %r: filename of last restartpoint */
+ sp++;
+ StrNCpy(dp, lastRestartPointFname, endp - dp);
+ dp += strlen(dp);
+ break;
+ case '%':
+ /* convert %% to a single % */
+ sp++;
+ if (dp < endp)
+ *dp++ = *sp;
+ break;
+ default:
+ /* otherwise treat the % as not special */
+ if (dp < endp)
+ *dp++ = *sp;
+ break;
+ }
+ }
+ else
+ {
+ if (dp < endp)
+ *dp++ = *sp;
+ }
+ }
+ *dp = '\0';
+
+ ereport(DEBUG3,
+ (errmsg_internal("executing recovery end command \"%s\"",
+ xlogRecoveryEndCmd)));
+
+ /*
+ * Copy xlog from archival storage to XLOGDIR
+ */
+ rc = system(xlogRecoveryEndCmd);
+ if (rc != 0)
+ {
+ /*
+ * If the failure was due to any sort of signal, it's best to punt and
+ * abort recovery. See also detailed comments on signals in
+ * RestoreArchivedFile().
+ */
+ signaled = WIFSIGNALED(rc) || WEXITSTATUS(rc) > 125;
+
+ ereport(signaled ? FATAL : WARNING,
+ (errmsg("recovery_end_command \"%s\": return code %d",
+ xlogRecoveryEndCmd, rc)));
+ }
+}
+
+/*
* Preallocate log files beyond the specified log endpoint.
*
* XXX this is currently extremely conservative, since it forces only one
* page might not be. This will force us to replay all subsequent
* modifications of the page that appear in XLOG, rather than possibly
* ignoring them as already applied, but that's not a huge drawback.
+ *
+ * If 'cleanup' is true, a cleanup lock is used when restoring blocks.
+ * Otherwise, a normal exclusive lock is used. At the moment, that's just
+ * pro forma, because there can't be any regular backends in the system
+ * during recovery. The 'cleanup' argument applies to all backup blocks
+ * in the WAL record, that suffices for now.
*/
-static void
-RestoreBkpBlocks(XLogRecord *record, XLogRecPtr lsn)
+void
+RestoreBkpBlocks(XLogRecPtr lsn, XLogRecord *record, bool cleanup)
{
Buffer buffer;
Page page;
char *blk;
int i;
+ if (!(record->xl_info & XLR_BKP_BLOCK_MASK))
+ return;
+
blk = (char *) XLogRecGetData(record) + record->xl_len;
for (i = 0; i < XLR_MAX_BKP_BLOCKS; i++)
{
buffer = XLogReadBufferExtended(bkpb.node, bkpb.fork, bkpb.block,
RBM_ZERO);
Assert(BufferIsValid(buffer));
+ if (cleanup)
+ LockBufferForCleanup(buffer);
+ else
+ LockBuffer(buffer, BUFFER_LOCK_EXCLUSIVE);
+
page = (Page) BufferGetPage(buffer);
if (bkpb.hole_length == 0)
(errmsg("incorrect checksum in control file")));
/*
- * Do compatibility checking immediately. We do this here for 2 reasons:
- *
- * (1) if the database isn't compatible with the backend executable, we
- * want to abort before we can possibly do any damage;
- *
- * (2) this code is executed in the postmaster, so the setlocale() will
- * propagate to forked backends, which aren't going to read this file for
- * themselves. (These locale settings are considered critical
- * compatibility items because they can affect sort order of indexes.)
+ * Do compatibility checking immediately. If the database isn't
+ * compatible with the backend executable, we want to abort before we
+ * can possibly do any damage.
*/
if (ControlFile->catalog_version_no != CATALOG_VERSION_NO)
ereport(FATAL,
(errmsg("restore_command = '%s'",
recoveryRestoreCommand)));
}
+ else if (strcmp(tok1, "recovery_end_command") == 0)
+ {
+ recoveryEndCommand = pstrdup(tok2);
+ ereport(LOG,
+ (errmsg("recovery_end_command = '%s'",
+ recoveryEndCommand)));
+ }
else if (strcmp(tok1, "recovery_target_timeline") == 0)
{
rtliGiven = true;
ereport(LOG,
(errmsg("recovery_target_inclusive = %s", tok2)));
}
- else if (strcmp(tok1, "log_restartpoints") == 0)
- {
- /*
- * does nothing if a recovery_target is not also set
- */
- if (!parse_bool(tok2, &recoveryLogRestartpoints))
- ereport(ERROR,
- (errcode(ERRCODE_INVALID_PARAMETER_VALUE),
- errmsg("parameter \"log_restartpoints\" requires a Boolean value")));
- ereport(LOG,
- (errmsg("log_restartpoints = %s", tok2)));
- }
else
ereport(FATAL,
(errmsg("unrecognized recovery parameter \"%s\"",
* If we are establishing a new timeline, we have to copy data from
* the last WAL segment of the old timeline to create a starting WAL
* segment for the new timeline.
+ *
+ * Notify the archiver that the last WAL segment of the old timeline
+ * is ready to copy to archival storage. Otherwise, it is not archived
+ * for a while.
*/
if (endTLI != ThisTimeLineID)
+ {
XLogFileCopy(endLogId, endLogSeg,
endTLI, endLogId, endLogSeg);
+
+ if (XLogArchivingActive())
+ {
+ XLogFileName(xlogpath, endTLI, endLogId, endLogSeg);
+ XLogArchiveNotify(xlogpath);
+ }
+ }
}
/*
XLogRecPtr RecPtr,
LastRec,
checkPointLoc,
- minRecoveryLoc,
+ backupStopLoc,
EndOfLog;
uint32 endLogId;
uint32 endLogSeg;
uint32 freespace;
TransactionId oldestActiveXID;
+ XLogCtl->SharedRecoveryInProgress = true;
+
/*
* Read control file and check XLOG status looks valid.
*
recoveryTargetTLI,
ControlFile->checkPointCopy.ThisTimeLineID)));
- if (read_backup_label(&checkPointLoc, &minRecoveryLoc))
+ if (read_backup_label(&checkPointLoc, &backupStopLoc))
{
/*
* When a backup_label file is present, we want to roll forward from
ControlFile->prevCheckPoint = ControlFile->checkPoint;
ControlFile->checkPoint = checkPointLoc;
ControlFile->checkPointCopy = checkPoint;
- if (minRecoveryLoc.xlogid != 0 || minRecoveryLoc.xrecoff != 0)
- ControlFile->minRecoveryPoint = minRecoveryLoc;
+ if (backupStopLoc.xlogid != 0 || backupStopLoc.xrecoff != 0)
+ {
+ if (XLByteLT(ControlFile->minRecoveryPoint, backupStopLoc))
+ ControlFile->minRecoveryPoint = backupStopLoc;
+ }
ControlFile->time = (pg_time_t) time(NULL);
+ /* No need to hold ControlFileLock yet, we aren't up far enough */
UpdateControlFile();
+ /* update our local copy of minRecoveryPoint */
+ minRecoveryPoint = ControlFile->minRecoveryPoint;
+
+ /*
+ * Reset pgstat data, because it may be invalid after recovery.
+ */
+ pgstat_reset_all();
+
/*
* If there was a backup label file, it's done its job and the info
* has now been propagated into pg_control. We must get rid of the
{
bool recoveryContinue = true;
bool recoveryApply = true;
+ bool reachedMinRecoveryPoint = false;
ErrorContextCallback errcontext;
+ /* use volatile pointer to prevent code rearrangement */
+ volatile XLogCtlData *xlogctl = XLogCtl;
+
+ /* Update shared replayEndRecPtr */
+ SpinLockAcquire(&xlogctl->info_lck);
+ xlogctl->replayEndRecPtr = ReadRecPtr;
+ SpinLockRelease(&xlogctl->info_lck);
InRedo = true;
- ereport(LOG,
- (errmsg("redo starts at %X/%X",
- ReadRecPtr.xlogid, ReadRecPtr.xrecoff)));
+
+ if (minRecoveryPoint.xlogid == 0 && minRecoveryPoint.xrecoff == 0)
+ ereport(LOG,
+ (errmsg("redo starts at %X/%X",
+ ReadRecPtr.xlogid, ReadRecPtr.xrecoff)));
+ else
+ ereport(LOG,
+ (errmsg("redo starts at %X/%X, consistency will be reached at %X/%X",
+ ReadRecPtr.xlogid, ReadRecPtr.xrecoff,
+ minRecoveryPoint.xlogid, minRecoveryPoint.xrecoff)));
+
+ /*
+ * Let postmaster know we've started redo now, so that it can
+ * launch bgwriter to perform restartpoints. We don't bother
+ * during crash recovery as restartpoints can only be performed
+ * during archive recovery. And we'd like to keep crash recovery
+ * simple, to avoid introducing bugs that could you from
+ * recovering after crash.
+ *
+ * After this point, we can no longer assume that we're the only
+ * process in addition to postmaster!
+ */
+ if (InArchiveRecovery && IsUnderPostmaster)
+ SendPostmasterSignal(PMSIGNAL_RECOVERY_STARTED);
/*
* main redo apply loop
#endif
/*
+ * Check if we were requested to re-read config file.
+ */
+ if (got_SIGHUP)
+ {
+ got_SIGHUP = false;
+ ProcessConfigFile(PGC_SIGHUP);
+ }
+
+ /*
+ * Check if we were requested to exit without finishing
+ * recovery.
+ */
+ if (shutdown_requested)
+ proc_exit(1);
+
+ /*
+ * Have we reached our safe starting point? If so, we can
+ * tell postmaster that the database is consistent now.
+ */
+ if (!reachedMinRecoveryPoint &&
+ XLByteLE(minRecoveryPoint, EndRecPtr))
+ {
+ reachedMinRecoveryPoint = true;
+ if (InArchiveRecovery)
+ {
+ ereport(LOG,
+ (errmsg("consistent recovery state reached")));
+ if (IsUnderPostmaster)
+ SendPostmasterSignal(PMSIGNAL_RECOVERY_CONSISTENT);
+ }
+ }
+
+ /*
* Have we reached our recovery target?
*/
if (recoveryStopsHere(record, &recoveryApply))
TransactionIdAdvance(ShmemVariableCache->nextXid);
}
- if (record->xl_info & XLR_BKP_BLOCK_MASK)
- RestoreBkpBlocks(record, EndRecPtr);
+ /*
+ * Update shared replayEndRecPtr before replaying this
+ * record, so that XLogFlush will update minRecoveryPoint
+ * correctly.
+ */
+ SpinLockAcquire(&xlogctl->info_lck);
+ xlogctl->replayEndRecPtr = EndRecPtr;
+ SpinLockRelease(&xlogctl->info_lck);
RmgrTable[record->xl_rmid].rm_redo(EndRecPtr, record);
* Complain if we did not roll forward far enough to render the backup
* dump consistent.
*/
- if (XLByteLT(EndOfLog, ControlFile->minRecoveryPoint))
+ if (InRecovery && XLByteLT(EndOfLog, minRecoveryPoint))
{
if (reachedStopPoint) /* stopped because of stop request */
ereport(FATAL,
- (errmsg("requested recovery stop point is before end time of backup dump")));
+ (errmsg("requested recovery stop point is before consistent recovery point")));
else /* ran off end of WAL */
ereport(FATAL,
- (errmsg("WAL ends before end time of backup dump")));
+ (errmsg("WAL ends before consistent recovery point")));
}
/*
/* Pre-scan prepared transactions to find out the range of XIDs present */
oldestActiveXID = PrescanPreparedTransactions();
+ /*
+ * Allow writing WAL for us, so that we can create a checkpoint record.
+ * But not yet for other backends!
+ */
+ LocalRecoveryInProgress = false;
+
if (InRecovery)
{
int rmid;
XLogCheckInvalidPages();
/*
- * Reset pgstat data, because it may be invalid after recovery.
- */
- pgstat_reset_all();
-
- /*
* Perform a checkpoint to update all our recovery activity to disk.
*
* Note that we write a shutdown checkpoint rather than an on-line
* allows some extra error checking in xlog_redo.
*/
CreateCheckPoint(CHECKPOINT_IS_SHUTDOWN | CHECKPOINT_IMMEDIATE);
+
+ if (recoveryEndCommand)
+ ExecuteRecoveryEndCommand();
}
/*
*/
InRecovery = false;
+ LWLockAcquire(ControlFileLock, LW_EXCLUSIVE);
ControlFile->state = DB_IN_PRODUCTION;
ControlFile->time = (pg_time_t) time(NULL);
UpdateControlFile();
+ LWLockRelease(ControlFileLock);
/* start the archive_timeout timer running */
- XLogCtl->Write.lastSegSwitchTime = ControlFile->time;
+ XLogCtl->Write.lastSegSwitchTime = (pg_time_t) time(NULL);
/* initialize shared-memory copy of latest checkpoint XID/epoch */
XLogCtl->ckptXidEpoch = ControlFile->checkPointCopy.nextXidEpoch;
readRecordBuf = NULL;
readRecordBufSize = 0;
}
+
+ /*
+ * All done. Allow others to write WAL.
+ */
+ XLogCtl->SharedRecoveryInProgress = false;
+}
+
+/*
+ * Is the system still in recovery?
+ *
+ * As a side-effect, we initialize the local TimeLineID and RedoRecPtr
+ * variables the first time we see that recovery is finished.
+ */
+bool
+RecoveryInProgress(void)
+{
+ /*
+ * We check shared state each time only until we leave recovery mode.
+ * We can't re-enter recovery, so we rely on the local state variable
+ * after that.
+ */
+ if (!LocalRecoveryInProgress)
+ return false;
+ else
+ {
+ /* use volatile pointer to prevent code rearrangement */
+ volatile XLogCtlData *xlogctl = XLogCtl;
+
+ LocalRecoveryInProgress = xlogctl->SharedRecoveryInProgress;
+
+ /*
+ * Initialize TimeLineID and RedoRecPtr the first time we see that
+ * recovery is finished.
+ */
+ if (!LocalRecoveryInProgress)
+ InitXLOGAccess();
+
+ return LocalRecoveryInProgress;
+ }
}
/*
{
/* ThisTimeLineID doesn't change so we need no lock to copy it */
ThisTimeLineID = XLogCtl->ThisTimeLineID;
+ Assert(ThisTimeLineID != 0);
+
/* Use GetRedoRecPtr to copy the RedoRecPtr safely */
(void) GetRedoRecPtr();
}
ereport(LOG,
(errmsg("shutting down")));
- CreateCheckPoint(CHECKPOINT_IS_SHUTDOWN | CHECKPOINT_IMMEDIATE);
+ if (RecoveryInProgress())
+ CreateRestartPoint(CHECKPOINT_IS_SHUTDOWN | CHECKPOINT_IMMEDIATE);
+ else
+ CreateCheckPoint(CHECKPOINT_IS_SHUTDOWN | CHECKPOINT_IMMEDIATE);
ShutdownCLOG();
ShutdownSUBTRANS();
ShutdownMultiXact();
* Log start of a checkpoint.
*/
static void
-LogCheckpointStart(int flags)
+LogCheckpointStart(int flags, bool restartpoint)
{
- elog(LOG, "checkpoint starting:%s%s%s%s%s%s",
+ char *msg;
+
+ /*
+ * XXX: This is hopelessly untranslatable. We could call gettext_noop
+ * for the main message, but what about all the flags?
+ */
+ if (restartpoint)
+ msg = "restartpoint starting:%s%s%s%s%s%s";
+ else
+ msg = "checkpoint starting:%s%s%s%s%s%s";
+
+ elog(LOG, msg,
(flags & CHECKPOINT_IS_SHUTDOWN) ? " shutdown" : "",
(flags & CHECKPOINT_IMMEDIATE) ? " immediate" : "",
(flags & CHECKPOINT_FORCE) ? " force" : "",
* Log end of a checkpoint.
*/
static void
-LogCheckpointEnd(void)
+LogCheckpointEnd(bool restartpoint)
{
long write_secs,
sync_secs,
CheckpointStats.ckpt_sync_end_t,
&sync_secs, &sync_usecs);
- elog(LOG, "checkpoint complete: wrote %d buffers (%.1f%%); "
- "%d transaction log file(s) added, %d removed, %d recycled; "
- "write=%ld.%03d s, sync=%ld.%03d s, total=%ld.%03d s",
- CheckpointStats.ckpt_bufs_written,
- (double) CheckpointStats.ckpt_bufs_written * 100 / NBuffers,
- CheckpointStats.ckpt_segs_added,
- CheckpointStats.ckpt_segs_removed,
- CheckpointStats.ckpt_segs_recycled,
- write_secs, write_usecs / 1000,
- sync_secs, sync_usecs / 1000,
- total_secs, total_usecs / 1000);
+ if (restartpoint)
+ elog(LOG, "restartpoint complete: wrote %d buffers (%.1f%%); "
+ "write=%ld.%03d s, sync=%ld.%03d s, total=%ld.%03d s",
+ CheckpointStats.ckpt_bufs_written,
+ (double) CheckpointStats.ckpt_bufs_written * 100 / NBuffers,
+ write_secs, write_usecs / 1000,
+ sync_secs, sync_usecs / 1000,
+ total_secs, total_usecs / 1000);
+ else
+ elog(LOG, "checkpoint complete: wrote %d buffers (%.1f%%); "
+ "%d transaction log file(s) added, %d removed, %d recycled; "
+ "write=%ld.%03d s, sync=%ld.%03d s, total=%ld.%03d s",
+ CheckpointStats.ckpt_bufs_written,
+ (double) CheckpointStats.ckpt_bufs_written * 100 / NBuffers,
+ CheckpointStats.ckpt_segs_added,
+ CheckpointStats.ckpt_segs_removed,
+ CheckpointStats.ckpt_segs_recycled,
+ write_secs, write_usecs / 1000,
+ sync_secs, sync_usecs / 1000,
+ total_secs, total_usecs / 1000);
}
/*
TransactionId *inCommitXids;
int nInCommit;
+ /* shouldn't happen */
+ if (RecoveryInProgress())
+ elog(ERROR, "can't create a checkpoint during recovery");
+
/*
* Acquire CheckpointLock to ensure only one checkpoint happens at a time.
- * (This is just pro forma, since in the present system structure there is
- * only one process that is allowed to issue checkpoints at any given
- * time.)
+ * During normal operation, bgwriter is the only process that creates
+ * checkpoints, but at the end of archive recovery, the bgwriter can be
+ * busy creating a restartpoint while the startup process tries to perform
+ * the startup checkpoint.
*/
- LWLockAcquire(CheckpointLock, LW_EXCLUSIVE);
+ if (!LWLockConditionalAcquire(CheckpointLock, LW_EXCLUSIVE))
+ {
+ Assert(InRecovery);
+
+ /*
+ * A restartpoint is in progress. Wait until it finishes. This can
+ * cause an extra restartpoint to be performed, but that's OK because
+ * we're just about to perform a checkpoint anyway. Flushing the
+ * buffers in this restartpoint can take some time, but that time is
+ * saved from the upcoming checkpoint so the net effect is zero.
+ */
+ ereport(DEBUG2, (errmsg("hurrying in-progress restartpoint")));
+ RequestCheckpoint(CHECKPOINT_IMMEDIATE | CHECKPOINT_WAIT);
+
+ LWLockAcquire(CheckpointLock, LW_EXCLUSIVE);
+ }
/*
* Prepare to accumulate statistics.
if (shutdown)
{
+ LWLockAcquire(ControlFileLock, LW_EXCLUSIVE);
ControlFile->state = DB_SHUTDOWNING;
ControlFile->time = (pg_time_t) time(NULL);
UpdateControlFile();
+ LWLockRelease(ControlFileLock);
}
/*
* to log anything if we decided to skip the checkpoint.
*/
if (log_checkpoints)
- LogCheckpointStart(flags);
+ LogCheckpointStart(flags, false);
TRACE_POSTGRESQL_CHECKPOINT_START(flags);
/* All real work is done, but log before releasing lock. */
if (log_checkpoints)
- LogCheckpointEnd();
+ LogCheckpointEnd(false);
- TRACE_POSTGRESQL_CHECKPOINT_DONE(CheckpointStats.ckpt_bufs_written,
- NBuffers, CheckpointStats.ckpt_segs_added,
- CheckpointStats.ckpt_segs_removed,
- CheckpointStats.ckpt_segs_recycled);
+ TRACE_POSTGRESQL_CHECKPOINT_DONE(CheckpointStats.ckpt_bufs_written,
+ NBuffers,
+ CheckpointStats.ckpt_segs_added,
+ CheckpointStats.ckpt_segs_removed,
+ CheckpointStats.ckpt_segs_recycled);
LWLockRelease(CheckpointLock);
}
}
/*
- * Set a recovery restart point if appropriate
- *
- * This is similar to CreateCheckPoint, but is used during WAL recovery
- * to establish a point from which recovery can roll forward without
- * replaying the entire recovery log. This function is called each time
- * a checkpoint record is read from XLOG; it must determine whether a
- * restartpoint is needed or not.
+ * This is used during WAL recovery to establish a point from which recovery
+ * can roll forward without replaying the entire recovery log. This function
+ * is called each time a checkpoint record is read from XLOG. It is stored
+ * in shared memory, so that it can be used as a restartpoint later on.
*/
static void
RecoveryRestartPoint(const CheckPoint *checkPoint)
{
- int elapsed_secs;
int rmid;
-
- /*
- * Do nothing if the elapsed time since the last restartpoint is less than
- * half of checkpoint_timeout. (We use a value less than
- * checkpoint_timeout so that variations in the timing of checkpoints on
- * the master, or speed of transmission of WAL segments to a slave, won't
- * make the slave skip a restartpoint once it's synced with the master.)
- * Checking true elapsed time keeps us from doing restartpoints too often
- * while rapidly scanning large amounts of WAL.
- */
- elapsed_secs = (pg_time_t) time(NULL) - ControlFile->time;
- if (elapsed_secs < CheckPointTimeout / 2)
- return;
+ /* use volatile pointer to prevent code rearrangement */
+ volatile XLogCtlData *xlogctl = XLogCtl;
/*
* Is it safe to checkpoint? We must ask each of the resource managers
}
/*
- * OK, force data out to disk
+ * Copy the checkpoint record to shared memory, so that bgwriter can
+ * use it the next time it wants to perform a restartpoint.
*/
- CheckPointGuts(checkPoint->redo, CHECKPOINT_IMMEDIATE);
+ SpinLockAcquire(&xlogctl->info_lck);
+ XLogCtl->lastCheckPointRecPtr = ReadRecPtr;
+ memcpy(&XLogCtl->lastCheckPoint, checkPoint, sizeof(CheckPoint));
+ SpinLockRelease(&xlogctl->info_lck);
+}
+
+/*
+ * This is similar to CreateCheckPoint, but is used during WAL recovery
+ * to establish a point from which recovery can roll forward without
+ * replaying the entire recovery log.
+ *
+ * Returns true if a new restartpoint was established. We can only establish
+ * a restartpoint if we have replayed a checkpoint record since last
+ * restartpoint.
+ */
+bool
+CreateRestartPoint(int flags)
+{
+ XLogRecPtr lastCheckPointRecPtr;
+ CheckPoint lastCheckPoint;
+ /* use volatile pointer to prevent code rearrangement */
+ volatile XLogCtlData *xlogctl = XLogCtl;
/*
- * Update pg_control so that any subsequent crash will restart from this
- * checkpoint. Note: ReadRecPtr gives the XLOG address of the checkpoint
- * record itself.
+ * Acquire CheckpointLock to ensure only one restartpoint or checkpoint
+ * happens at a time.
*/
+ LWLockAcquire(CheckpointLock, LW_EXCLUSIVE);
+
+ /* Get the a local copy of the last checkpoint record. */
+ SpinLockAcquire(&xlogctl->info_lck);
+ lastCheckPointRecPtr = xlogctl->lastCheckPointRecPtr;
+ memcpy(&lastCheckPoint, &XLogCtl->lastCheckPoint, sizeof(CheckPoint));
+ SpinLockRelease(&xlogctl->info_lck);
+
+ /*
+ * Check that we're still in recovery mode. It's ok if we exit recovery
+ * mode after this check, the restart point is valid anyway.
+ */
+ if (!RecoveryInProgress())
+ {
+ ereport(DEBUG2,
+ (errmsg("skipping restartpoint, recovery has already ended")));
+ LWLockRelease(CheckpointLock);
+ return false;
+ }
+
+ /*
+ * If the last checkpoint record we've replayed is already our last
+ * restartpoint, we can't perform a new restart point. We still update
+ * minRecoveryPoint in that case, so that if this is a shutdown restart
+ * point, we won't start up earlier than before. That's not strictly
+ * necessary, but when we get hot standby capability, it would be rather
+ * weird if the database opened up for read-only connections at a
+ * point-in-time before the last shutdown. Such time travel is still
+ * possible in case of immediate shutdown, though.
+ *
+ * We don't explicitly advance minRecoveryPoint when we do create a
+ * restartpoint. It's assumed that flushing the buffers will do that
+ * as a side-effect.
+ */
+ if (XLogRecPtrIsInvalid(lastCheckPointRecPtr) ||
+ XLByteLE(lastCheckPoint.redo, ControlFile->checkPointCopy.redo))
+ {
+ XLogRecPtr InvalidXLogRecPtr = {0, 0};
+ ereport(DEBUG2,
+ (errmsg("skipping restartpoint, already performed at %X/%X",
+ lastCheckPoint.redo.xlogid, lastCheckPoint.redo.xrecoff)));
+
+ UpdateMinRecoveryPoint(InvalidXLogRecPtr, true);
+ LWLockRelease(CheckpointLock);
+ return false;
+ }
+
+ if (log_checkpoints)
+ {
+ /*
+ * Prepare to accumulate statistics.
+ */
+ MemSet(&CheckpointStats, 0, sizeof(CheckpointStats));
+ CheckpointStats.ckpt_start_t = GetCurrentTimestamp();
+
+ LogCheckpointStart(flags, true);
+ }
+
+ CheckPointGuts(lastCheckPoint.redo, flags);
+
+ /*
+ * Update pg_control, using current time
+ */
+ LWLockAcquire(ControlFileLock, LW_EXCLUSIVE);
ControlFile->prevCheckPoint = ControlFile->checkPoint;
- ControlFile->checkPoint = ReadRecPtr;
- ControlFile->checkPointCopy = *checkPoint;
+ ControlFile->checkPoint = lastCheckPointRecPtr;
+ ControlFile->checkPointCopy = lastCheckPoint;
ControlFile->time = (pg_time_t) time(NULL);
UpdateControlFile();
+ LWLockRelease(ControlFileLock);
+
+ /*
+ * Currently, there is no need to truncate pg_subtrans during recovery.
+ * If we did do that, we will need to have called StartupSUBTRANS()
+ * already and then TruncateSUBTRANS() would go here.
+ */
+
+ /* All real work is done, but log before releasing lock. */
+ if (log_checkpoints)
+ LogCheckpointEnd(true);
- ereport((recoveryLogRestartpoints ? LOG : DEBUG2),
+ ereport((log_checkpoints ? LOG : DEBUG2),
(errmsg("recovery restart point at %X/%X",
- checkPoint->redo.xlogid, checkPoint->redo.xrecoff)));
+ lastCheckPoint.redo.xlogid, lastCheckPoint.redo.xrecoff)));
+
if (recoveryLastXTime)
- ereport((recoveryLogRestartpoints ? LOG : DEBUG2),
- (errmsg("last completed transaction was at log time %s",
- timestamptz_to_str(recoveryLastXTime))));
+ ereport((log_checkpoints ? LOG : DEBUG2),
+ (errmsg("last completed transaction was at log time %s",
+ timestamptz_to_str(recoveryLastXTime))));
+
+ LWLockRelease(CheckpointLock);
+ return true;
}
/*
/*
* XLOG resource manager's routines
+ *
+ * Definitions of info values are in include/catalog/pg_control.h, though
+ * not all records types are related to control file processing.
*/
void
xlog_redo(XLogRecPtr lsn, XLogRecord *record)
{
uint8 info = record->xl_info & ~XLR_INFO_MASK;
+ /* Backup blocks are not used in xlog records */
+ Assert(!(record->xl_info & XLR_BKP_BLOCK_MASK));
+
if (info == XLOG_NEXTOID)
{
Oid nextOid;
(int) checkPoint.ThisTimeLineID))
ereport(PANIC,
(errmsg("unexpected timeline ID %u (after %u) in checkpoint record",
- checkPoint.ThisTimeLineID, ThisTimeLineID)));
- /* Following WAL records should be run with new TLI */
- ThisTimeLineID = checkPoint.ThisTimeLineID;
+ checkPoint.ThisTimeLineID, ThisTimeLineID)));
+ /* Following WAL records should be run with new TLI */
+ ThisTimeLineID = checkPoint.ThisTimeLineID;
}
RecoveryRestartPoint(&checkPoint);
pg_start_backup(PG_FUNCTION_ARGS)
{
text *backupid = PG_GETARG_TEXT_P(0);
+ bool fast = PG_GETARG_BOOL(1);
char *backupidstr;
XLogRecPtr checkpointloc;
XLogRecPtr startpoint;
XLogCtl->Insert.forcePageWrites = true;
LWLockRelease(WALInsertLock);
+ /*
+ * Force an XLOG file switch before the checkpoint, to ensure that the WAL
+ * segment the checkpoint is written to doesn't contain pages with old
+ * timeline IDs. That would otherwise happen if you called
+ * pg_start_backup() right after restoring from a PITR archive: the first
+ * WAL segment containing the startup checkpoint has pages in the
+ * beginning with the old timeline ID. That can cause trouble at recovery:
+ * we won't have a history file covering the old timeline if pg_xlog
+ * directory was not included in the base backup and the WAL archive was
+ * cleared too before starting the backup.
+ */
+ RequestXLogSwitch();
+
/* Ensure we release forcePageWrites if fail below */
PG_ENSURE_ERROR_CLEANUP(pg_start_backup_callback, (Datum) 0);
{
* have different checkpoint positions and hence different history
* file names, even if nothing happened in between.
*
- * We don't use CHECKPOINT_IMMEDIATE, hence this can take awhile.
+ * We use CHECKPOINT_IMMEDIATE only if requested by user (via
+ * passing fast = true). Otherwise this can take awhile.
*/
- RequestCheckpoint(CHECKPOINT_FORCE | CHECKPOINT_WAIT);
+ RequestCheckpoint(CHECKPOINT_FORCE | CHECKPOINT_WAIT |
+ (fast ? CHECKPOINT_IMMEDIATE : 0));
/*
* Now we need to fetch the checkpoint record location, and also its
}
}
+/* ------------------------------------------------------
+ * Startup Process main entry point and signal handlers
+ * ------------------------------------------------------
+ */
+
+/*
+ * startupproc_quickdie() occurs when signalled SIGQUIT by the postmaster.
+ *
+ * Some backend has bought the farm,
+ * so we need to stop what we're doing and exit.
+ */
+static void
+startupproc_quickdie(SIGNAL_ARGS)
+{
+ PG_SETMASK(&BlockSig);
+
+ /*
+ * DO NOT proc_exit() -- we're here because shared memory may be
+ * corrupted, so we don't want to try to clean up our transaction. Just
+ * nail the windows shut and get out of town.
+ *
+ * Note we do exit(2) not exit(0). This is to force the postmaster into a
+ * system reset cycle if some idiot DBA sends a manual SIGQUIT to a random
+ * backend. This is necessary precisely because we don't clean up our
+ * shared memory state.
+ */
+ exit(2);
+}
+
+
+/* SIGHUP: set flag to re-read config file at next convenient time */
+static void
+StartupProcSigHupHandler(SIGNAL_ARGS)
+{
+ got_SIGHUP = true;
+}
+
+/* SIGTERM: set flag to abort redo and exit */
+static void
+StartupProcShutdownHandler(SIGNAL_ARGS)
+{
+ if (in_restore_command)
+ proc_exit(1);
+ else
+ shutdown_requested = true;
+}
+
+/* Main entry point for startup process */
+void
+StartupProcessMain(void)
+{
+ /*
+ * If possible, make this process a group leader, so that the postmaster
+ * can signal any child processes too.
+ */
+#ifdef HAVE_SETSID
+ if (setsid() < 0)
+ elog(FATAL, "setsid() failed: %m");
+#endif
+
+ /*
+ * Properly accept or ignore signals the postmaster might send us
+ */
+ pqsignal(SIGHUP, StartupProcSigHupHandler); /* reload config file */
+ pqsignal(SIGINT, SIG_IGN); /* ignore query cancel */
+ pqsignal(SIGTERM, StartupProcShutdownHandler); /* request shutdown */
+ pqsignal(SIGQUIT, startupproc_quickdie); /* hard crash time */
+ pqsignal(SIGALRM, SIG_IGN);
+ pqsignal(SIGPIPE, SIG_IGN);
+ pqsignal(SIGUSR1, SIG_IGN);
+ pqsignal(SIGUSR2, SIG_IGN);
+
+ /*
+ * Reset some signals that are accepted by postmaster but not here
+ */
+ pqsignal(SIGCHLD, SIG_DFL);
+ pqsignal(SIGTTIN, SIG_DFL);
+ pqsignal(SIGTTOU, SIG_DFL);
+ pqsignal(SIGCONT, SIG_DFL);
+ pqsignal(SIGWINCH, SIG_DFL);
+
+ /*
+ * Unblock signals (they were blocked when the postmaster forked us)
+ */
+ PG_SETMASK(&UnBlockSig);
+
+ StartupXLOG();
+
+ BuildFlatFiles(false);
+
+ /*
+ * Exit normally. Exit code 0 tells postmaster that we completed
+ * recovery successfully.
+ */
+ proc_exit(0);
+}
OSDN Git Service
