Thread
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[PATCH v5 1/3] Move code around in StartupXLOG().
Heikki Linnakangas <heikki.linnakangas@iki.fi> — 2021-07-31T12:06:32Z
This is the order that things will happen with the next commit, this makes it more explicit. To aid review, I added "BEGIN/END function" comments to mark which blocks of code are moved to separate functions in in the next commit. --- src/backend/access/transam/xlog.c | 469 ++++++++++++++++-------------- 1 file changed, 254 insertions(+), 215 deletions(-) diff --git a/src/backend/access/transam/xlog.c b/src/backend/access/transam/xlog.c index efb3ca273ed..7d30ef4de77 100644 --- a/src/backend/access/transam/xlog.c +++ b/src/backend/access/transam/xlog.c @@ -882,7 +882,6 @@ static MemoryContext walDebugCxt = NULL; static void readRecoverySignalFile(void); static void validateRecoveryParameters(void); -static void exitArchiveRecovery(TimeLineID endTLI, XLogRecPtr endOfLog); static bool recoveryStopsBefore(XLogReaderState *record); static bool recoveryStopsAfter(XLogReaderState *record); static char *getRecoveryStopReason(void); @@ -5593,10 +5592,10 @@ validateRecoveryParameters(void) } /* - * Exit archive-recovery state + * Initialize the first WAL segment on new timeline. */ static void -exitArchiveRecovery(TimeLineID endTLI, XLogRecPtr endOfLog) +XLogInitNewTimeline(TimeLineID endTLI, XLogRecPtr endOfLog) { char xlogfname[MAXFNAMELEN]; XLogSegNo endLogSegNo; @@ -5605,26 +5604,11 @@ exitArchiveRecovery(TimeLineID endTLI, XLogRecPtr endOfLog) /* we always switch to a new timeline after archive recovery */ Assert(endTLI != ThisTimeLineID); - /* - * We are no longer in archive recovery state. - */ - InArchiveRecovery = false; - /* * Update min recovery point one last time. */ UpdateMinRecoveryPoint(InvalidXLogRecPtr, true); - /* - * If the ending log segment is still open, close it (to avoid problems on - * Windows with trying to rename or delete an open file). - */ - if (readFile >= 0) - { - close(readFile); - readFile = -1; - } - /* * Calculate the last segment on the old timeline, and the first segment * on the new timeline. If the switch happens in the middle of a segment, @@ -5682,19 +5666,6 @@ exitArchiveRecovery(TimeLineID endTLI, XLogRecPtr endOfLog) */ XLogFileName(xlogfname, ThisTimeLineID, startLogSegNo, wal_segment_size); XLogArchiveCleanup(xlogfname); - - /* - * Remove the signal files out of the way, so that we don't accidentally - * re-enter archive recovery mode in a subsequent crash. - */ - if (standby_signal_file_found) - durable_unlink(STANDBY_SIGNAL_FILE, FATAL); - - if (recovery_signal_file_found) - durable_unlink(RECOVERY_SIGNAL_FILE, FATAL); - - ereport(LOG, - (errmsg("archive recovery complete"))); } /* @@ -6498,12 +6469,12 @@ StartupXLOG(void) checkPointLoc, EndOfLog; TimeLineID EndOfLogTLI; + char *recoveryStopReason; TimeLineID PrevTimeLineID; XLogRecord *record; TransactionId oldestActiveXID; bool backupEndRequired = false; bool backupFromStandby = false; - DBState dbstate_at_startup; XLogReaderState *xlogreader; XLogPageReadPrivate private; bool promoted = false; @@ -6611,6 +6582,8 @@ StartupXLOG(void) SyncDataDirectory(); } + /*---- BEGIN InitWalRecovery ----*/ + /* * Initialize on the assumption we want to recover to the latest timeline * that's active according to pg_control. @@ -6863,20 +6836,6 @@ StartupXLOG(void) wasShutdown = ((record->xl_info & ~XLR_INFO_MASK) == XLOG_CHECKPOINT_SHUTDOWN); } - /* - * Clear out any old relcache cache files. This is *necessary* if we do - * any WAL replay, since that would probably result in the cache files - * being out of sync with database reality. In theory we could leave them - * in place if the database had been cleanly shut down, but it seems - * safest to just remove them always and let them be rebuilt during the - * first backend startup. These files needs to be removed from all - * directories including pg_tblspc, however the symlinks are created only - * after reading tablespace_map file in case of archive recovery from - * backup, so needs to clear old relcache files here after creating - * symlinks. - */ - RelationCacheInitFileRemove(); - /* * If the location of the checkpoint record is not on the expected * timeline in the history of the requested timeline, we cannot proceed: @@ -6939,9 +6898,113 @@ StartupXLOG(void) (errmsg_internal("commit timestamp Xid oldest/newest: %u/%u", checkPoint.oldestCommitTsXid, checkPoint.newestCommitTsXid))); + + /* sanity checks on the checkpoint record */ if (!TransactionIdIsNormal(XidFromFullTransactionId(checkPoint.nextXid))) ereport(PANIC, (errmsg("invalid next transaction ID"))); + if (checkPoint.redo > checkPointLoc) + ereport(PANIC, + (errmsg("invalid redo in checkpoint record"))); + + /* + * Check whether we need to force recovery from WAL. If it appears to + * have been a clean shutdown and we did not have a recovery signal file, + * then assume no recovery needed. + */ + if (checkPoint.redo < checkPointLoc) + { + if (wasShutdown) + ereport(PANIC, + (errmsg("invalid redo record in shutdown checkpoint"))); + InRecovery = true; + } + else if (ControlFile->state != DB_SHUTDOWNED) + InRecovery = true; + else if (ArchiveRecoveryRequested) + { + /* force recovery due to presence of recovery signal file */ + InRecovery = true; + } + + /* + * If recovery is needed, update our in-memory copy of pg_control to show + * that we are recovering and to show the selected checkpoint as the place + * we are starting from. We also mark pg_control with any minimum recovery + * stop point obtained from a backup history file. + * + * We don't write the changes to disk yet, though. Only do that after + * initializing various subsystems. + */ + if (InRecovery) + { + DBState dbstate_at_startup; + + dbstate_at_startup = ControlFile->state; + if (InArchiveRecovery) + { + ControlFile->state = DB_IN_ARCHIVE_RECOVERY; + } + else + { + ereport(LOG, + (errmsg("database system was not properly shut down; " + "automatic recovery in progress"))); + if (recoveryTargetTLI > ControlFile->checkPointCopy.ThisTimeLineID) + ereport(LOG, + (errmsg("crash recovery starts in timeline %u " + "and has target timeline %u", + ControlFile->checkPointCopy.ThisTimeLineID, + recoveryTargetTLI))); + ControlFile->state = DB_IN_CRASH_RECOVERY; + } + ControlFile->checkPoint = checkPointLoc; + ControlFile->checkPointCopy = checkPoint; + if (InArchiveRecovery) + { + /* initialize minRecoveryPoint if not set yet */ + if (ControlFile->minRecoveryPoint < checkPoint.redo) + { + ControlFile->minRecoveryPoint = checkPoint.redo; + ControlFile->minRecoveryPointTLI = checkPoint.ThisTimeLineID; + } + } + + /* + * Set backupStartPoint if we're starting recovery from a base backup. + * + * Also set backupEndPoint and use minRecoveryPoint as the backup end + * location if we're starting recovery from a base backup which was + * taken from a standby. In this case, the database system status in + * pg_control must indicate that the database was already in recovery. + * Usually that will be DB_IN_ARCHIVE_RECOVERY but also can be + * DB_SHUTDOWNED_IN_RECOVERY if recovery previously was interrupted + * before reaching this point; e.g. because restore_command or + * primary_conninfo were faulty. + * + * Any other state indicates that the backup somehow became corrupted + * and we can't sensibly continue with recovery. + */ + if (haveBackupLabel) + { + ControlFile->backupStartPoint = checkPoint.redo; + ControlFile->backupEndRequired = backupEndRequired; + + if (backupFromStandby) + { + if (dbstate_at_startup != DB_IN_ARCHIVE_RECOVERY && + dbstate_at_startup != DB_SHUTDOWNED_IN_RECOVERY) + ereport(FATAL, + (errmsg("backup_label contains data inconsistent with control file"), + errhint("This means that the backup is corrupted and you will " + "have to use another backup for recovery."))); + ControlFile->backupEndPoint = ControlFile->minRecoveryPoint; + } + } + ControlFile->time = (pg_time_t) time(NULL); + } + + /*---- END InitWalRecovery ----*/ /* initialize shared memory variables from the checkpoint record */ ShmemVariableCache->nextXid = checkPoint.nextXid; @@ -6955,6 +7018,20 @@ StartupXLOG(void) checkPoint.newestCommitTsXid); XLogCtl->ckptFullXid = checkPoint.nextXid; + /* + * Clear out any old relcache cache files. This is *necessary* if we do + * any WAL replay, since that would probably result in the cache files + * being out of sync with database reality. In theory we could leave them + * in place if the database had been cleanly shut down, but it seems + * safest to just remove them always and let them be rebuilt during the + * first backend startup. These files needs to be removed from all + * directories including pg_tblspc, however the symlinks are created only + * after reading tablespace_map file in case of archive recovery from + * backup, so needs to clear old relcache files here after creating + * symlinks. + */ + RelationCacheInitFileRemove(); + /* * Initialize replication slots, before there's a chance to remove * required resources. @@ -7039,140 +7116,29 @@ StartupXLOG(void) RedoRecPtr = XLogCtl->RedoRecPtr = XLogCtl->Insert.RedoRecPtr = checkPoint.redo; doPageWrites = lastFullPageWrites; - if (RecPtr < checkPoint.redo) - ereport(PANIC, - (errmsg("invalid redo in checkpoint record"))); - - /* - * Check whether we need to force recovery from WAL. If it appears to - * have been a clean shutdown and we did not have a recovery signal file, - * then assume no recovery needed. - */ - if (checkPoint.redo < RecPtr) - { - if (wasShutdown) - ereport(PANIC, - (errmsg("invalid redo record in shutdown checkpoint"))); - InRecovery = true; - } - else if (ControlFile->state != DB_SHUTDOWNED) - InRecovery = true; - else if (ArchiveRecoveryRequested) - { - /* force recovery due to presence of recovery signal file */ - InRecovery = true; - } - /* REDO */ if (InRecovery) { int rmid; + /* Initialize state for RecoveryInProgress() */ + SpinLockAcquire(&XLogCtl->info_lck); + if (InArchiveRecovery) + XLogCtl->SharedRecoveryState = RECOVERY_STATE_ARCHIVE; + else + XLogCtl->SharedRecoveryState = RECOVERY_STATE_CRASH; + SpinLockRelease(&XLogCtl->info_lck); + /* * Update pg_control to show that we are recovering and to show the * selected checkpoint as the place we are starting from. We also mark * pg_control with any minimum recovery stop point obtained from a * backup history file. - */ - dbstate_at_startup = ControlFile->state; - if (InArchiveRecovery) - { - ControlFile->state = DB_IN_ARCHIVE_RECOVERY; - - SpinLockAcquire(&XLogCtl->info_lck); - XLogCtl->SharedRecoveryState = RECOVERY_STATE_ARCHIVE; - SpinLockRelease(&XLogCtl->info_lck); - } - else - { - ereport(LOG, - (errmsg("database system was not properly shut down; " - "automatic recovery in progress"))); - if (recoveryTargetTLI > ControlFile->checkPointCopy.ThisTimeLineID) - ereport(LOG, - (errmsg("crash recovery starts in timeline %u " - "and has target timeline %u", - ControlFile->checkPointCopy.ThisTimeLineID, - recoveryTargetTLI))); - ControlFile->state = DB_IN_CRASH_RECOVERY; - - SpinLockAcquire(&XLogCtl->info_lck); - XLogCtl->SharedRecoveryState = RECOVERY_STATE_CRASH; - SpinLockRelease(&XLogCtl->info_lck); - } - ControlFile->checkPoint = checkPointLoc; - ControlFile->checkPointCopy = checkPoint; - if (InArchiveRecovery) - { - /* initialize minRecoveryPoint if not set yet */ - if (ControlFile->minRecoveryPoint < checkPoint.redo) - { - ControlFile->minRecoveryPoint = checkPoint.redo; - ControlFile->minRecoveryPointTLI = checkPoint.ThisTimeLineID; - } - } - - /* - * Set backupStartPoint if we're starting recovery from a base backup. - * - * Also set backupEndPoint and use minRecoveryPoint as the backup end - * location if we're starting recovery from a base backup which was - * taken from a standby. In this case, the database system status in - * pg_control must indicate that the database was already in recovery. - * Usually that will be DB_IN_ARCHIVE_RECOVERY but also can be - * DB_SHUTDOWNED_IN_RECOVERY if recovery previously was interrupted - * before reaching this point; e.g. because restore_command or - * primary_conninfo were faulty. * - * Any other state indicates that the backup somehow became corrupted - * and we can't sensibly continue with recovery. + * No need to hold ControlFileLock yet, we aren't up far enough */ - if (haveBackupLabel) - { - ControlFile->backupStartPoint = checkPoint.redo; - ControlFile->backupEndRequired = backupEndRequired; - - if (backupFromStandby) - { - if (dbstate_at_startup != DB_IN_ARCHIVE_RECOVERY && - dbstate_at_startup != DB_SHUTDOWNED_IN_RECOVERY) - ereport(FATAL, - (errmsg("backup_label contains data inconsistent with control file"), - errhint("This means that the backup is corrupted and you will " - "have to use another backup for recovery."))); - ControlFile->backupEndPoint = ControlFile->minRecoveryPoint; - } - } - ControlFile->time = (pg_time_t) time(NULL); - /* No need to hold ControlFileLock yet, we aren't up far enough */ UpdateControlFile(); - /* - * Initialize our local copy of minRecoveryPoint. When doing crash - * recovery we want to replay up to the end of WAL. Particularly, in - * the case of a promoted standby minRecoveryPoint value in the - * control file is only updated after the first checkpoint. However, - * if the instance crashes before the first post-recovery checkpoint - * is completed then recovery will use a stale location causing the - * startup process to think that there are still invalid page - * references when checking for data consistency. - */ - if (InArchiveRecovery) - { - minRecoveryPoint = ControlFile->minRecoveryPoint; - minRecoveryPointTLI = ControlFile->minRecoveryPointTLI; - } - else - { - minRecoveryPoint = InvalidXLogRecPtr; - minRecoveryPointTLI = 0; - } - - /* - * 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 @@ -7200,6 +7166,32 @@ StartupXLOG(void) durable_rename(TABLESPACE_MAP, TABLESPACE_MAP_OLD, FATAL); } + /* + * Initialize our local copy of minRecoveryPoint. When doing crash + * recovery we want to replay up to the end of WAL. Particularly, in + * the case of a promoted standby minRecoveryPoint value in the + * control file is only updated after the first checkpoint. However, + * if the instance crashes before the first post-recovery checkpoint + * is completed then recovery will use a stale location causing the + * startup process to think that there are still invalid page + * references when checking for data consistency. + */ + if (InArchiveRecovery) + { + minRecoveryPoint = ControlFile->minRecoveryPoint; + minRecoveryPointTLI = ControlFile->minRecoveryPointTLI; + } + else + { + minRecoveryPoint = InvalidXLogRecPtr; + minRecoveryPointTLI = 0; + } + + /* + * Reset pgstat data, because it may be invalid after recovery. + */ + pgstat_reset_all(); + /* Check that the GUCs used to generate the WAL allow recovery */ CheckRequiredParameterValues(); @@ -7283,12 +7275,7 @@ StartupXLOG(void) } } - /* Initialize resource managers */ - for (rmid = 0; rmid <= RM_MAX_ID; rmid++) - { - if (RmgrTable[rmid].rm_startup != NULL) - RmgrTable[rmid].rm_startup(); - } + /*---- BEGIN PerformWalRecovery ----*/ /* * Initialize shared variables for tracking progress of WAL replay, as @@ -7296,7 +7283,7 @@ StartupXLOG(void) * checkpoint record itself, if it's a shutdown checkpoint). */ SpinLockAcquire(&XLogCtl->info_lck); - if (checkPoint.redo < RecPtr) + if (checkPoint.redo < checkPointLoc) XLogCtl->replayEndRecPtr = checkPoint.redo; else XLogCtl->replayEndRecPtr = EndRecPtr; @@ -7341,7 +7328,7 @@ StartupXLOG(void) * Find the first record that logically follows the checkpoint --- it * might physically precede it, though. */ - if (checkPoint.redo < RecPtr) + if (checkPoint.redo < checkPointLoc) { /* back up to find the record */ XLogBeginRead(xlogreader, checkPoint.redo); @@ -7350,6 +7337,7 @@ StartupXLOG(void) else { /* just have to read next record after CheckPoint */ + Assert(RecPtr == checkPointLoc); record = ReadRecord(xlogreader, LOG, false); } @@ -7363,6 +7351,13 @@ StartupXLOG(void) InRedo = true; + /* Initialize resource managers */ + for (rmid = 0; rmid <= RM_MAX_ID; rmid++) + { + if (RmgrTable[rmid].rm_startup != NULL) + RmgrTable[rmid].rm_startup(); + } + ereport(LOG, (errmsg("redo starts at %X/%X", LSN_FORMAT_ARGS(ReadRecPtr)))); @@ -7655,8 +7650,12 @@ StartupXLOG(void) !reachedRecoveryTarget) ereport(FATAL, (errmsg("recovery ended before configured recovery target was reached"))); + + /*---- END PerformWalRecovery ----*/ } + /*---- BEGIN FinishWalRecovery ----*/ + /* * Kill WAL receiver, if it's still running, before we continue to write * the startup checkpoint record. It will trump over the checkpoint and @@ -7664,23 +7663,6 @@ StartupXLOG(void) */ XLogShutdownWalRcv(); - /* - * Reset unlogged relations to the contents of their INIT fork. This is - * done AFTER recovery is complete so as to include any unlogged relations - * created during recovery, but BEFORE recovery is marked as having - * completed successfully. Otherwise we'd not retry if any of the post - * end-of-recovery steps fail. - */ - if (InRecovery) - ResetUnloggedRelations(UNLOGGED_RELATION_INIT); - - /* - * We don't need the latch anymore. It's not strictly necessary to disown - * it, but let's do it for the sake of tidiness. - */ - if (ArchiveRecoveryRequested) - DisownLatch(&XLogCtl->recoveryWakeupLatch); - /* * We are now done reading the xlog from stream. Turn off streaming * recovery to force fetching the files (which would be required at end of @@ -7709,6 +7691,32 @@ StartupXLOG(void) */ EndOfLogTLI = xlogreader->seg.ws_tli; + if (ArchiveRecoveryRequested) + { + /* + * We are no longer in archive recovery state. + * + * We are now done reading the old WAL. Turn off archive fetching if + * it was active. + */ + Assert(InArchiveRecovery); + InArchiveRecovery = false; + + /* + * If the ending log segment is still open, close it (to avoid problems on + * Windows with trying to rename or delete an open file). + */ + if (readFile >= 0) + { + close(readFile); + readFile = -1; + } + } + + recoveryStopReason = getRecoveryStopReason(); + + /*---- END FinishWalRecovery ----*/ + /* * Complain if we did not roll forward far enough to render the backup * dump consistent. Note: it is indeed okay to look at the local variable @@ -7745,6 +7753,16 @@ StartupXLOG(void) } } + /* + * Reset unlogged relations to the contents of their INIT fork. This is + * done AFTER recovery is complete so as to include any unlogged relations + * created during recovery, but BEFORE recovery is marked as having + * completed successfully. Otherwise we'd not retry if any of the post + * end-of-recovery steps fail. + */ + if (InRecovery) + ResetUnloggedRelations(UNLOGGED_RELATION_INIT); + /* * Pre-scan prepared transactions to find out the range of XIDs present. * This information is not quite needed yet, but it is positioned here so @@ -7753,8 +7771,8 @@ StartupXLOG(void) oldestActiveXID = PrescanPreparedTransactions(NULL, NULL); /* - * Allow ordinary WAL segment creation before any exitArchiveRecovery(), - * which sometimes creates a segment, and after the last ReadRecord(). + * Allow ordinary WAL segment creation before switching to a new timeline, + * which creates a new segment, and after the last ReadRecord(). */ LWLockAcquire(ControlFileLock, LW_EXCLUSIVE); XLogCtl->InstallXLogFileSegmentActive = true; @@ -7777,24 +7795,26 @@ StartupXLOG(void) PrevTimeLineID = ThisTimeLineID; if (ArchiveRecoveryRequested) { - char *reason; - char recoveryPath[MAXPGPATH]; - - Assert(InArchiveRecovery); - ThisTimeLineID = findNewestTimeLine(recoveryTargetTLI) + 1; ereport(LOG, (errmsg("selected new timeline ID: %u", ThisTimeLineID))); - reason = getRecoveryStopReason(); + /* + * Make a writable copy of the last WAL segment. (Note that we also + * have a copy of the last block of the old WAL in readBuf; we will + * use that below.) + */ + XLogInitNewTimeline(EndOfLogTLI, EndOfLog); /* - * We are now done reading the old WAL. Turn off archive fetching if - * it was active, and make a writable copy of the last WAL segment. - * (Note that we also have a copy of the last block of the old WAL in - * readBuf; we will use that below.) + * Remove the signal files out of the way, so that we don't accidentally + * re-enter archive recovery mode in a subsequent crash. */ - exitArchiveRecovery(EndOfLogTLI, EndOfLog); + if (standby_signal_file_found) + durable_unlink(STANDBY_SIGNAL_FILE, FATAL); + + if (recovery_signal_file_found) + durable_unlink(RECOVERY_SIGNAL_FILE, FATAL); /* * Write the timeline history file, and have it archived. After this @@ -7807,18 +7827,10 @@ StartupXLOG(void) * between here and writing the end-of-recovery record. */ writeTimeLineHistory(ThisTimeLineID, recoveryTargetTLI, - EndRecPtr, reason); + EndOfLog, recoveryStopReason); - /* - * Since there might be a partial WAL segment named RECOVERYXLOG, get - * rid of it. - */ - snprintf(recoveryPath, MAXPGPATH, XLOGDIR "/RECOVERYXLOG"); - unlink(recoveryPath); /* ignore any error */ - - /* Get rid of any remaining recovered timeline-history file, too */ - snprintf(recoveryPath, MAXPGPATH, XLOGDIR "/RECOVERYHISTORY"); - unlink(recoveryPath); /* ignore any error */ + ereport(LOG, + (errmsg("archive recovery complete"))); } /* Save the selected TimeLineID in shared memory, too */ @@ -8054,6 +8066,8 @@ StartupXLOG(void) if (standbyState != STANDBY_DISABLED) ShutdownRecoveryTransactionEnvironment(); + /*---- BEGIN FreeWalRecovery ----*/ + /* Shut down xlogreader */ if (readFile >= 0) { @@ -8062,6 +8076,31 @@ StartupXLOG(void) } XLogReaderFree(xlogreader); + if (ArchiveRecoveryRequested) + { + char recoveryPath[MAXPGPATH]; + + /* + * Since there might be a partial WAL segment named RECOVERYXLOG, get + * rid of it. + */ + snprintf(recoveryPath, MAXPGPATH, XLOGDIR "/RECOVERYXLOG"); + unlink(recoveryPath); /* ignore any error */ + + /* Get rid of any remaining recovered timeline-history file, too */ + snprintf(recoveryPath, MAXPGPATH, XLOGDIR "/RECOVERYHISTORY"); + unlink(recoveryPath); /* ignore any error */ + } + + /* + * We don't need the latch anymore. It's not strictly necessary to disown + * it, but let's do it for the sake of tidiness. + */ + if (ArchiveRecoveryRequested) + DisownLatch(&XLogCtl->recoveryWakeupLatch); + + /*---- END FreeWalRecovery ----*/ + /* * If any of the critical GUCs have changed, log them before we allow * backends to write WAL. -- 2.30.2 --------------F589ECF1004AF34308A0B206 Content-Type: text/x-patch; charset=UTF-8; name="v5-0002-Split-xlog.c-into-xlog.c-and-xlogrecovery.c.patch" Content-Transfer-Encoding: 7bit Content-Disposition: attachment; filename*0="v5-0002-Split-xlog.c-into-xlog.c-and-xlogrecovery.c.patch"