diff options
Diffstat (limited to 'src/backend/access/transam/xlog.c')
| -rw-r--r-- | src/backend/access/transam/xlog.c | 112 |
1 files changed, 76 insertions, 36 deletions
diff --git a/src/backend/access/transam/xlog.c b/src/backend/access/transam/xlog.c index 74f92e3ef4..7e45beb41e 100644 --- a/src/backend/access/transam/xlog.c +++ b/src/backend/access/transam/xlog.c @@ -7,7 +7,7 @@ * Portions Copyright (c) 1996-2007, PostgreSQL Global Development Group * Portions Copyright (c) 1994, Regents of the University of California * - * $PostgreSQL: pgsql/src/backend/access/transam/xlog.c,v 1.272 2007/05/31 15:13:01 petere Exp $ + * $PostgreSQL: pgsql/src/backend/access/transam/xlog.c,v 1.273 2007/06/28 00:02:37 tgl Exp $ * *------------------------------------------------------------------------- */ @@ -72,16 +72,16 @@ bool XLOG_DEBUG = false; #endif /* - * XLOGfileslop is used in the code as the allowed "fuzz" in the number of - * preallocated XLOG segments --- we try to have at least XLOGfiles advance - * segments but no more than XLOGfileslop segments. This could - * be made a separate GUC variable, but at present I think it's sufficient - * to hardwire it as 2*CheckPointSegments+1. Under normal conditions, a - * checkpoint will free no more than 2*CheckPointSegments log segments, and - * we want to recycle all of them; the +1 allows boundary cases to happen - * without wasting a delete/create-segment cycle. + * XLOGfileslop is the maximum number of preallocated future XLOG segments. + * When we are done with an old XLOG segment file, we will recycle it as a + * future XLOG segment as long as there aren't already XLOGfileslop future + * segments; else we'll delete it. This could be made a separate GUC + * variable, but at present I think it's sufficient to hardwire it as + * 2*CheckPointSegments+1. Under normal conditions, a checkpoint will free + * no more than 2*CheckPointSegments log segments, and we want to recycle all + * of them; the +1 allows boundary cases to happen without wasting a + * delete/create-segment cycle. */ - #define XLOGfileslop (2*CheckPointSegments + 1) @@ -398,7 +398,7 @@ static void readRecoveryCommandFile(void); static void exitArchiveRecovery(TimeLineID endTLI, uint32 endLogId, uint32 endLogSeg); static bool recoveryStopsHere(XLogRecord *record, bool *includeThis); -static void CheckPointGuts(XLogRecPtr checkPointRedo); +static void CheckPointGuts(XLogRecPtr checkPointRedo, int flags); static bool XLogCheckBuffer(XLogRecData *rdata, bool doPageWrites, XLogRecPtr *lsn, BkpBlock *bkpb); @@ -415,7 +415,7 @@ static void XLogFileClose(void); static bool RestoreArchivedFile(char *path, const char *xlogfname, const char *recovername, off_t expectedSize); static int PreallocXlogFiles(XLogRecPtr endptr); -static void MoveOfflineLogs(uint32 log, uint32 seg, XLogRecPtr endptr, +static void RemoveOldXlogFiles(uint32 log, uint32 seg, XLogRecPtr endptr, int *nsegsremoved, int *nsegsrecycled); static void CleanupBackupHistory(void); static XLogRecord *ReadRecord(XLogRecPtr *RecPtr, int emode); @@ -1608,7 +1608,7 @@ XLogWrite(XLogwrtRqst WriteRqst, bool flexible, bool xlog_switch) if (XLOG_DEBUG) elog(LOG, "time for a checkpoint, signaling bgwriter"); #endif - RequestCheckpoint(false, true); + RequestCheckpoint(CHECKPOINT_WARNONTIME); } } } @@ -2516,8 +2516,14 @@ RestoreArchivedFile(char *path, const char *xlogfname, } /* - * Preallocate log files beyond the specified log endpoint, according to - * the XLOGfile user parameter. + * Preallocate log files beyond the specified log endpoint. + * + * XXX this is currently extremely conservative, since it forces only one + * future log segment to exist, and even that only if we are 75% done with + * the current one. This is only appropriate for very low-WAL-volume systems. + * High-volume systems will be OK once they've built up a sufficient set of + * recycled log segments, but the startup transient is likely to include + * a lot of segment creations by foreground processes, which is not so good. */ static int PreallocXlogFiles(XLogRecPtr endptr) @@ -2543,14 +2549,14 @@ PreallocXlogFiles(XLogRecPtr endptr) } /* - * Remove or move offline all log files older or equal to passed log/seg# + * Recycle or remove all log files older or equal to passed log/seg# * * endptr is current (or recent) end of xlog; this is used to determine * whether we want to recycle rather than delete no-longer-wanted log files. */ static void -MoveOfflineLogs(uint32 log, uint32 seg, XLogRecPtr endptr, - int *nsegsremoved, int *nsegsrecycled) +RemoveOldXlogFiles(uint32 log, uint32 seg, XLogRecPtr endptr, + int *nsegsremoved, int *nsegsrecycled) { uint32 endlogId; uint32 endlogSeg; @@ -5110,7 +5116,7 @@ StartupXLOG(void) * the rule that TLI only changes in shutdown checkpoints, which * allows some extra error checking in xlog_redo. */ - CreateCheckPoint(true, true); + CreateCheckPoint(CHECKPOINT_IS_SHUTDOWN | CHECKPOINT_IMMEDIATE); /* * Close down recovery environment @@ -5319,6 +5325,29 @@ GetRedoRecPtr(void) } /* + * GetInsertRecPtr -- Returns the current insert position. + * + * NOTE: The value *actually* returned is the position of the last full + * xlog page. It lags behind the real insert position by at most 1 page. + * For that, we don't need to acquire WALInsertLock which can be quite + * heavily contended, and an approximation is enough for the current + * usage of this function. + */ +XLogRecPtr +GetInsertRecPtr(void) +{ + /* use volatile pointer to prevent code rearrangement */ + volatile XLogCtlData *xlogctl = XLogCtl; + XLogRecPtr recptr; + + SpinLockAcquire(&xlogctl->info_lck); + recptr = xlogctl->LogwrtRqst.Write; + SpinLockRelease(&xlogctl->info_lck); + + return recptr; +} + +/* * Get the time of the last xlog segment switch */ time_t @@ -5383,7 +5412,7 @@ ShutdownXLOG(int code, Datum arg) ereport(LOG, (errmsg("shutting down"))); - CreateCheckPoint(true, true); + CreateCheckPoint(CHECKPOINT_IS_SHUTDOWN | CHECKPOINT_IMMEDIATE); ShutdownCLOG(); ShutdownSUBTRANS(); ShutdownMultiXact(); @@ -5395,12 +5424,21 @@ ShutdownXLOG(int code, Datum arg) /* * Perform a checkpoint --- either during shutdown, or on-the-fly * - * If force is true, we force a checkpoint regardless of whether any XLOG - * activity has occurred since the last one. + * flags is a bitwise OR of the following: + * CHECKPOINT_IS_SHUTDOWN: checkpoint is for database shutdown. + * CHECKPOINT_IMMEDIATE: finish the checkpoint ASAP, + * ignoring checkpoint_completion_target parameter. + * CHECKPOINT_FORCE: force a checkpoint even if no XLOG activity has occured + * since the last one (implied by CHECKPOINT_IS_SHUTDOWN). + * + * Note: flags might contain other bits of interest to RequestCheckpoint. + * In particular note that this routine is synchronous and does not pay + * attention to CHECKPOINT_WAIT. */ void -CreateCheckPoint(bool shutdown, bool force) +CreateCheckPoint(int flags) { + bool shutdown = (flags & CHECKPOINT_IS_SHUTDOWN) != 0; CheckPoint checkPoint; XLogRecPtr recptr; XLogCtlInsert *Insert = &XLogCtl->Insert; @@ -5459,7 +5497,7 @@ CreateCheckPoint(bool shutdown, bool force) * the end of the last checkpoint record, and its redo pointer must point * to itself. */ - if (!shutdown && !force) + if ((flags & (CHECKPOINT_IS_SHUTDOWN | CHECKPOINT_FORCE)) == 0) { XLogRecPtr curInsert; @@ -5591,7 +5629,7 @@ CreateCheckPoint(bool shutdown, bool force) */ END_CRIT_SECTION(); - CheckPointGuts(checkPoint.redo); + CheckPointGuts(checkPoint.redo, flags); START_CRIT_SECTION(); @@ -5650,24 +5688,24 @@ CreateCheckPoint(bool shutdown, bool force) /* * We are now done with critical updates; no need for system panic if we - * have trouble while fooling with offline log segments. + * have trouble while fooling with old log segments. */ END_CRIT_SECTION(); /* - * Delete offline log files (those no longer needed even for previous + * Delete old log files (those no longer needed even for previous * checkpoint). */ if (_logId || _logSeg) { PrevLogSeg(_logId, _logSeg); - MoveOfflineLogs(_logId, _logSeg, recptr, - &nsegsremoved, &nsegsrecycled); + RemoveOldXlogFiles(_logId, _logSeg, recptr, + &nsegsremoved, &nsegsrecycled); } /* - * Make more log segments if needed. (Do this after deleting offline log - * segments, to avoid having peak disk space usage higher than necessary.) + * Make more log segments if needed. (Do this after recycling old log + * segments, since that may supply some of the needed files.) */ if (!shutdown) nsegsadded = PreallocXlogFiles(recptr); @@ -5697,12 +5735,12 @@ CreateCheckPoint(bool shutdown, bool force) * recovery restartpoints. */ static void -CheckPointGuts(XLogRecPtr checkPointRedo) +CheckPointGuts(XLogRecPtr checkPointRedo, int flags) { CheckPointCLOG(); CheckPointSUBTRANS(); CheckPointMultiXact(); - FlushBufferPool(); /* performs all required fsyncs */ + CheckPointBuffers(flags); /* performs all required fsyncs */ /* We deliberately delay 2PC checkpointing as long as possible */ CheckPointTwoPhase(checkPointRedo); } @@ -5710,7 +5748,7 @@ CheckPointGuts(XLogRecPtr checkPointRedo) /* * Set a recovery restart point if appropriate * - * This is similar to CreateCheckpoint, but is used during WAL recovery + * 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 @@ -5751,7 +5789,7 @@ RecoveryRestartPoint(const CheckPoint *checkPoint) /* * OK, force data out to disk */ - CheckPointGuts(checkPoint->redo); + CheckPointGuts(checkPoint->redo, CHECKPOINT_IMMEDIATE); /* * Update pg_control so that any subsequent crash will restart from this @@ -6176,8 +6214,10 @@ pg_start_backup(PG_FUNCTION_ARGS) * page problems, this guarantees that two successive backup runs will * 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. */ - RequestCheckpoint(true, false); + RequestCheckpoint(CHECKPOINT_FORCE | CHECKPOINT_WAIT); /* * Now we need to fetch the checkpoint record location, and also its |