XLogRecPtr lastFpwDisableRecPtr;
slock_t info_lck; /* locks shared variables shown above */
+
+ /*
+ * Variables used to track segment-boundary-crossing WAL records. See
+ * RegisterSegmentBoundary. Protected by segtrack_lck.
+ */
+ XLogSegNo lastNotifiedSeg;
+ XLogSegNo earliestSegBoundary;
+ XLogRecPtr earliestSegBoundaryEndPtr;
+ XLogSegNo latestSegBoundary;
+ XLogRecPtr latestSegBoundaryEndPtr;
+
+ slock_t segtrack_lck; /* locks shared variables shown above */
} XLogCtlData;
static XLogCtlData *XLogCtl = NULL;
static void RemoveXlogFile(const char *segname, XLogRecPtr lastredoptr, XLogRecPtr endptr);
static void UpdateLastRemovedPtr(char *filename);
static void ValidateXLOGDirectoryStructure(void);
+static void RegisterSegmentBoundary(XLogSegNo seg, XLogRecPtr pos);
static void CleanupBackupHistory(void);
static void UpdateMinRecoveryPoint(XLogRecPtr lsn, bool force);
static XLogRecord *ReadRecord(XLogReaderState *xlogreader, XLogRecPtr RecPtr,
END_CRIT_SECTION();
/*
- * Update shared LogwrtRqst.Write, if we crossed page boundary.
+ * If we crossed page boundary, update LogwrtRqst.Write; if we crossed
+ * segment boundary, register that and wake up walwriter.
*/
if (StartPos / XLOG_BLCKSZ != EndPos / XLOG_BLCKSZ)
{
+ XLogSegNo StartSeg;
+ XLogSegNo EndSeg;
+
+ XLByteToSeg(StartPos, StartSeg, wal_segment_size);
+ XLByteToSeg(EndPos, EndSeg, wal_segment_size);
+
+ /*
+ * Register our crossing the segment boundary if that occurred.
+ *
+ * Note that we did not use XLByteToPrevSeg() for determining the
+ * ending segment. This is so that a record that fits perfectly into
+ * the end of the segment causes the latter to get marked ready for
+ * archival immediately.
+ */
+ if (StartSeg != EndSeg && XLogArchivingActive())
+ RegisterSegmentBoundary(EndSeg, EndPos);
+
+ /*
+ * Advance LogwrtRqst.Write so that it includes new block(s).
+ *
+ * We do this after registering the segment boundary so that the
+ * comparison with the flushed pointer below can use the latest value
+ * known globally.
+ */
SpinLockAcquire(&XLogCtl->info_lck);
- /* advance global request to include new block(s) */
if (XLogCtl->LogwrtRqst.Write < EndPos)
XLogCtl->LogwrtRqst.Write = EndPos;
/* update local result copy while I have the chance */
LogwrtResult = XLogCtl->LogwrtResult;
SpinLockRelease(&XLogCtl->info_lck);
+
+ /*
+ * There's a chance that the record was already flushed to disk and we
+ * missed marking segments as ready for archive. If this happens, we
+ * nudge the WALWriter, which will take care of notifying segments as
+ * needed.
+ */
+ if (StartSeg != EndSeg && XLogArchivingActive() &&
+ LogwrtResult.Flush >= EndPos && ProcGlobal->walwriterLatch)
+ SetLatch(ProcGlobal->walwriterLatch);
}
/*
* If this was an XLOG_SWITCH record, flush the record and the empty
- * padding space that fills the rest of the segment, and perform
- * end-of-segment actions (eg, notifying archiver).
+ * padding space that fills the rest of the segment.
*/
if (isLogSwitch)
{
/* We should always be inside a critical section here */
Assert(CritSectionCount > 0);
+ Assert(LWLockHeldByMe(WALWriteLock));
/*
* Update local LogwrtResult (caller probably did this already, but...)
* later. Doing it here ensures that one and only one backend will
* perform this fsync.
*
- * This is also the right place to notify the Archiver that the
- * segment is ready to copy to archival storage, and to update the
- * timer for archive_timeout, and to signal for a checkpoint if
- * too many logfile segments have been used since the last
- * checkpoint.
+ * If WAL archiving is active, we attempt to notify the archiver
+ * of any segments that are now ready for archival.
+ *
+ * This is also the right place to update the timer for
+ * archive_timeout and to signal for a checkpoint if too many
+ * logfile segments have been used since the last checkpoint.
*/
if (finishing_seg)
{
LogwrtResult.Flush = LogwrtResult.Write; /* end of page */
if (XLogArchivingActive())
- XLogArchiveNotifySeg(openLogSegNo);
+ NotifySegmentsReadyForArchive(LogwrtResult.Flush);
XLogCtl->lastSegSwitchTime = (pg_time_t) time(NULL);
XLogCtl->lastSegSwitchLSN = LogwrtResult.Flush;
XLogCtl->LogwrtRqst.Flush = LogwrtResult.Flush;
SpinLockRelease(&XLogCtl->info_lck);
}
+
+ if (XLogArchivingActive())
+ NotifySegmentsReadyForArchive(LogwrtResult.Flush);
}
/*
}
}
+/*
+ * RegisterSegmentBoundary
+ *
+ * WAL records that are split across a segment boundary require special
+ * treatment for archiving: the initial segment must not be archived until
+ * the end segment has been flushed, in case we crash before we have
+ * the chance to flush the end segment (because after recovery we would
+ * overwrite that WAL record with a different one, and so the file we
+ * archived no longer represents truth.) This also applies to streaming
+ * physical replication.
+ *
+ * To handle this, we keep track of the LSN of WAL records that cross
+ * segment boundaries. Two such are sufficient: the ones with the
+ * earliest and the latest end pointers we know about, since the flush
+ * position advances monotonically. WAL record writers register
+ * boundary-crossing records here, which is used by .ready file creation
+ * to delay until the end segment is known flushed.
+ */
+static void
+RegisterSegmentBoundary(XLogSegNo seg, XLogRecPtr endpos)
+{
+ XLogSegNo segno PG_USED_FOR_ASSERTS_ONLY;
+
+ /* verify caller computed segment number correctly */
+ AssertArg((XLByteToSeg(endpos, segno, wal_segment_size), segno == seg));
+
+ SpinLockAcquire(&XLogCtl->segtrack_lck);
+
+ /*
+ * If no segment boundaries are registered, store the new segment boundary
+ * in earliestSegBoundary. Otherwise, store the greater segment
+ * boundaries in latestSegBoundary.
+ */
+ if (XLogCtl->earliestSegBoundary == MaxXLogSegNo)
+ {
+ XLogCtl->earliestSegBoundary = seg;
+ XLogCtl->earliestSegBoundaryEndPtr = endpos;
+ }
+ else if (seg > XLogCtl->earliestSegBoundary &&
+ (XLogCtl->latestSegBoundary == MaxXLogSegNo ||
+ seg > XLogCtl->latestSegBoundary))
+ {
+ XLogCtl->latestSegBoundary = seg;
+ XLogCtl->latestSegBoundaryEndPtr = endpos;
+ }
+
+ SpinLockRelease(&XLogCtl->segtrack_lck);
+}
+
+/*
+ * NotifySegmentsReadyForArchive
+ *
+ * Mark segments as ready for archival, given that it is safe to do so.
+ * This function is idempotent.
+ */
+void
+NotifySegmentsReadyForArchive(XLogRecPtr flushRecPtr)
+{
+ XLogSegNo latest_boundary_seg;
+ XLogSegNo last_notified;
+ XLogSegNo flushed_seg;
+ XLogSegNo seg;
+ bool keep_latest;
+
+ XLByteToSeg(flushRecPtr, flushed_seg, wal_segment_size);
+
+ SpinLockAcquire(&XLogCtl->segtrack_lck);
+
+ if (XLogCtl->latestSegBoundary <= flushed_seg &&
+ XLogCtl->latestSegBoundaryEndPtr <= flushRecPtr)
+ {
+ latest_boundary_seg = XLogCtl->latestSegBoundary;
+ keep_latest = false;
+ }
+ else if (XLogCtl->earliestSegBoundary <= flushed_seg &&
+ XLogCtl->earliestSegBoundaryEndPtr <= flushRecPtr)
+ {
+ latest_boundary_seg = XLogCtl->earliestSegBoundary;
+ keep_latest = true;
+ }
+ else
+ {
+ SpinLockRelease(&XLogCtl->segtrack_lck);
+ return;
+ }
+
+ last_notified = XLogCtl->lastNotifiedSeg;
+
+ /*
+ * Update shared memory and discard segment boundaries that are no longer
+ * needed.
+ *
+ * It is safe to update shared memory before we attempt to create the
+ * .ready files. If our calls to XLogArchiveNotifySeg() fail,
+ * RemoveOldXlogFiles() will retry it as needed.
+ */
+ if (last_notified < latest_boundary_seg - 1)
+ XLogCtl->lastNotifiedSeg = latest_boundary_seg - 1;
+
+ if (keep_latest)
+ {
+ XLogCtl->earliestSegBoundary = XLogCtl->latestSegBoundary;
+ XLogCtl->earliestSegBoundaryEndPtr = XLogCtl->latestSegBoundaryEndPtr;
+ }
+ else
+ {
+ XLogCtl->earliestSegBoundary = MaxXLogSegNo;
+ XLogCtl->earliestSegBoundaryEndPtr = InvalidXLogRecPtr;
+ }
+
+ XLogCtl->latestSegBoundary = MaxXLogSegNo;
+ XLogCtl->latestSegBoundaryEndPtr = InvalidXLogRecPtr;
+
+ SpinLockRelease(&XLogCtl->segtrack_lck);
+
+ /*
+ * Notify archiver about segments that are ready for archival (by creating
+ * the corresponding .ready files).
+ */
+ for (seg = last_notified + 1; seg < latest_boundary_seg; seg++)
+ XLogArchiveNotifySeg(seg);
+}
+
/*
* Remove previous backup history files. This also retries creation of
* .ready files for any backup history files for which XLogArchiveNotify
SpinLockInit(&XLogCtl->Insert.insertpos_lck);
SpinLockInit(&XLogCtl->info_lck);
+ SpinLockInit(&XLogCtl->segtrack_lck);
SpinLockInit(&XLogCtl->ulsn_lck);
InitSharedLatch(&XLogCtl->recoveryWakeupLatch);
+
+ /* Initialize stuff for marking segments as ready for archival. */
+ XLogCtl->lastNotifiedSeg = MaxXLogSegNo;
+ XLogCtl->earliestSegBoundary = MaxXLogSegNo;
+ XLogCtl->earliestSegBoundaryEndPtr = InvalidXLogRecPtr;
+ XLogCtl->latestSegBoundary = MaxXLogSegNo;
+ XLogCtl->latestSegBoundaryEndPtr = InvalidXLogRecPtr;
}
/*
XLogCtl->LogwrtRqst.Write = EndOfLog;
XLogCtl->LogwrtRqst.Flush = EndOfLog;
+ /*
+ * Initialize XLogCtl->lastNotifiedSeg to the previous WAL file.
+ */
+ if (XLogArchivingActive())
+ {
+ XLogSegNo EndOfLogSeg;
+
+ XLByteToSeg(EndOfLog, EndOfLogSeg, wal_segment_size);
+
+ SpinLockAcquire(&XLogCtl->segtrack_lck);
+ XLogCtl->lastNotifiedSeg = EndOfLogSeg - 1;
+ SpinLockRelease(&XLogCtl->segtrack_lck);
+ }
+
/*
* Update full_page_writes in shared memory and write an XLOG_FPW_CHANGE
* record before resource manager writes cleanup WAL records or checkpoint
projects / thirdparty / postgresql.git / commitdiff
