]> git.ipfire.org Git - thirdparty/postgresql.git/commitdiff
Revert "Avoid creating archive status ".ready" files too early"
authorAlvaro Herrera <alvherre@alvh.no-ip.org>
Sat, 4 Sep 2021 16:14:30 +0000 (12:14 -0400)
committerAlvaro Herrera <alvherre@alvh.no-ip.org>
Sat, 4 Sep 2021 16:14:30 +0000 (12:14 -0400)
This reverts commit 515e3d84a0b5 and equivalent commits in back
branches.  This solution to the problem has a number of problems, so
we'll try again with a different approach.

Per note from Andres Freund

Discussion: https://postgr.es/m/20210831042949.52eqp5xwbxgrfank@alap3.anarazel.de

src/backend/access/transam/xlog.c
src/backend/postmaster/walwriter.c
src/include/access/xlog.h
src/include/access/xlogdefs.h

index dbe4f58cb9dfe34fd4f90508de0c570d54fa4c42..e84f6ed2ff121ed83ce54ff16bb3fa9aeda40582 100644 (file)
@@ -733,18 +733,6 @@ typedef struct XLogCtlData
        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;
@@ -943,7 +931,6 @@ static void RemoveXlogFile(const char *segname, XLogSegNo recycleSegNo,
                                                   XLogSegNo *endlogSegNo);
 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,
@@ -1178,56 +1165,23 @@ XLogInsertRecord(XLogRecData *rdata,
        END_CRIT_SECTION();
 
        /*
-        * If we crossed page boundary, update LogwrtRqst.Write; if we crossed
-        * segment boundary, register that and wake up walwriter.
+        * Update shared LogwrtRqst.Write, if we crossed page boundary.
         */
        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.
+        * padding space that fills the rest of the segment, and perform
+        * end-of-segment actions (eg, notifying archiver).
         */
        if (isLogSwitch)
        {
@@ -2479,7 +2433,6 @@ XLogWrite(XLogwrtRqst WriteRqst, bool flexible)
 
        /* We should always be inside a critical section here */
        Assert(CritSectionCount > 0);
-       Assert(LWLockHeldByMe(WALWriteLock));
 
        /*
         * Update local LogwrtResult (caller probably did this already, but...)
@@ -2646,12 +2599,11 @@ XLogWrite(XLogwrtRqst WriteRqst, bool flexible)
                         * later. Doing it here ensures that one and only one backend will
                         * perform this fsync.
                         *
-                        * 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.
+                        * 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 (finishing_seg)
                        {
@@ -2663,7 +2615,7 @@ XLogWrite(XLogwrtRqst WriteRqst, bool flexible)
                                LogwrtResult.Flush = LogwrtResult.Write;        /* end of page */
 
                                if (XLogArchivingActive())
-                                       NotifySegmentsReadyForArchive(LogwrtResult.Flush);
+                                       XLogArchiveNotifySeg(openLogSegNo);
 
                                XLogCtl->lastSegSwitchTime = (pg_time_t) time(NULL);
                                XLogCtl->lastSegSwitchLSN = LogwrtResult.Flush;
@@ -2751,9 +2703,6 @@ XLogWrite(XLogwrtRqst WriteRqst, bool flexible)
                        XLogCtl->LogwrtRqst.Flush = LogwrtResult.Flush;
                SpinLockRelease(&XLogCtl->info_lck);
        }
-
-       if (XLogArchivingActive())
-               NotifySegmentsReadyForArchive(LogwrtResult.Flush);
 }
 
 /*
@@ -4375,129 +4324,6 @@ ValidateXLOGDirectoryStructure(void)
        }
 }
 
-/*
- * 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
@@ -5399,17 +5225,9 @@ XLOGShmemInit(void)
 
        SpinLockInit(&XLogCtl->Insert.insertpos_lck);
        SpinLockInit(&XLogCtl->info_lck);
-       SpinLockInit(&XLogCtl->segtrack_lck);
        SpinLockInit(&XLogCtl->ulsn_lck);
        InitSharedLatch(&XLogCtl->recoveryWakeupLatch);
        ConditionVariableInit(&XLogCtl->recoveryNotPausedCV);
-
-       /* Initialize stuff for marking segments as ready for archival. */
-       XLogCtl->lastNotifiedSeg = MaxXLogSegNo;
-       XLogCtl->earliestSegBoundary = MaxXLogSegNo;
-       XLogCtl->earliestSegBoundaryEndPtr = InvalidXLogRecPtr;
-       XLogCtl->latestSegBoundary = MaxXLogSegNo;
-       XLogCtl->latestSegBoundaryEndPtr = InvalidXLogRecPtr;
 }
 
 /*
@@ -8040,20 +7858,6 @@ StartupXLOG(void)
        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
index 6a1e16edc23ab806f1321b26d4458f0845706ccb..626fae8454ca4d38cacc9fd4e6c82ce596990908 100644 (file)
@@ -248,13 +248,6 @@ WalWriterMain(void)
                /* Process any signals received recently */
                HandleWalWriterInterrupts();
 
-               /*
-                * Notify the archiver of any WAL segments that are ready.  We do this
-                * here to handle a race condition where WAL is flushed to disk prior
-                * to registering the segment boundary.
-                */
-               NotifySegmentsReadyForArchive(GetFlushRecPtr());
-
                /*
                 * Do what we're here for; then, if XLogBackgroundFlush() found useful
                 * work to do, reset hibernation counter.
index 80ad3306a7877aa9959fb966799d0c041a057ad5..77187c12bebac7f4abf5790c61b966f543326889 100644 (file)
@@ -349,7 +349,6 @@ extern XLogRecPtr GetInsertRecPtr(void);
 extern XLogRecPtr GetFlushRecPtr(void);
 extern XLogRecPtr GetLastImportantRecPtr(void);
 extern void RemovePromoteSignalFiles(void);
-extern void NotifySegmentsReadyForArchive(XLogRecPtr flushRecPtr);
 
 extern bool PromoteIsTriggered(void);
 extern bool CheckPromoteSignal(void);
index 9110d3dfa8bd06d90d9a46dccf6f00d18ecefbfb..0940b64ca6bef63956d1863885d9781088e99723 100644 (file)
@@ -46,7 +46,6 @@ typedef uint64 XLogRecPtr;
  * XLogSegNo - physical log file sequence number.
  */
 typedef uint64 XLogSegNo;
-#define MaxXLogSegNo   ((XLogSegNo) 0xFFFFFFFFFFFFFFFF)
 
 /*
  * TimeLineID (TLI) - identifies different database histories to prevent