Movatterモバイル変換

[0]ホーム
URL:

Skip to content

Navigation Menu

Sign in
Appearance settings

Search code, repositories, users, issues, pull requests...

Provide feedback

We read every piece of feedback, and take your input very seriously.

Saved searches

Use saved searches to filter your results more quickly

 Sign up
Appearance settings

Commit1f09121

Browse files
Ensure no xid gaps during Hot Standby startup
In some cases with higher numbers of subtransactionsit was possible for us to incorrectly initializesubtrans leading to complaints of missing pages.Bug report by Sergey KonoplevAnalysis and fix by Andres Freund
1 parentdab1603 commit1f09121

File tree

3 files changed

+51
-6
lines changed

3 files changed

+51
-6
lines changed

‎src/backend/access/transam/xlog.c

Lines changed: 3 additions & 0 deletions
Original file line numberDiff line numberDiff line change
@@ -5391,6 +5391,9 @@ StartupXLOG(void)
53915391
oldestActiveXID=checkPoint.oldestActiveXid;
53925392
Assert(TransactionIdIsValid(oldestActiveXID));
53935393

5394+
/* Tell procarray about the range of xids it has to deal with */
5395+
ProcArrayInitRecovery(ShmemVariableCache->nextXid);
5396+
53945397
/*
53955398
* Startup commit log and subtrans only. Other SLRUs are not
53965399
* maintained during recovery and need not be started yet.

‎src/backend/storage/ipc/procarray.c

Lines changed: 47 additions & 6 deletions
Original file line numberDiff line numberDiff line change
@@ -469,6 +469,28 @@ ProcArrayClearTransaction(PGPROC *proc)
469469
pgxact->overflowed= false;
470470
}
471471

472+
/*
473+
* ProcArrayInitRecovery -- initialize recovery xid mgmt environment
474+
*
475+
* Remember up to where the startup process initialized the CLOG and subtrans
476+
* so we can ensure its initialized gaplessly up to the point where necessary
477+
* while in recovery.
478+
*/
479+
void
480+
ProcArrayInitRecovery(TransactionIdinitializedUptoXID)
481+
{
482+
Assert(standbyState==STANDBY_INITIALIZED);
483+
Assert(TransactionIdIsNormal(initializedUptoXID));
484+
485+
/*
486+
* we set latestObservedXid to the xid SUBTRANS has been initialized upto
487+
* so we can extend it from that point onwards when we reach a consistent
488+
* state in ProcArrayApplyRecoveryInfo().
489+
*/
490+
latestObservedXid=initializedUptoXID;
491+
TransactionIdRetreat(latestObservedXid);
492+
}
493+
472494
/*
473495
* ProcArrayApplyRecoveryInfo -- apply recovery info about xids
474496
*
@@ -564,7 +586,10 @@ ProcArrayApplyRecoveryInfo(RunningTransactions running)
564586
Assert(standbyState==STANDBY_INITIALIZED);
565587

566588
/*
567-
* OK, we need to initialise from the RunningTransactionsData record
589+
* OK, we need to initialise from the RunningTransactionsData record.
590+
*
591+
* NB: this can be reached at least twice, so make sure new code can deal
592+
* with that.
568593
*/
569594

570595
/*
@@ -636,20 +661,32 @@ ProcArrayApplyRecoveryInfo(RunningTransactions running)
636661
pfree(xids);
637662

638663
/*
664+
* latestObservedXid is set to the the point where SUBTRANS was started up
665+
* to, initialize subtrans from thereon, up to nextXid - 1.
666+
*/
667+
Assert(TransactionIdIsNormal(latestObservedXid));
668+
while (TransactionIdPrecedes(latestObservedXid,running->nextXid))
669+
{
670+
ExtendCLOG(latestObservedXid);
671+
ExtendSUBTRANS(latestObservedXid);
672+
673+
TransactionIdAdvance(latestObservedXid);
674+
}
675+
676+
/* ----------
639677
* Now we've got the running xids we need to set the global values that
640678
* are used to track snapshots as they evolve further.
641679
*
642-
* - latestCompletedXid which will be the xmax for snapshots -
643-
* lastOverflowedXid which shows whether snapshots overflow - nextXid
680+
* - latestCompletedXid which will be the xmax for snapshots
681+
* - lastOverflowedXid which shows whether snapshots overflow
682+
* - nextXid
644683
*
645684
* If the snapshot overflowed, then we still initialise with what we know,
646685
* but the recovery snapshot isn't fully valid yet because we know there
647686
* are some subxids missing. We don't know the specific subxids that are
648687
* missing, so conservatively assume the last one is latestObservedXid.
688+
* ----------
649689
*/
650-
latestObservedXid=running->nextXid;
651-
TransactionIdRetreat(latestObservedXid);
652-
653690
if (running->subxid_overflow)
654691
{
655692
standbyState=STANDBY_SNAPSHOT_PENDING;
@@ -719,6 +756,10 @@ ProcArrayApplyXidAssignment(TransactionId topxid,
719756

720757
Assert(standbyState >=STANDBY_INITIALIZED);
721758

759+
/* can't do anything useful unless we have more state setup */
760+
if (standbyState==STANDBY_INITIALIZED)
761+
return;
762+
722763
max_xid=TransactionIdLatest(topxid,nsubxids,subxids);
723764

724765
/*

‎src/include/storage/procarray.h

Lines changed: 1 addition & 0 deletions
Original file line numberDiff line numberDiff line change
@@ -26,6 +26,7 @@ extern void ProcArrayRemove(PGPROC *proc, TransactionId latestXid);
2626
externvoidProcArrayEndTransaction(PGPROC*proc,TransactionIdlatestXid);
2727
externvoidProcArrayClearTransaction(PGPROC*proc);
2828

29+
externvoidProcArrayInitRecovery(TransactionIdinitializedUptoXID);
2930
externvoidProcArrayApplyRecoveryInfo(RunningTransactionsrunning);
3031
externvoidProcArrayApplyXidAssignment(TransactionIdtopxid,
3132
intnsubxids,TransactionId*subxids);

0 commit comments

Comments
 (0)
[8]ページ先頭
©2009-2025 Movatter.jp