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Make use of new error context stack mechanism to allow random errors
detected during buffer dump to be labeled with the buffer location. For example, if a page LSN is clobbered, we now produce something like ERROR: XLogFlush: request 2C000000/8468EC8 is not satisfied --- flushed only to 0/8468EF0 CONTEXT: writing block 0 of relation 428946/566240 whereas before there was no convenient way to find out which page had been trashed.
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‎src/backend/storage/buffer/bufmgr.c

Lines changed: 64 additions & 6 deletions
Original file line numberDiff line numberDiff line change
@@ -8,7 +8,7 @@
88
*
99
*
1010
* IDENTIFICATION
11-
* $Header: /cvsroot/pgsql/src/backend/storage/buffer/bufmgr.c,v 1.135 2003/03/28 20:17:13 tgl Exp $
11+
* $Header: /cvsroot/pgsql/src/backend/storage/buffer/bufmgr.c,v 1.136 2003/05/10 19:04:30 tgl Exp $
1212
*
1313
*-------------------------------------------------------------------------
1414
*/
@@ -68,6 +68,7 @@ static void WaitIO(BufferDesc *buf);
6868
static void StartBufferIO(BufferDesc *buf, bool forInput);
6969
static void TerminateBufferIO(BufferDesc *buf);
7070
static void ContinueBufferIO(BufferDesc *buf, bool forInput);
71+
static void buffer_write_error_callback(void *arg);
7172

7273
/*
7374
* Macro : BUFFER_IS_BROKEN
@@ -699,14 +700,24 @@ BufferSync(void)
699700
{
700701
int i;
701702
BufferDesc *bufHdr;
702-
Buffer buffer;
703-
int status;
704-
RelFileNode rnode;
705-
XLogRecPtr recptr;
706-
Relation reln = NULL;
703+
ErrorContextCallback errcontext;
704+
705+
/* Setup error traceback support for ereport() */
706+
errcontext.callback = buffer_write_error_callback;
707+
errcontext.arg = NULL;
708+
errcontext.previous = error_context_stack;
709+
error_context_stack = &errcontext;
707710

708711
for (i = 0, bufHdr = BufferDescriptors; i < NBuffers; i++, bufHdr++)
709712
{
713+
Buffer buffer;
714+
int status;
715+
RelFileNode rnode;
716+
XLogRecPtr recptr;
717+
Relation reln;
718+
719+
errcontext.arg = bufHdr;
720+
710721
LWLockAcquire(BufMgrLock, LW_EXCLUSIVE);
711722

712723
if (!(bufHdr->flags & BM_VALID))
@@ -834,6 +845,8 @@ BufferSync(void)
834845
RelationDecrementReferenceCount(reln);
835846
}
836847

848+
/* Pop the error context stack */
849+
error_context_stack = errcontext.previous;
837850
}
838851

839852
/*
@@ -1011,12 +1024,19 @@ BufferReplace(BufferDesc *bufHdr)
10111024
Relation reln;
10121025
XLogRecPtr recptr;
10131026
int status;
1027+
ErrorContextCallback errcontext;
10141028

10151029
/* To check if block content changed while flushing. - vadim 01/17/97 */
10161030
bufHdr->flags &= ~BM_JUST_DIRTIED;
10171031

10181032
LWLockRelease(BufMgrLock);
10191033

1034+
/* Setup error traceback support for ereport() */
1035+
errcontext.callback = buffer_write_error_callback;
1036+
errcontext.arg = bufHdr;
1037+
errcontext.previous = error_context_stack;
1038+
error_context_stack = &errcontext;
1039+
10201040
/*
10211041
* No need to lock buffer context - no one should be able to end
10221042
* ReadBuffer
@@ -1043,6 +1063,9 @@ BufferReplace(BufferDesc *bufHdr)
10431063
if (reln != (Relation) NULL)
10441064
RelationDecrementReferenceCount(reln);
10451065

1066+
/* Pop the error context stack */
1067+
error_context_stack = errcontext.previous;
1068+
10461069
LWLockAcquire(BufMgrLock, LW_EXCLUSIVE);
10471070

10481071
if (status == SM_FAIL)
@@ -1380,12 +1403,20 @@ FlushRelationBuffers(Relation rel, BlockNumber firstDelBlock)
13801403
BufferDesc *bufHdr;
13811404
XLogRecPtr recptr;
13821405
int status;
1406+
ErrorContextCallback errcontext;
1407+
1408+
/* Setup error traceback support for ereport() */
1409+
errcontext.callback = buffer_write_error_callback;
1410+
errcontext.arg = NULL;
1411+
errcontext.previous = error_context_stack;
1412+
error_context_stack = &errcontext;
13831413

13841414
if (rel->rd_istemp)
13851415
{
13861416
for (i = 0; i < NLocBuffer; i++)
13871417
{
13881418
bufHdr = &LocalBufferDescriptors[i];
1419+
errcontext.arg = bufHdr;
13891420
if (RelFileNodeEquals(bufHdr->tag.rnode, rel->rd_node))
13901421
{
13911422
if (bufHdr->flags & BM_DIRTY || bufHdr->cntxDirty)
@@ -1395,6 +1426,7 @@ FlushRelationBuffers(Relation rel, BlockNumber firstDelBlock)
13951426
(char *) MAKE_PTR(bufHdr->data));
13961427
if (status == SM_FAIL)
13971428
{
1429+
error_context_stack = errcontext.previous;
13981430
elog(WARNING, "FlushRelationBuffers(%s (local), %u): block %u is dirty, could not flush it",
13991431
RelationGetRelationName(rel), firstDelBlock,
14001432
bufHdr->tag.blockNum);
@@ -1405,6 +1437,7 @@ FlushRelationBuffers(Relation rel, BlockNumber firstDelBlock)
14051437
}
14061438
if (LocalRefCount[i] > 0)
14071439
{
1440+
error_context_stack = errcontext.previous;
14081441
elog(WARNING, "FlushRelationBuffers(%s (local), %u): block %u is referenced (%ld)",
14091442
RelationGetRelationName(rel), firstDelBlock,
14101443
bufHdr->tag.blockNum, LocalRefCount[i]);
@@ -1414,6 +1447,10 @@ FlushRelationBuffers(Relation rel, BlockNumber firstDelBlock)
14141447
bufHdr->tag.rnode.relNode = InvalidOid;
14151448
}
14161449
}
1450+
1451+
/* Pop the error context stack */
1452+
error_context_stack = errcontext.previous;
1453+
14171454
return 0;
14181455
}
14191456

@@ -1422,6 +1459,7 @@ FlushRelationBuffers(Relation rel, BlockNumber firstDelBlock)
14221459
for (i = 0; i < NBuffers; i++)
14231460
{
14241461
bufHdr = &BufferDescriptors[i];
1462+
errcontext.arg = bufHdr;
14251463
if (RelFileNodeEquals(bufHdr->tag.rnode, rel->rd_node))
14261464
{
14271465
if (bufHdr->flags & BM_DIRTY || bufHdr->cntxDirty)
@@ -1483,6 +1521,7 @@ FlushRelationBuffers(Relation rel, BlockNumber firstDelBlock)
14831521
if (!(bufHdr->flags & BM_FREE))
14841522
{
14851523
LWLockRelease(BufMgrLock);
1524+
error_context_stack = errcontext.previous;
14861525
elog(WARNING, "FlushRelationBuffers(%s, %u): block %u is referenced (private %ld, global %d)",
14871526
RelationGetRelationName(rel), firstDelBlock,
14881527
bufHdr->tag.blockNum,
@@ -1493,7 +1532,12 @@ FlushRelationBuffers(Relation rel, BlockNumber firstDelBlock)
14931532
BufTableDelete(bufHdr);
14941533
}
14951534
}
1535+
14961536
LWLockRelease(BufMgrLock);
1537+
1538+
/* Pop the error context stack */
1539+
error_context_stack = errcontext.previous;
1540+
14971541
return 0;
14981542
}
14991543

@@ -2083,3 +2127,17 @@ BufferGetFileNode(Buffer buffer)
20832127

20842128
return (bufHdr->tag.rnode);
20852129
}
2130+
2131+
/*
2132+
* Error context callback for errors occurring during buffer writes.
2133+
*/
2134+
static void
2135+
buffer_write_error_callback(void *arg)
2136+
{
2137+
BufferDesc *bufHdr = (BufferDesc *) arg;
2138+
2139+
if (bufHdr != NULL)
2140+
errcontext("writing block %u of relation %u/%u",
2141+
bufHdr->tag.blockNum,
2142+
bufHdr->tag.rnode.tblNode, bufHdr->tag.rnode.relNode);
2143+
}

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