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Restructure backend SIGINT/SIGTERM handling so that 'die' interrupts
are treated more like 'cancel' interrupts: the signal handler sets a flag that is examined at well-defined spots, rather than trying to cope with an interrupt that might happen anywhere. See pghackers discussion of 1/12/01.
1 parent 027f144 commit 36839c1

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24 files changed

+615
-480
lines changed

24 files changed

+615
-480
lines changed

‎src/backend/access/nbtree/nbtinsert.c

Lines changed: 2 additions & 1 deletion
Original file line numberDiff line numberDiff line change
@@ -8,7 +8,7 @@
88
*
99
*
1010
* IDENTIFICATION
11-
* $Header: /cvsroot/pgsql/src/backend/access/nbtree/nbtinsert.c,v 1.73 2001/01/12 21:53:55 tgl Exp $
11+
* $Header: /cvsroot/pgsql/src/backend/access/nbtree/nbtinsert.c,v 1.74 2001/01/14 05:08:14 tgl Exp $
1212
*
1313
*-------------------------------------------------------------------------
1414
*/
@@ -17,6 +17,7 @@
1717

1818
#include "access/heapam.h"
1919
#include "access/nbtree.h"
20+
#include "miscadmin.h"
2021

2122

2223
typedef struct

‎src/backend/access/transam/xact.c

Lines changed: 18 additions & 1 deletion
Original file line numberDiff line numberDiff line change
@@ -8,7 +8,7 @@
88
*
99
*
1010
* IDENTIFICATION
11-
* $Header: /cvsroot/pgsql/src/backend/access/transam/xact.c,v 1.92 2001/01/12 21:53:56 tgl Exp $
11+
* $Header: /cvsroot/pgsql/src/backend/access/transam/xact.c,v 1.93 2001/01/14 05:08:14 tgl Exp $
1212
*
1313
* NOTES
1414
* Transaction aborts can now occur two ways:
@@ -1015,6 +1015,9 @@ CommitTransaction(void)
10151015
if (s->state != TRANS_INPROGRESS)
10161016
elog(NOTICE, "CommitTransaction and not in in-progress state ");
10171017

1018+
/* Prevent cancel/die interrupt while cleaning up */
1019+
START_CRIT_SECTION();
1020+
10181021
/* ----------------
10191022
* Tell the trigger manager that this transaction is about to be
10201023
* committed. He'll invoke all trigger deferred until XACT before
@@ -1083,6 +1086,8 @@ CommitTransaction(void)
10831086
* ----------------
10841087
*/
10851088
s->state = TRANS_DEFAULT;
1089+
1090+
END_CRIT_SECTION();
10861091
}
10871092

10881093
/* --------------------------------
@@ -1095,6 +1100,9 @@ AbortTransaction(void)
10951100
{
10961101
TransactionState s = CurrentTransactionState;
10971102

1103+
/* Prevent cancel/die interrupt while cleaning up */
1104+
START_CRIT_SECTION();
1105+
10981106
/*
10991107
* Let others to know about no transaction in progress - vadim
11001108
* 11/26/96
@@ -1113,13 +1121,21 @@ AbortTransaction(void)
11131121
*/
11141122
ProcReleaseSpins(NULL);
11151123
UnlockBuffers();
1124+
/*
1125+
* Also clean up any open wait for lock, since the lock manager
1126+
* will choke if we try to wait for another lock before doing this.
1127+
*/
1128+
LockWaitCancel();
11161129

11171130
/* ----------------
11181131
* check the current transaction state
11191132
* ----------------
11201133
*/
11211134
if (s->state == TRANS_DISABLED)
1135+
{
1136+
END_CRIT_SECTION();
11221137
return;
1138+
}
11231139

11241140
if (s->state != TRANS_INPROGRESS)
11251141
elog(NOTICE, "AbortTransaction and not in in-progress state");
@@ -1169,6 +1185,7 @@ AbortTransaction(void)
11691185
* State remains TRANS_ABORT until CleanupTransaction().
11701186
* ----------------
11711187
*/
1188+
END_CRIT_SECTION();
11721189
}
11731190

11741191
/* --------------------------------

‎src/backend/access/transam/xlog.c

Lines changed: 1 addition & 2 deletions
Original file line numberDiff line numberDiff line change
@@ -6,7 +6,7 @@
66
* Portions Copyright (c) 1996-2000, PostgreSQL, Inc
77
* Portions Copyright (c) 1994, Regents of the University of California
88
*
9-
* $Header: /cvsroot/pgsql/src/backend/access/transam/xlog.c,v 1.49 2001/01/12 21:53:56 tgl Exp $
9+
* $Header: /cvsroot/pgsql/src/backend/access/transam/xlog.c,v 1.50 2001/01/14 05:08:15 tgl Exp $
1010
*
1111
*-------------------------------------------------------------------------
1212
*/
@@ -42,7 +42,6 @@
4242
int XLOGbuffers = 8;
4343
int XLOGfiles = 0; /* how many files to pre-allocate */
4444
XLogRecPtr MyLastRecPtr = {0, 0};
45-
volatile uint32 CritSectionCount = 0;
4645
bool InRecovery = false;
4746
StartUpID ThisStartUpID = 0;
4847
XLogRecPtr RedoRecPtr;

‎src/backend/bootstrap/bootstrap.c

Lines changed: 5 additions & 6 deletions
Original file line numberDiff line numberDiff line change
@@ -8,7 +8,7 @@
88
* Portions Copyright (c) 1994, Regents of the University of California
99
*
1010
* IDENTIFICATION
11-
* $Header: /cvsroot/pgsql/src/backend/bootstrap/bootstrap.c,v 1.102 2000/12/28 13:00:12 vadim Exp $
11+
* $Header: /cvsroot/pgsql/src/backend/bootstrap/bootstrap.c,v 1.103 2001/01/14 05:08:15 tgl Exp $
1212
*
1313
*-------------------------------------------------------------------------
1414
*/
@@ -329,9 +329,10 @@ BootstrapMain(int argc, char *argv[])
329329

330330
if (!IsUnderPostmaster)
331331
{
332-
pqsignal(SIGINT, (pqsigfunc) die);
333-
pqsignal(SIGHUP, (pqsigfunc) die);
334-
pqsignal(SIGTERM, (pqsigfunc) die);
332+
pqsignal(SIGHUP, die);
333+
pqsignal(SIGINT, die);
334+
pqsignal(SIGTERM, die);
335+
pqsignal(SIGQUIT, die);
335336
}
336337

337338
/*
@@ -383,8 +384,6 @@ BootstrapMain(int argc, char *argv[])
383384
* abort processing resumes here
384385
* ----------------
385386
*/
386-
pqsignal(SIGHUP, handle_warn);
387-
388387
if (sigsetjmp(Warn_restart, 1) != 0)
389388
{
390389
Warnings++;

‎src/backend/commands/analyze.c

Lines changed: 2 additions & 3 deletions
Original file line numberDiff line numberDiff line change
@@ -8,7 +8,7 @@
88
*
99
*
1010
* IDENTIFICATION
11-
* $Header: /cvsroot/pgsql/src/backend/commands/analyze.c,v 1.10 2000/12/02 19:38:34 tgl Exp $
11+
* $Header: /cvsroot/pgsql/src/backend/commands/analyze.c,v 1.11 2001/01/14 05:08:15 tgl Exp $
1212
*
1313
*-------------------------------------------------------------------------
1414
*/
@@ -72,8 +72,7 @@ analyze_rel(Oid relid, List *anal_cols2, int MESSAGE_LEVEL)
7272
* Check for user-requested abort. Note we want this to be inside a
7373
* transaction, so xact.c doesn't issue useless NOTICE.
7474
*/
75-
if (QueryCancel)
76-
CancelQuery();
75+
CHECK_FOR_INTERRUPTS();
7776

7877
/*
7978
* Race condition -- if the pg_class tuple has gone away since the

‎src/backend/commands/copy.c

Lines changed: 3 additions & 8 deletions
Original file line numberDiff line numberDiff line change
@@ -7,7 +7,7 @@
77
*
88
*
99
* IDENTIFICATION
10-
* $Header: /cvsroot/pgsql/src/backend/commands/copy.c,v 1.128 2001/01/06 03:33:17 ishii Exp $
10+
* $Header: /cvsroot/pgsql/src/backend/commands/copy.c,v 1.129 2001/01/14 05:08:15 tgl Exp $
1111
*
1212
*-------------------------------------------------------------------------
1313
*/
@@ -449,8 +449,7 @@ CopyTo(Relation rel, bool binary, bool oids, FILE *fp,
449449
{
450450
bool need_delim = false;
451451

452-
if (QueryCancel)
453-
CancelQuery();
452+
CHECK_FOR_INTERRUPTS();
454453

455454
if (binary)
456455
{
@@ -702,11 +701,7 @@ CopyFrom(Relation rel, bool binary, bool oids, FILE *fp,
702701

703702
while (!done)
704703
{
705-
if (QueryCancel)
706-
{
707-
lineno = 0;
708-
CancelQuery();
709-
}
704+
CHECK_FOR_INTERRUPTS();
710705

711706
lineno++;
712707

‎src/backend/commands/vacuum.c

Lines changed: 2 additions & 3 deletions
Original file line numberDiff line numberDiff line change
@@ -8,7 +8,7 @@
88
*
99
*
1010
* IDENTIFICATION
11-
* $Header: /cvsroot/pgsql/src/backend/commands/vacuum.c,v 1.182 2001/01/12 21:53:56 tgl Exp $
11+
* $Header: /cvsroot/pgsql/src/backend/commands/vacuum.c,v 1.183 2001/01/14 05:08:15 tgl Exp $
1212
*
1313
*-------------------------------------------------------------------------
1414
*/
@@ -378,8 +378,7 @@ vacuum_rel(Oid relid)
378378
* Check for user-requested abort. Note we want this to be inside a
379379
* transaction, so xact.c doesn't issue useless NOTICE.
380380
*/
381-
if (QueryCancel)
382-
CancelQuery();
381+
CHECK_FOR_INTERRUPTS();
383382

384383
/*
385384
* Race condition -- if the pg_class tuple has gone away since the

‎src/backend/executor/execProcnode.c

Lines changed: 3 additions & 5 deletions
Original file line numberDiff line numberDiff line change
@@ -12,7 +12,7 @@
1212
*
1313
*
1414
* IDENTIFICATION
15-
* $Header: /cvsroot/pgsql/src/backend/executor/execProcnode.c,v 1.22 2000/10/26 21:35:15 tgl Exp $
15+
* $Header: /cvsroot/pgsql/src/backend/executor/execProcnode.c,v 1.23 2001/01/14 05:08:15 tgl Exp $
1616
*
1717
*-------------------------------------------------------------------------
1818
*/
@@ -248,14 +248,12 @@ ExecProcNode(Plan *node, Plan *parent)
248248
{
249249
TupleTableSlot *result;
250250

251+
CHECK_FOR_INTERRUPTS();
252+
251253
/* ----------------
252254
* deal with NULL nodes..
253255
* ----------------
254256
*/
255-
256-
if (QueryCancel)
257-
CancelQuery();
258-
259257
if (node == NULL)
260258
return NULL;
261259

‎src/backend/storage/buffer/bufmgr.c

Lines changed: 59 additions & 14 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 1.103 2001/01/12 21:53:57 tgl Exp $
11+
* $Header: /cvsroot/pgsql/src/backend/storage/buffer/bufmgr.c,v 1.104 2001/01/14 05:08:15 tgl Exp $
1212
*
1313
*-------------------------------------------------------------------------
1414
*/
@@ -92,6 +92,7 @@ static Buffer ReadBufferWithBufferLock(Relation relation, BlockNumber blockNum,
9292
bool bufferLockHeld);
9393
static BufferDesc *BufferAlloc(Relation reln, BlockNumber blockNum,
9494
bool *foundPtr, bool bufferLockHeld);
95+
static int ReleaseBufferWithBufferLock(Buffer buffer);
9596
static int BufferReplace(BufferDesc *bufHdr);
9697
void PrintBufferDescs(void);
9798

@@ -687,10 +688,14 @@ ReleaseAndReadBuffer(Buffer buffer,
687688
{
688689
bufHdr = &BufferDescriptors[buffer - 1];
689690
Assert(PrivateRefCount[buffer - 1] > 0);
690-
PrivateRefCount[buffer - 1]--;
691-
if (PrivateRefCount[buffer - 1] == 0)
691+
if (PrivateRefCount[buffer - 1] > 1)
692+
{
693+
PrivateRefCount[buffer - 1]--;
694+
}
695+
else
692696
{
693697
SpinAcquire(BufMgrLock);
698+
PrivateRefCount[buffer - 1] = 0;
694699
Assert(bufHdr->refcount > 0);
695700
bufHdr->refcount--;
696701
if (bufHdr->refcount == 0)
@@ -1185,10 +1190,7 @@ DropRelationBuffers(Relation rel)
11851190
/* Assert checks that buffer will actually get freed! */
11861191
Assert(PrivateRefCount[i - 1] == 1 &&
11871192
bufHdr->refcount == 1);
1188-
/* ReleaseBuffer expects we do not hold the lock at entry */
1189-
SpinRelease(BufMgrLock);
1190-
ReleaseBuffer(i);
1191-
SpinAcquire(BufMgrLock);
1193+
ReleaseBufferWithBufferLock(i);
11921194
}
11931195
/*
11941196
* And mark the buffer as no longer occupied by this rel.
@@ -1270,10 +1272,7 @@ DropRelFileNodeBuffers(RelFileNode rnode)
12701272
/* Assert checks that buffer will actually get freed! */
12711273
Assert(PrivateRefCount[i - 1] == 1 &&
12721274
bufHdr->refcount == 1);
1273-
/* ReleaseBuffer expects we do not hold the lock at entry */
1274-
SpinRelease(BufMgrLock);
1275-
ReleaseBuffer(i);
1276-
SpinAcquire(BufMgrLock);
1275+
ReleaseBufferWithBufferLock(i);
12771276
}
12781277
/*
12791278
* And mark the buffer as no longer occupied by this rel.
@@ -1624,10 +1623,14 @@ ReleaseBuffer(Buffer buffer)
16241623
bufHdr = &BufferDescriptors[buffer - 1];
16251624

16261625
Assert(PrivateRefCount[buffer - 1] > 0);
1627-
PrivateRefCount[buffer - 1]--;
1628-
if (PrivateRefCount[buffer - 1] == 0)
1626+
if (PrivateRefCount[buffer - 1] > 1)
1627+
{
1628+
PrivateRefCount[buffer - 1]--;
1629+
}
1630+
else
16291631
{
16301632
SpinAcquire(BufMgrLock);
1633+
PrivateRefCount[buffer - 1] = 0;
16311634
Assert(bufHdr->refcount > 0);
16321635
bufHdr->refcount--;
16331636
if (bufHdr->refcount == 0)
@@ -1641,6 +1644,48 @@ ReleaseBuffer(Buffer buffer)
16411644
return STATUS_OK;
16421645
}
16431646

1647+
/*
1648+
* ReleaseBufferWithBufferLock
1649+
* Same as ReleaseBuffer except we hold the lock
1650+
*/
1651+
static int
1652+
ReleaseBufferWithBufferLock(Buffer buffer)
1653+
{
1654+
BufferDesc *bufHdr;
1655+
1656+
if (BufferIsLocal(buffer))
1657+
{
1658+
Assert(LocalRefCount[-buffer - 1] > 0);
1659+
LocalRefCount[-buffer - 1]--;
1660+
return STATUS_OK;
1661+
}
1662+
1663+
if (BAD_BUFFER_ID(buffer))
1664+
return STATUS_ERROR;
1665+
1666+
bufHdr = &BufferDescriptors[buffer - 1];
1667+
1668+
Assert(PrivateRefCount[buffer - 1] > 0);
1669+
if (PrivateRefCount[buffer - 1] > 1)
1670+
{
1671+
PrivateRefCount[buffer - 1]--;
1672+
}
1673+
else
1674+
{
1675+
PrivateRefCount[buffer - 1] = 0;
1676+
Assert(bufHdr->refcount > 0);
1677+
bufHdr->refcount--;
1678+
if (bufHdr->refcount == 0)
1679+
{
1680+
AddBufferToFreelist(bufHdr);
1681+
bufHdr->flags |= BM_FREE;
1682+
}
1683+
}
1684+
1685+
return STATUS_OK;
1686+
}
1687+
1688+
16441689
#ifdef NOT_USED
16451690
void
16461691
IncrBufferRefCount_Debug(char *file, int line, Buffer buffer)
@@ -2217,9 +2262,9 @@ MarkBufferForCleanup(Buffer buffer, void (*CleanupFunc)(Buffer))
22172262
SpinRelease(BufMgrLock);
22182263

22192264
LockBuffer(buffer, BUFFER_LOCK_UNLOCK);
2220-
PrivateRefCount[buffer - 1]--;
22212265

22222266
SpinAcquire(BufMgrLock);
2267+
PrivateRefCount[buffer - 1] = 0;
22232268
Assert(bufHdr->refcount > 0);
22242269
bufHdr->flags |= (BM_DIRTY | BM_JUST_DIRTIED);
22252270
bufHdr->CleanupFunc = CleanupFunc;

‎src/backend/storage/buffer/s_lock.c

Lines changed: 8 additions & 1 deletion
Original file line numberDiff line numberDiff line change
@@ -8,7 +8,7 @@
88
*
99
*
1010
* IDENTIFICATION
11-
* $Header: /cvsroot/pgsql/src/backend/storage/buffer/Attic/s_lock.c,v 1.28 2000/12/29 21:31:20 tgl Exp $
11+
* $Header: /cvsroot/pgsql/src/backend/storage/buffer/Attic/s_lock.c,v 1.29 2001/01/14 05:08:15 tgl Exp $
1212
*
1313
*-------------------------------------------------------------------------
1414
*/
@@ -17,6 +17,7 @@
1717
#include <sys/time.h>
1818
#include <unistd.h>
1919

20+
#include "miscadmin.h"
2021
#include "storage/s_lock.h"
2122

2223

@@ -101,10 +102,16 @@ s_lock(volatile slock_t *lock, const char *file, const int line)
101102
/*
102103
* If you are thinking of changing this code, be careful. This same
103104
* loop logic is used in other places that call TAS() directly.
105+
*
106+
* While waiting for a lock, we check for cancel/die interrupts (which
107+
* is a no-op if we are inside a critical section). The interrupt check
108+
* can be omitted in places that know they are inside a critical section.
109+
* Note that an interrupt must NOT be accepted after acquiring the lock.
104110
*/
105111
while (TAS(lock))
106112
{
107113
s_lock_sleep(spins++, 0, lock, file, line);
114+
CHECK_FOR_INTERRUPTS();
108115
}
109116
}
110117

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