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Write a WAL record whenever we perform an operation without WAL-logging
that would've been WAL-logged if archiving was enabled. If we encounter such records in archive recovery anyway, we know that some data is missing from the log. A WARNING is emitted in that case. Original patch by Fujii Masao, with changes by me.
1 parent 47ce95a commit 09b115f

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7 files changed

+100
-7
lines changed

7 files changed

+100
-7
lines changed

‎src/backend/access/heap/heapam.c

Lines changed: 7 additions & 1 deletion
Original file line numberDiff line numberDiff line change
@@ -8,7 +8,7 @@
88
*
99
*
1010
* IDENTIFICATION
11-
* $PostgreSQL: pgsql/src/backend/access/heap/heapam.c,v 1.282 2010/01/14 11:08:00 sriggs Exp $
11+
* $PostgreSQL: pgsql/src/backend/access/heap/heapam.c,v 1.283 2010/01/20 19:43:40 heikki Exp $
1212
*
1313
*
1414
* INTERFACE ROUTINES
@@ -5074,10 +5074,16 @@ heap2_desc(StringInfo buf, uint8 xl_info, char *rec)
50745074
void
50755075
heap_sync(Relation rel)
50765076
{
5077+
char reason[NAMEDATALEN + 30];
5078+
50775079
/* temp tables never need fsync */
50785080
if (rel->rd_istemp)
50795081
return;
50805082

5083+
snprintf(reason, sizeof(reason), "heap inserts on \"%s\"",
5084+
RelationGetRelationName(rel));
5085+
XLogReportUnloggedStatement(reason);
5086+
50815087
/* main heap */
50825088
FlushRelationBuffers(rel);
50835089
/* FlushRelationBuffers will have opened rd_smgr */

‎src/backend/access/nbtree/nbtsort.c

Lines changed: 13 additions & 1 deletion
Original file line numberDiff line numberDiff line change
@@ -59,7 +59,7 @@
5959
* Portions Copyright (c) 1994, Regents of the University of California
6060
*
6161
* IDENTIFICATION
62-
* $PostgreSQL: pgsql/src/backend/access/nbtree/nbtsort.c,v 1.122 2010/01/15 09:19:00 heikki Exp $
62+
* $PostgreSQL: pgsql/src/backend/access/nbtree/nbtsort.c,v 1.123 2010/01/20 19:43:40 heikki Exp $
6363
*
6464
*-------------------------------------------------------------------------
6565
*/
@@ -215,6 +215,18 @@ _bt_leafbuild(BTSpool *btspool, BTSpool *btspool2)
215215
*/
216216
wstate.btws_use_wal = XLogIsNeeded() && !wstate.index->rd_istemp;
217217

218+
/*
219+
* Write an XLOG UNLOGGED record if WAL-logging was skipped because
220+
* WAL archiving is not enabled.
221+
*/
222+
if (!wstate.btws_use_wal && !wstate.index->rd_istemp)
223+
{
224+
char reason[NAMEDATALEN + 20];
225+
snprintf(reason, sizeof(reason), "b-tree build on \"%s\"",
226+
RelationGetRelationName(wstate.index));
227+
XLogReportUnloggedStatement(reason);
228+
}
229+
218230
/* reserve the metapage */
219231
wstate.btws_pages_alloced = BTREE_METAPAGE + 1;
220232
wstate.btws_pages_written = 0;

‎src/backend/access/transam/xlog.c

Lines changed: 45 additions & 1 deletion
Original file line numberDiff line numberDiff line change
@@ -7,7 +7,7 @@
77
* Portions Copyright (c) 1996-2010, PostgreSQL Global Development Group
88
* Portions Copyright (c) 1994, Regents of the University of California
99
*
10-
* $PostgreSQL: pgsql/src/backend/access/transam/xlog.c,v 1.358 2010/01/15 09:19:00 heikki Exp $
10+
* $PostgreSQL: pgsql/src/backend/access/transam/xlog.c,v 1.359 2010/01/20 19:43:40 heikki Exp $
1111
*
1212
*-------------------------------------------------------------------------
1313
*/
@@ -7561,6 +7561,31 @@ RequestXLogSwitch(void)
75617561
return RecPtr;
75627562
}
75637563

7564+
/*
7565+
* Write an XLOG UNLOGGED record, indicating that some operation was
7566+
* performed on data that we fsync()'d directly to disk, skipping
7567+
* WAL-logging.
7568+
*
7569+
* Such operations screw up archive recovery, so we complain if we see
7570+
* these records during archive recovery. That shouldn't happen in a
7571+
* correctly configured server, but you can induce it by temporarily
7572+
* disabling archiving and restarting, so it's good to at least get a
7573+
* warning of silent data loss in such cases. These records serve no
7574+
* other purpose and are simply ignored during crash recovery.
7575+
*/
7576+
void
7577+
XLogReportUnloggedStatement(char *reason)
7578+
{
7579+
XLogRecData rdata;
7580+
7581+
rdata.buffer = InvalidBuffer;
7582+
rdata.data = reason;
7583+
rdata.len = strlen(reason) + 1;
7584+
rdata.next = NULL;
7585+
7586+
XLogInsert(RM_XLOG_ID, XLOG_UNLOGGED, &rdata);
7587+
}
7588+
75647589
/*
75657590
* XLOG resource manager's routines
75667591
*
@@ -7703,6 +7728,19 @@ xlog_redo(XLogRecPtr lsn, XLogRecord *record)
77037728
LWLockRelease(ControlFileLock);
77047729
}
77057730
}
7731+
else if (info == XLOG_UNLOGGED)
7732+
{
7733+
if (InArchiveRecovery)
7734+
{
7735+
/*
7736+
* Note: We don't print the reason string from the record,
7737+
* because that gets added as a line using xlog_desc()
7738+
*/
7739+
ereport(WARNING,
7740+
(errmsg("unlogged operation performed, data may be missing"),
7741+
errhint("This can happen if you temporarily disable archive_mode without taking a new base backup.")));
7742+
}
7743+
}
77067744
}
77077745

77087746
void
@@ -7752,6 +7790,12 @@ xlog_desc(StringInfo buf, uint8 xl_info, char *rec)
77527790
appendStringInfo(buf, "backup end: %X/%X",
77537791
startpoint.xlogid, startpoint.xrecoff);
77547792
}
7793+
else if (info == XLOG_UNLOGGED)
7794+
{
7795+
char *reason = rec;
7796+
7797+
appendStringInfo(buf, "unlogged operation: %s", reason);
7798+
}
77557799
else
77567800
appendStringInfo(buf, "UNKNOWN");
77577801
}

‎src/backend/commands/cluster.c

Lines changed: 13 additions & 1 deletion
Original file line numberDiff line numberDiff line change
@@ -11,7 +11,7 @@
1111
*
1212
*
1313
* IDENTIFICATION
14-
* $PostgreSQL: pgsql/src/backend/commands/cluster.c,v 1.193 2010/01/15 09:19:01 heikki Exp $
14+
* $PostgreSQL: pgsql/src/backend/commands/cluster.c,v 1.194 2010/01/20 19:43:40 heikki Exp $
1515
*
1616
*-------------------------------------------------------------------------
1717
*/
@@ -821,6 +821,18 @@ copy_heap_data(Oid OIDNewHeap, Oid OIDOldHeap, Oid OIDOldIndex,
821821
*/
822822
use_wal = XLogIsNeeded() && !NewHeap->rd_istemp;
823823

824+
/*
825+
* Write an XLOG UNLOGGED record if WAL-logging was skipped because
826+
* WAL archiving is not enabled.
827+
*/
828+
if (!use_wal && !NewHeap->rd_istemp)
829+
{
830+
char reason[NAMEDATALEN + 20];
831+
snprintf(reason, sizeof(reason), "CLUSTER on \"%s\"",
832+
RelationGetRelationName(NewHeap));
833+
XLogReportUnloggedStatement(reason);
834+
}
835+
824836
/* use_wal off requires rd_targblock be initially invalid */
825837
Assert(NewHeap->rd_targblock == InvalidBlockNumber);
826838

‎src/backend/commands/tablecmds.c

Lines changed: 18 additions & 1 deletion
Original file line numberDiff line numberDiff line change
@@ -8,7 +8,7 @@
88
*
99
*
1010
* IDENTIFICATION
11-
* $PostgreSQL: pgsql/src/backend/commands/tablecmds.c,v 1.316 2010/01/17 22:56:21 tgl Exp $
11+
* $PostgreSQL: pgsql/src/backend/commands/tablecmds.c,v 1.317 2010/01/20 19:43:40 heikki Exp $
1212
*
1313
*-------------------------------------------------------------------------
1414
*/
@@ -7015,6 +7015,19 @@ ATExecSetTableSpace(Oid tableOid, Oid newTableSpace)
70157015

70167016
heap_close(pg_class, RowExclusiveLock);
70177017

7018+
/*
7019+
* Write an XLOG UNLOGGED record if WAL-logging was skipped because
7020+
* WAL archiving is not enabled.
7021+
*/
7022+
if (!XLogIsNeeded() && !rel->rd_istemp)
7023+
{
7024+
char reason[NAMEDATALEN + 40];
7025+
snprintf(reason, sizeof(reason), "ALTER TABLE SET TABLESPACE on \"%s\"",
7026+
RelationGetRelationName(rel));
7027+
7028+
XLogReportUnloggedStatement(reason);
7029+
}
7030+
70187031
relation_close(rel, NoLock);
70197032

70207033
/* Make sure the reltablespace change is visible */
@@ -7043,6 +7056,10 @@ copy_relation_data(SMgrRelation src, SMgrRelation dst,
70437056
/*
70447057
* We need to log the copied data in WAL iff WAL archiving/streaming is
70457058
* enabled AND it's not a temp rel.
7059+
*
7060+
* Note: If you change the conditions here, update the conditions in
7061+
* ATExecSetTableSpace() for when an XLOG UNLOGGED record is written
7062+
* to match.
70467063
*/
70477064
use_wal = XLogIsNeeded() && !istemp;
70487065

‎src/include/access/xlog.h

Lines changed: 2 additions & 1 deletion
Original file line numberDiff line numberDiff line change
@@ -6,7 +6,7 @@
66
* Portions Copyright (c) 1996-2010, PostgreSQL Global Development Group
77
* Portions Copyright (c) 1994, Regents of the University of California
88
*
9-
* $PostgreSQL: pgsql/src/include/access/xlog.h,v 1.97 2010/01/16 00:04:41 tgl Exp $
9+
* $PostgreSQL: pgsql/src/include/access/xlog.h,v 1.98 2010/01/20 19:43:40 heikki Exp $
1010
*/
1111
#ifndef XLOG_H
1212
#define XLOG_H
@@ -278,6 +278,7 @@ extern void InitXLOGAccess(void);
278278
extern void CreateCheckPoint(int flags);
279279
extern bool CreateRestartPoint(int flags);
280280
extern void XLogPutNextOid(Oid nextOid);
281+
extern void XLogReportUnloggedStatement(char *reason);
281282
extern XLogRecPtr GetRedoRecPtr(void);
282283
extern XLogRecPtr GetInsertRecPtr(void);
283284
extern XLogRecPtr GetWriteRecPtr(void);

‎src/include/catalog/pg_control.h

Lines changed: 2 additions & 1 deletion
Original file line numberDiff line numberDiff line change
@@ -8,7 +8,7 @@
88
* Portions Copyright (c) 1996-2010, PostgreSQL Global Development Group
99
* Portions Copyright (c) 1994, Regents of the University of California
1010
*
11-
* $PostgreSQL: pgsql/src/include/catalog/pg_control.h,v 1.48 2010/01/04 12:50:50 heikki Exp $
11+
* $PostgreSQL: pgsql/src/include/catalog/pg_control.h,v 1.49 2010/01/20 19:43:40 heikki Exp $
1212
*
1313
*-------------------------------------------------------------------------
1414
*/
@@ -63,6 +63,7 @@ typedef struct CheckPoint
6363
#define XLOG_NEXTOID 0x30
6464
#define XLOG_SWITCH 0x40
6565
#define XLOG_BACKUP_END 0x50
66+
#define XLOG_UNLOGGED 0x60
6667

6768

6869
/* System status indicator */

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