8000 Back-patch change to not keep WAL segments just for UNDO information. · jaylevitt/postgres@ef20c69 · GitHub
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Back-patch change to not keep WAL segments just for UNDO information.
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1 file changed

+38
-5
lines changed
  • src/backend/access/transam

1 file changed

+38
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‎src/backend/access/transam/xlog.c

Lines changed: 38 additions & 5 deletions
Original file line numberDiff line numberDiff line change
@@ -7,7 +7,7 @@
77
* Portions Copyright (c) 1996-2001, PostgreSQL Global Development Group
88
* Portions Copyright (c) 1994, Regents of the University of California
99
*
10-
* $Header: /cvsroot/pgsql/src/backend/access/transam/xlog.c,v 1.65 2001/04/05 16:55:21 tgl Exp $
10+
* $Header: /cvsroot/pgsql/src/backend/access/transam/xlog.c,v 1.65.2.1 2001/06/06 17:18:56 tgl Exp $
1111
*
1212
*-------------------------------------------------------------------------
1313
*/
@@ -1068,9 +1068,15 @@ XLogWrite(XLogwrtRqst WriteRqst)
10681068

10691069
/* OK to write the page */
10701070
from = XLogCtl->pages + Write->curridx * BLCKSZ;
1071+
errno = 0;
10711072
if (write(openLogFile, from, BLCKSZ) != BLCKSZ)
1073+
{
1074+
/* if write didn't set errno, assume problem is no disk space */
1075+
if (errno == 0)
1076+
errno = ENOSPC;
10721077
elog(STOP, "write(logfile %u seg %u off %u) failed: %m",
10731078
openLogId, openLogSeg, openLogOff);
1079+
}
10741080
openLogOff += BLCKSZ;
10751081

10761082
/*
@@ -1323,6 +1329,7 @@ XLogFileInit(uint32 log, uint32 seg,
13231329
MemSet(zbuffer, 0, sizeof(zbuffer));
13241330
for (nbytes = 0; nbytes < XLogSegSize; nbytes += sizeof(zbuffer))
13251331
{
1332+
errno = 0;
13261333
if ((int) write(fd, zbuffer, sizeof(zbuffer)) != (int) sizeof(zbuffer))
13271334
{
13281335
int save_errno = errno;
@@ -1332,7 +1339,8 @@ XLogFileInit(uint32 log, uint32 seg,
13321339
* space
13331340
*/
13341341
unlink(tmppath);
1335-
errno = save_errno;
1342+
/* if write didn't set errno, assume problem is no disk space */
1343+
errno = save_errno ? save_errno : ENOSPC;
13361344

13371345
elog(STOP, "ZeroFill(%s) failed: %m", tmppath);
13381346
}
@@ -1987,8 +1995,14 @@ WriteControlFile(void)
19871995
elog(STOP, "WriteControlFile failed to create control file (%s): %m",
19881996
ControlFilePath);
19891997

1998+
errno = 0;
19901999
if (write(fd, buffer, BLCKSZ) != BLCKSZ)
2000+
{
2001+
/* if write didn't set errno, assume problem is no disk space */
2002+
if (errno == 0)
2003+
errno = ENOSPC;
19912004
elog(STOP, "WriteControlFile failed to write control file: %m");
2005+
}
19922006

19932007
if (pg_fsync(fd) != 0)
19942008
elog(STOP, "WriteControlFile failed to fsync control file: %m");
@@ -2085,8 +2099,14 @@ UpdateControlFile(void)
20852099
if (fd < 0)
20862100
elog(STOP, "open(\"%s\") failed: %m", ControlFilePath);
20872101

2102+
errno = 0;
20882103
if (write(fd, ControlFile, sizeof(ControlFileData)) != sizeof(ControlFileData))
2104+
{
2105+
/* if write didn't set errno, assume problem is no disk space */
2106+
if (errno == 0)
2107+
errno = ENOSPC;
20892108
elog(STOP, "write(cntlfile) failed: %m");
2109+
}
20902110

20912111
if (pg_fsync(fd) != 0)
20922112
elog(STOP, "fsync(cntlfile) failed: %m");
@@ -2224,8 +2244,14 @@ BootStrapXLOG(void)
22242244
use_existent = false;
22252245
openLogFile = XLogFileInit(0, 0, &use_existent, false);
22262246

2247+
errno = 0;
22272248
if (write(openLogFile, buffer, BLCKSZ) != BLCKSZ)
2249+
{
2250+
/* if write didn't set errno, assume problem is no disk space */
2251+
if (errno == 0)
2252+
errno = ENOSPC;
22282253
elog(STOP, "BootStrapXLOG failed to write logfile: %m");
2254+
}
22292255

22302256
if (pg_fsync(openLogFile) != 0)
22312257
elog(STOP, "BootStrapXLOG failed to fsync logfile: %m");
@@ -2816,15 +2842,22 @@ CreateCheckPoint(bool shutdown)
28162842
elog(STOP, "XLog concurrent activity while data base is shutting down");
28172843

28182844
/*
2819-
* Remember location of prior checkpoint's earliest info. Oldest item
2820-
* is redo or undo, whichever is older; but watch out for case that
2821-
* undo = 0.
2845+
* Select point at which we can truncate the log, which we base on the
2846+
* prior checkpoint's earliest info.
2847+
*
2848+
* With UNDO support: oldest item is redo or undo, whichever is older;
2849+
* but watch out for case that undo = 0.
2850+
*
2851+
* Without UNDO support: just use the redo pointer. This allows xlog
2852+
* space to be freed much faster when there are long-running transactions.
28222853
*/
2854+
#ifdef NOT_USED
28232855
if (ControlFile->checkPointCopy.undo.xrecoff != 0 &&
28242856
XLByteLT(ControlFile->checkPointCopy.undo,
28252857
ControlFile->checkPointCopy.redo))
28262858
XLByteToSeg(ControlFile->checkPointCopy.undo, _logId, _logSeg);
28272859
else
2860+
#endif
28282861
XLByteToSeg(ControlFile->checkPointCopy.redo, _logId, _logSeg);
28292862

28302863
/*

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