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Support syncing WAL log to disk using either fsync(), fdatasync(),
O_SYNC, or O_DSYNC (as available on a given platform). Add GUC parameter to control sync method. Also, add defense to XLogWrite to prevent it from going nuts if passed a target write position that's past the end of the buffers so far filled by XLogInsert.
This commit is contained in:
Tom Lane
@ -7,7 +7,7 @@
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* Portions Copyright (c) 1996-2001, PostgreSQL Global Development Group
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* Portions Copyright (c) 1994, Regents of the University of California
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*
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* $Header: /cvsroot/pgsql/src/backend/access/transam/xlog.c,v 1.58 2001/03/14 20:23:04 tgl Exp $
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* $Header: /cvsroot/pgsql/src/backend/access/transam/xlog.c,v 1.59 2001/03/16 05:44:33 tgl Exp $
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*
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*-------------------------------------------------------------------------
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*/
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@ -42,6 +42,47 @@
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#include "miscadmin.h"
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/*
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* This chunk of hackery attempts to determine which file sync methods
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* are available on the current platform, and to choose an appropriate
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* default method. We assume that fsync() is always available, and that
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* configure determined whether fdatasync() is.
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*/
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#define SYNC_METHOD_FSYNC 0
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#define SYNC_METHOD_FDATASYNC 1
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#define SYNC_METHOD_OPEN 2 /* used for both O_SYNC and O_DSYNC */
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#if defined(O_SYNC)
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# define OPEN_SYNC_FLAG O_SYNC
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#else
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# if defined(O_FSYNC)
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# define OPEN_SYNC_FLAG O_FSYNC
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# endif
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#endif
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#if defined(OPEN_SYNC_FLAG)
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# if defined(O_DSYNC) && (O_DSYNC != OPEN_SYNC_FLAG)
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# define OPEN_DATASYNC_FLAG O_DSYNC
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# endif
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#endif
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#if defined(OPEN_DATASYNC_FLAG)
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# define DEFAULT_SYNC_METHOD_STR "open_datasync"
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# define DEFAULT_SYNC_METHOD SYNC_METHOD_OPEN
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# define DEFAULT_SYNC_FLAGBIT OPEN_DATASYNC_FLAG
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#else
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# if defined(HAVE_FDATASYNC)
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# define DEFAULT_SYNC_METHOD_STR "fdatasync"
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# define DEFAULT_SYNC_METHOD SYNC_METHOD_FDATASYNC
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# define DEFAULT_SYNC_FLAGBIT 0
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# else
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# define DEFAULT_SYNC_METHOD_STR "fsync"
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# define DEFAULT_SYNC_METHOD SYNC_METHOD_FSYNC
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# define DEFAULT_SYNC_FLAGBIT 0
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# endif
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#endif
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/* Max time to wait to acquire XLog activity locks */
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#define XLOG_LOCK_TIMEOUT (5*60*1000000) /* 5 minutes */
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/* Max time to wait to acquire checkpoint lock */
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@ -52,10 +93,18 @@ int CheckPointSegments = 3;
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int XLOGbuffers = 8;
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int XLOGfiles = 0; /* how many files to pre-allocate during ckpt */
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int XLOG_DEBUG = 0;
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char *XLOG_sync_method = NULL;
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const char XLOG_sync_method_default[] = DEFAULT_SYNC_METHOD_STR;
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char XLOG_archive_dir[MAXPGPATH]; /* null string means delete 'em */
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/* these are derived from XLOG_sync_method by assign_xlog_sync_method */
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static int sync_method = DEFAULT_SYNC_METHOD;
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static int open_sync_bit = DEFAULT_SYNC_FLAGBIT;
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#define MinXLOGbuffers 4
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#define XLOG_SYNC_BIT (enableFsync ? open_sync_bit : 0)
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/*
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* ThisStartUpID will be same in all backends --- it identifies current
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@ -365,6 +414,7 @@ static void WriteControlFile(void);
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static void ReadControlFile(void);
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static char *str_time(time_t tnow);
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static void xlog_outrec(char *buf, XLogRecord *record);
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static void issue_xlog_fsync(void);
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/*
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@ -917,6 +967,15 @@ XLogWrite(XLogwrtRqst WriteRqst)
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while (XLByteLT(LogwrtResult.Write, WriteRqst.Write))
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{
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/*
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* Make sure we're not ahead of the insert process. This could
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* happen if we're passed a bogus WriteRqst.Write that is past the
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* end of the last page that's been initialized by
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* AdvanceXLInsertBuffer.
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*/
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if (!XLByteLT(LogwrtResult.Write, XLogCtl->xlblocks[Write->curridx]))
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elog(STOP, "XLogWrite: write request is past end of log");
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/* Advance LogwrtResult.Write to end of current buffer page */
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LogwrtResult.Write = XLogCtl->xlblocks[Write->curridx];
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ispartialpage = XLByteLT(WriteRqst.Write, LogwrtResult.Write);
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@ -1004,9 +1063,7 @@ XLogWrite(XLogwrtRqst WriteRqst)
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*/
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if (openLogOff >= XLogSegSize && !ispartialpage)
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{
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if (pg_fdatasync(openLogFile) != 0)
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elog(STOP, "fsync(logfile %u seg %u) failed: %m",
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openLogId, openLogSeg);
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issue_xlog_fsync();
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LogwrtResult.Flush = LogwrtResult.Write; /* end of current page */
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}
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@ -1030,24 +1087,24 @@ XLogWrite(XLogwrtRqst WriteRqst)
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* we might have no open file or the wrong one. However, we do
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* not need to fsync more than one file.
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*/
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if (openLogFile >= 0 &&
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!XLByteInPrevSeg(LogwrtResult.Write, openLogId, openLogSeg))
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if (sync_method != SYNC_METHOD_OPEN)
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{
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if (close(openLogFile) != 0)
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elog(STOP, "close(logfile %u seg %u) failed: %m",
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openLogId, openLogSeg);
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openLogFile = -1;
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if (openLogFile >= 0 &&
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!XLByteInPrevSeg(LogwrtResult.Write, openLogId, openLogSeg))
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{
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if (close(openLogFile) != 0)
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elog(STOP, "close(logfile %u seg %u) failed: %m",
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openLogId, openLogSeg);
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openLogFile = -1;
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}
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if (openLogFile < 0)
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{
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XLByteToPrevSeg(LogwrtResult.Write, openLogId, openLogSeg);
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openLogFile = XLogFileOpen(openLogId, openLogSeg, false);
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openLogOff = 0;
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}
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issue_xlog_fsync();
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}
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if (openLogFile < 0)
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{
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XLByteToPrevSeg(LogwrtResult.Write, openLogId, openLogSeg);
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openLogFile = XLogFileOpen(openLogId, openLogSeg, false);
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openLogOff = 0;
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}
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if (pg_fdatasync(openLogFile) != 0)
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elog(STOP, "fsync(logfile %u seg %u) failed: %m",
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openLogId, openLogSeg);
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LogwrtResult.Flush = LogwrtResult.Write;
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}
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@ -1191,7 +1248,8 @@ XLogFileInit(uint32 log, uint32 seg, bool *usexistent)
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*/
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if (*usexistent)
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{
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fd = BasicOpenFile(path, O_RDWR | PG_BINARY, S_IRUSR | S_IWUSR);
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fd = BasicOpenFile(path, O_RDWR | PG_BINARY | XLOG_SYNC_BIT,
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S_IRUSR | S_IWUSR);
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if (fd < 0)
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{
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if (errno != ENOENT)
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@ -1208,6 +1266,7 @@ XLogFileInit(uint32 log, uint32 seg, bool *usexistent)
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unlink(tpath);
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unlink(path);
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/* do not use XLOG_SYNC_BIT here --- want to fsync only at end of fill */
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fd = BasicOpenFile(tpath, O_RDWR | O_CREAT | O_EXCL | PG_BINARY,
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S_IRUSR | S_IWUSR);
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if (fd < 0)
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@ -1220,8 +1279,8 @@ XLogFileInit(uint32 log, uint32 seg, bool *usexistent)
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* allow "holes" in files, just seeking to the end doesn't allocate
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* intermediate space. This way, we know that we have all the space
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* and (after the fsync below) that all the indirect blocks are down
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* on disk. Therefore, fdatasync(2) will be sufficient to sync future
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* writes to the log file.
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* on disk. Therefore, fdatasync(2) or O_DSYNC will be sufficient to
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* sync future writes to the log file.
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*/
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MemSet(zbuffer, 0, sizeof(zbuffer));
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for (nbytes = 0; nbytes < XLogSegSize; nbytes += sizeof(zbuffer))
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@ -1261,7 +1320,8 @@ XLogFileInit(uint32 log, uint32 seg, bool *usexistent)
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log, seg);
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#endif
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fd = BasicOpenFile(path, O_RDWR | PG_BINARY, S_IRUSR | S_IWUSR);
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fd = BasicOpenFile(path, O_RDWR | PG_BINARY | XLOG_SYNC_BIT,
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S_IRUSR | S_IWUSR);
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if (fd < 0)
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elog(STOP, "InitReopen(logfile %u seg %u) failed: %m",
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log, seg);
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@ -1280,7 +1340,8 @@ XLogFileOpen(uint32 log, uint32 seg, bool econt)
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XLogFileName(path, log, seg);
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fd = BasicOpenFile(path, O_RDWR | PG_BINARY, S_IRUSR | S_IWUSR);
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fd = BasicOpenFile(path, O_RDWR | PG_BINARY | XLOG_SYNC_BIT,
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S_IRUSR | S_IWUSR);
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if (fd < 0)
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{
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if (econt && errno == ENOENT)
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@ -1845,7 +1906,8 @@ WriteControlFile(void)
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memset(buffer, 0, BLCKSZ);
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memcpy(buffer, ControlFile, sizeof(ControlFileData));
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fd = BasicOpenFile(ControlFilePath, O_RDWR | O_CREAT | O_EXCL | PG_BINARY, S_IRUSR | S_IWUSR);
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fd = BasicOpenFile(ControlFilePath, O_RDWR | O_CREAT | O_EXCL | PG_BINARY,
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S_IRUSR | S_IWUSR);
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if (fd < 0)
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elog(STOP, "WriteControlFile failed to create control file (%s): %m",
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ControlFilePath);
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@ -2852,3 +2914,120 @@ xlog_outrec(char *buf, XLogRecord *record)
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sprintf(buf + strlen(buf), ": %s",
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RmgrTable[record->xl_rmid].rm_name);
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}
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/*
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* GUC support routines
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*/
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bool
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check_xlog_sync_method(const char *method)
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{
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if (strcasecmp(method, "fsync") == 0) return true;
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#ifdef HAVE_FDATASYNC
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if (strcasecmp(method, "fdatasync") == 0) return true;
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#endif
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#ifdef OPEN_SYNC_FLAG
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if (strcasecmp(method, "open_sync") == 0) return true;
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#endif
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#ifdef OPEN_DATASYNC_FLAG
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if (strcasecmp(method, "open_datasync") == 0) return true;
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#endif
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return false;
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}
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void
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assign_xlog_sync_method(const char *method)
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{
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int new_sync_method;
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int new_sync_bit;
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if (strcasecmp(method, "fsync") == 0)
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{
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new_sync_method = SYNC_METHOD_FSYNC;
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new_sync_bit = 0;
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}
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#ifdef HAVE_FDATASYNC
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else if (strcasecmp(method, "fdatasync") == 0)
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{
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new_sync_method = SYNC_METHOD_FDATASYNC;
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new_sync_bit = 0;
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}
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#endif
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#ifdef OPEN_SYNC_FLAG
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else if (strcasecmp(method, "open_sync") == 0)
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{
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new_sync_method = SYNC_METHOD_OPEN;
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new_sync_bit = OPEN_SYNC_FLAG;
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}
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#endif
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#ifdef OPEN_DATASYNC_FLAG
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else if (strcasecmp(method, "open_datasync") == 0)
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{
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new_sync_method = SYNC_METHOD_OPEN;
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new_sync_bit = OPEN_DATASYNC_FLAG;
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}
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#endif
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else
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{
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/* Can't get here unless guc.c screwed up */
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elog(ERROR, "Bogus xlog sync method %s", method);
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new_sync_method = 0; /* keep compiler quiet */
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new_sync_bit = 0;
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}
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if (sync_method != new_sync_method || open_sync_bit != new_sync_bit)
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{
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/*
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* To ensure that no blocks escape unsynced, force an fsync on
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* the currently open log segment (if any). Also, if the open
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* flag is changing, close the log file so it will be reopened
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* (with new flag bit) at next use.
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*/
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if (openLogFile >= 0)
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{
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if (pg_fsync(openLogFile) != 0)
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elog(STOP, "fsync(logfile %u seg %u) failed: %m",
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openLogId, openLogSeg);
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if (open_sync_bit != new_sync_bit)
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{
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if (close(openLogFile) != 0)
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elog(STOP, "close(logfile %u seg %u) failed: %m",
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openLogId, openLogSeg);
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openLogFile = -1;
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}
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}
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sync_method = new_sync_method;
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open_sync_bit = new_sync_bit;
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}
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}
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/*
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* Issue appropriate kind of fsync (if any) on the current XLOG output file
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*/
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static void
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issue_xlog_fsync(void)
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{
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switch (sync_method)
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{
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case SYNC_METHOD_FSYNC:
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if (pg_fsync(openLogFile) != 0)
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elog(STOP, "fsync(logfile %u seg %u) failed: %m",
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openLogId, openLogSeg);
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break;
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#ifdef HAVE_FDATASYNC
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case SYNC_METHOD_FDATASYNC:
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if (pg_fdatasync(openLogFile) != 0)
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elog(STOP, "fdatasync(logfile %u seg %u) failed: %m",
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openLogId, openLogSeg);
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break;
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#endif
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case SYNC_METHOD_OPEN:
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/* write synced it already */
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break;
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default:
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elog(STOP, "bogus sync_method %d", sync_method);
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break;
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}
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}
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@ -4,7 +4,7 @@
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* Support for grand unified configuration scheme, including SET
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* command, configuration file, and command line options.
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*
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* $Header: /cvsroot/pgsql/src/backend/utils/misc/guc.c,v 1.32 2001/03/13 01:17:06 tgl Exp $
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* $Header: /cvsroot/pgsql/src/backend/utils/misc/guc.c,v 1.33 2001/03/16 05:44:33 tgl Exp $
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*
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* Copyright 2000 by PostgreSQL Global Development Group
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* Written by Peter Eisentraut <peter_e@gmx.net>.
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@ -20,6 +20,7 @@
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#include "utils/guc.h"
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#include "access/xlog.h"
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#include "commands/async.h"
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#include "libpq/auth.h"
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#include "libpq/pqcomm.h"
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@ -33,23 +34,17 @@
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#include "tcop/tcopprot.h"
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|
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/* XXX should be in a header file */
|
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/* XXX these should be in other modules' header files */
|
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extern bool Log_connections;
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|
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extern int CheckPointSegments;
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extern int CheckPointTimeout;
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extern int XLOGbuffers;
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extern int XLOGfiles;
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extern int XLOG_DEBUG;
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extern int CommitDelay;
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extern int CommitSiblings;
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|
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extern bool FixBTree;
|
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|
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#ifdef ENABLE_SYSLOG
|
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extern char *Syslog_facility;
|
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extern char *Syslog_ident;
|
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bool check_facility(const char *facility);
|
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static bool check_facility(const char *facility);
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#endif
|
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|
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/*
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@ -138,7 +133,8 @@ struct config_string
|
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GucContext context;
|
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char **variable;
|
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const char *default_val;
|
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bool (*parse_hook)(const char *);
|
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bool (*parse_hook)(const char *proposed);
|
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void (*assign_hook)(const char *newval);
|
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};
|
||||
|
||||
|
||||
@ -330,25 +326,29 @@ static struct config_string
|
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ConfigureNamesString[] =
|
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{
|
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{"krb_server_keyfile", PGC_POSTMASTER, &pg_krb_server_keyfile,
|
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PG_KRB_SRVTAB, NULL},
|
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|
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{"unix_socket_group", PGC_POSTMASTER, &Unix_socket_group,
|
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"", NULL},
|
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PG_KRB_SRVTAB, NULL, NULL},
|
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|
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#ifdef ENABLE_SYSLOG
|
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{"syslog_facility", PGC_POSTMASTER, &Syslog_facility,
|
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"LOCAL0", check_facility},
|
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"LOCAL0", check_facility, NULL},
|
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{"syslog_ident", PGC_POSTMASTER, &Syslog_ident,
|
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"postgres", NULL},
|
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"postgres", NULL, NULL},
|
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#endif
|
||||
|
||||
{"unix_socket_group", PGC_POSTMASTER, &Unix_socket_group,
|
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"", NULL, NULL},
|
||||
|
||||
{"unix_socket_directory", PGC_POSTMASTER, &UnixSocketDir,
|
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"", NULL},
|
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"", NULL, NULL},
|
||||
|
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{"virtual_host", PGC_POSTMASTER, &VirtualHost,
|
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"", NULL},
|
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"", NULL, NULL},
|
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|
||||
{NULL, 0, NULL, NULL, NULL}
|
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{"wal_sync_method", PGC_SIGHUP, &XLOG_sync_method,
|
||||
XLOG_sync_method_default,
|
||||
check_xlog_sync_method, assign_xlog_sync_method},
|
||||
|
||||
{NULL, 0, NULL, NULL, NULL, NULL}
|
||||
};
|
||||
|
||||
/******** end of options list ********/
|
||||
@ -723,7 +723,10 @@ set_config_option(const char * name, const char * value, GucContext
|
||||
elog(elevel, "out of memory");
|
||||
return false;
|
||||
}
|
||||
free(*conf->variable);
|
||||
if (conf->assign_hook)
|
||||
(conf->assign_hook)(str);
|
||||
if (*conf->variable)
|
||||
free(*conf->variable);
|
||||
*conf->variable = str;
|
||||
}
|
||||
}
|
||||
@ -737,7 +740,10 @@ set_config_option(const char * name, const char * value, GucContext
|
||||
elog(elevel, "out of memory");
|
||||
return false;
|
||||
}
|
||||
free(*conf->variable);
|
||||
if (conf->assign_hook)
|
||||
(conf->assign_hook)(str);
|
||||
if (*conf->variable)
|
||||
free(*conf->variable);
|
||||
*conf->variable = str;
|
||||
}
|
||||
break;
|
||||
@ -855,7 +861,7 @@ ParseLongOption(const char * string, char ** name, char ** value)
|
||||
|
||||
|
||||
#ifdef ENABLE_SYSLOG
|
||||
bool
|
||||
static bool
|
||||
check_facility(const char *facility)
|
||||
{
|
||||
if (strcasecmp(facility,"LOCAL0") == 0) return true;
|
||||
|
||||
@ -107,6 +107,8 @@
|
||||
#
|
||||
#wal_buffers = 8 # min 4
|
||||
#wal_files = 0 # range 0-64
|
||||
#wal_sync_method = fsync # fsync or fdatasync or open_sync or open_datasync
|
||||
# Note: default wal_sync_method varies across platforms
|
||||
#wal_debug = 0 # range 0-16
|
||||
#commit_delay = 0 # range 0-100000
|
||||
#commit_siblings = 5 # range 1-1000
|
||||
|
||||
@ -6,7 +6,7 @@
|
||||
* Portions Copyright (c) 1996-2001, PostgreSQL Global Development Group
|
||||
* Portions Copyright (c) 1994, Regents of the University of California
|
||||
*
|
||||
* $Id: xlog.h,v 1.20 2001/03/13 20:32:37 tgl Exp $
|
||||
* $Id: xlog.h,v 1.21 2001/03/16 05:44:33 tgl Exp $
|
||||
*/
|
||||
#ifndef XLOG_H
|
||||
#define XLOG_H
|
||||
@ -176,6 +176,15 @@ extern StartUpID ThisStartUpID; /* current SUI */
|
||||
extern bool InRecovery;
|
||||
extern XLogRecPtr MyLastRecPtr;
|
||||
|
||||
/* these variables are GUC parameters related to XLOG */
|
||||
extern int CheckPointSegments;
|
||||
extern int XLOGbuffers;
|
||||
extern int XLOGfiles;
|
||||
extern int XLOG_DEBUG;
|
||||
extern char *XLOG_sync_method;
|
||||
extern const char XLOG_sync_method_default[];
|
||||
|
||||
|
||||
extern XLogRecPtr XLogInsert(RmgrId rmid, uint8 info, XLogRecData *rdata);
|
||||
extern void XLogFlush(XLogRecPtr RecPtr);
|
||||
|
||||
@ -202,4 +211,7 @@ extern void GetRedoRecPtr(void);
|
||||
*/
|
||||
extern XLogRecPtr GetUndoRecPtr(void);
|
||||
|
||||
extern bool check_xlog_sync_method(const char *method);
|
||||
extern void assign_xlog_sync_method(const char *method);
|
||||
|
||||
#endif /* XLOG_H */
|
||||
|
||||
Reference in New Issue
Block a user