Index: src/backend/access/transam/xlog.c
===================================================================
RCS file: /cvsroot/pgsql/src/backend/access/transam/xlog.c,v
retrieving revision 1.237
diff -c -c -r1.237 xlog.c
*** src/backend/access/transam/xlog.c	20 Apr 2006 04:07:38 -0000	1.237
--- src/backend/access/transam/xlog.c	14 Jun 2006 17:38:10 -0000
***************
*** 478,483 ****
--- 478,484 ----
  					   bool use_lock);
  static int	XLogFileOpen(uint32 log, uint32 seg);
  static int	XLogFileRead(uint32 log, uint32 seg, int emode);
+ static void	XLogFileClose(void);
  static bool RestoreArchivedFile(char *path, const char *xlogfname,
  					const char *recovername, off_t expectedSize);
  static int	PreallocXlogFiles(XLogRecPtr endptr);
***************
*** 1384,1397 ****
  			 */
  			Assert(npages == 0);
  			if (openLogFile >= 0)
! 			{
! 				if (close(openLogFile))
! 					ereport(PANIC,
! 							(errcode_for_file_access(),
! 						errmsg("could not close log file %u, segment %u: %m",
! 							   openLogId, openLogSeg)));
! 				openLogFile = -1;
! 			}
  			XLByteToPrevSeg(LogwrtResult.Write, openLogId, openLogSeg);
  
  			/* create/use new log file */
--- 1385,1391 ----
  			 */
  			Assert(npages == 0);
  			if (openLogFile >= 0)
! 				XLogFileClose();
  			XLByteToPrevSeg(LogwrtResult.Write, openLogId, openLogSeg);
  
  			/* create/use new log file */
***************
*** 1567,1580 ****
  		{
  			if (openLogFile >= 0 &&
  				!XLByteInPrevSeg(LogwrtResult.Write, openLogId, openLogSeg))
! 			{
! 				if (close(openLogFile))
! 					ereport(PANIC,
! 							(errcode_for_file_access(),
! 						errmsg("could not close log file %u, segment %u: %m",
! 							   openLogId, openLogSeg)));
! 				openLogFile = -1;
! 			}
  			if (openLogFile < 0)
  			{
  				XLByteToPrevSeg(LogwrtResult.Write, openLogId, openLogSeg);
--- 1561,1567 ----
  		{
  			if (openLogFile >= 0 &&
  				!XLByteInPrevSeg(LogwrtResult.Write, openLogId, openLogSeg))
! 				XLogFileClose();
  			if (openLogFile < 0)
  			{
  				XLByteToPrevSeg(LogwrtResult.Write, openLogId, openLogSeg);
***************
*** 2153,2158 ****
--- 2140,2173 ----
  }
  
  /*
+  * Close the current logfile segment for writing.
+  */
+ static void
+ XLogFileClose(void)
+ {
+ 	Assert(openLogFile >= 0);
+ 
+ #ifdef _POSIX_ADVISORY_INFO
+ 	/*
+ 	 * WAL caches will not be accessed in the future, so we advise OS to
+ 	 * free them. But we will not do so if WAL archiving is active,
+ 	 * because archivers might use the caches to read the WAL segment.
+ 	 * While O_DIRECT works for O_SYNC, posix_fadvise() works for fsync()
+ 	 * and O_SYNC, and some platforms only have posix_fadvise().
+ 	 */
+ 	if (!XLogArchivingActive())
+ 		posix_fadvise(openLogFile, 0, 0, POSIX_FADV_DONTNEED);
+ #endif
+ 
+ 	if (close(openLogFile))
+ 		ereport(PANIC,
+ 			(errcode_for_file_access(),
+ 			errmsg("could not close log file %u, segment %u: %m",
+ 				   openLogId, openLogSeg)));
+ 	openLogFile = -1;
+ }
+ 
+ /*
   * Attempt to retrieve the specified file from off-line archival storage.
   * If successful, fill "path" with its complete path (note that this will be
   * a temp file name that doesn't follow the normal naming convention), and
***************
*** 5609,5622 ****
  						 errmsg("could not fsync log file %u, segment %u: %m",
  								openLogId, openLogSeg)));
  			if (open_sync_bit != new_sync_bit)
! 			{
! 				if (close(openLogFile))
! 					ereport(PANIC,
! 							(errcode_for_file_access(),
! 						errmsg("could not close log file %u, segment %u: %m",
! 							   openLogId, openLogSeg)));
! 				openLogFile = -1;
! 			}
  		}
  		sync_method = new_sync_method;
  		open_sync_bit = new_sync_bit;
--- 5624,5630 ----
  						 errmsg("could not fsync log file %u, segment %u: %m",
  								openLogId, openLogSeg)));
  			if (open_sync_bit != new_sync_bit)
! 				XLogFileClose();
  		}
  		sync_method = new_sync_method;
  		open_sync_bit = new_sync_bit;