Re: Removing pgsql_tmp files

[Tom Lane <tgl@xxxxxxxxxxxxx>]

Alvaro Herrera <alvherre@xxxxxxxxxxxxxxxxx> writes:
> Excerpts from Tom Lane's message of lun nov 08 22:29:28 -0300 2010:
>> I think we need to re-order the operations there to ensure that the
>> unlink will still happen if the ereport gets interrupted.

> Would it work to put the removal inside a PG_CATCH block?

Well, that still begs the question of what to do exactly.  After some
thought I believe the attached is the best fix.

			regards, tom lane

diff --git a/src/backend/storage/file/fd.c b/src/backend/storage/file/fd.c
index d9ab5e1ea2452131c2778acca6ad913ad4b333af..fd5ec7805fdcaedf73c3fa6aaa1a35970cf8e6db 100644
*** a/src/backend/storage/file/fd.c
--- b/src/backend/storage/file/fd.c
*************** void
*** 1032,1038 ****
  FileClose(File file)
  {
  	Vfd		   *vfdP;
- 	struct stat filestats;
  
  	Assert(FileIsValid(file));
  
--- 1032,1037 ----
*************** FileClose(File file)
*** 1055,1069 ****
  	}
  
  	/*
! 	 * Delete the file if it was temporary
  	 */
  	if (vfdP->fdstate & FD_TEMPORARY)
  	{
! 		/* reset flag so that die() interrupt won't cause problems */
  		vfdP->fdstate &= ~FD_TEMPORARY;
  		if (log_temp_files >= 0)
  		{
! 			if (stat(vfdP->fileName, &filestats) == 0)
  			{
  				if ((filestats.st_size / 1024) >= log_temp_files)
  					ereport(LOG,
--- 1054,1089 ----
  	}
  
  	/*
! 	 * Delete the file if it was temporary, and make a log entry if wanted
  	 */
  	if (vfdP->fdstate & FD_TEMPORARY)
  	{
! 		/*
! 		 * If we get an error, as could happen within the ereport/elog calls,
! 		 * we'll come right back here during transaction abort.  Reset the
! 		 * flag to ensure that we can't get into an infinite loop.  This code
! 		 * is arranged to ensure that the worst-case consequence is failing
! 		 * to emit log message(s), not failing to attempt the unlink.
! 		 */
  		vfdP->fdstate &= ~FD_TEMPORARY;
+ 
  		if (log_temp_files >= 0)
  		{
! 			struct stat filestats;
! 			int		stat_errno;
! 
! 			/* first try the stat() */
! 			if (stat(vfdP->fileName, &filestats))
! 				stat_errno = errno;
! 			else
! 				stat_errno = 0;
! 
! 			/* in any case do the unlink */
! 			if (unlink(vfdP->fileName))
! 				elog(LOG, "could not unlink file \"%s\": %m", vfdP->fileName);
! 
! 			/* and last report the stat results */
! 			if (stat_errno == 0)
  			{
  				if ((filestats.st_size / 1024) >= log_temp_files)
  					ereport(LOG,
*************** FileClose(File file)
*** 1072,1081 ****
  									(unsigned long) filestats.st_size)));
  			}
  			else
  				elog(LOG, "could not stat file \"%s\": %m", vfdP->fileName);
  		}
- 		if (unlink(vfdP->fileName))
- 			elog(LOG, "could not unlink file \"%s\": %m", vfdP->fileName);
  	}
  
  	/* Unregister it from the resource owner */
--- 1092,1108 ----
  									(unsigned long) filestats.st_size)));
  			}
  			else
+ 			{
+ 				errno = stat_errno;
  				elog(LOG, "could not stat file \"%s\": %m", vfdP->fileName);
+ 			}
+ 		}
+ 		else
+ 		{
+ 			/* easy case, just do the unlink */
+ 			if (unlink(vfdP->fileName))
+ 				elog(LOG, "could not unlink file \"%s\": %m", vfdP->fileName);
  		}
  	}
  
  	/* Unregister it from the resource owner */

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