Simon Riggs wrote:
>
> On Wed, 2008-09-17 at 16:25 -0400, Alvaro Herrera wrote:
>
> > We've been profiling a large system (8 CPUs, 64 GB of memory, some
> > dozens of disks) which seems rather more swamped than it should. Part
> > of the problem seems to come from CleanupTempFiles, the second entry in
> > oprofile output.
>
> I'm glad you've observed this also. I saw it about two years ago but
> wasn't able to convince anyone else it existed at the time.
I couldn't find it in the archives.
> Simple solution is to have a state variable so you can see whether a
> backend has created an temp files in this transaction. Most don't, so I
> think the above two solutions are overkill. If we created any, scan for
> them, if not, don't. Just a simple boolean state, just as we have for
> AtEOXact_RelationCache().
Ah -- like this?
--
Alvaro Herrera http://www.CommandPrompt.com/
The PostgreSQL Company - Command Prompt, Inc.
Index: src/backend/storage/file/fd.c
===================================================================
RCS file: /home/alvherre/Code/cvs/pgsql/src/backend/storage/file/fd.c,v
retrieving revision 1.143
diff -c -p -r1.143 fd.c
*** src/backend/storage/file/fd.c 1 Jan 2008 19:45:51 -0000 1.143
--- src/backend/storage/file/fd.c 17 Sep 2008 21:33:28 -0000
*************** static int max_safe_fds = 32; /* default
*** 121,126 ****
--- 121,132 ----
#define FD_TEMPORARY (1 << 0) /* T = delete when closed */
#define FD_XACT_TEMPORARY (1 << 1) /* T = delete at eoXact */
+ /*
+ * Flag to tell whether it's worth scanning VfdCache looking for temp files to
+ * close
+ */
+ static bool any_temporary_files = false;
+
typedef struct vfd
{
signed short fd; /* current FD, or VFD_CLOSED if none */
*************** OpenTemporaryFile(bool interXact)
*** 889,894 ****
--- 895,903 ----
{
VfdCache[file].fdstate |= FD_XACT_TEMPORARY;
VfdCache[file].create_subid = GetCurrentSubTransactionId();
+
+ /* ensure cleanup happens at eoxact */
+ any_temporary_files = true;
}
return file;
*************** AtEOSubXact_Files(bool isCommit, SubTran
*** 1603,1609 ****
{
Index i;
! if (SizeVfdCache > 0)
{
Assert(FileIsNotOpen(0)); /* Make sure ring not corrupted */
for (i = 1; i < SizeVfdCache; i++)
--- 1612,1618 ----
{
Index i;
! if (SizeVfdCache > 0 && any_temporary_files)
{
Assert(FileIsNotOpen(0)); /* Make sure ring not corrupted */
for (i = 1; i < SizeVfdCache; i++)
*************** CleanupTempFiles(bool isProcExit)
*** 1679,1685 ****
{
Index i;
! if (SizeVfdCache > 0)
{
Assert(FileIsNotOpen(0)); /* Make sure ring not corrupted */
for (i = 1; i < SizeVfdCache; i++)
--- 1688,1694 ----
{
Index i;
! if (SizeVfdCache > 0 && (isProcExit || any_temporary_files))
{
Assert(FileIsNotOpen(0)); /* Make sure ring not corrupted */
for (i = 1; i < SizeVfdCache; i++)
*************** CleanupTempFiles(bool isProcExit)
*** 1697,1702 ****
--- 1706,1713 ----
FileClose(i);
}
}
+
+ any_temporary_files = false;
}
while (numAllocatedDescs > 0)
--
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