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| author | Bruce Momjian <bruce@momjian.us> | 2005-06-04 20:14:12 +0000 |
|---|---|---|
| committer | Bruce Momjian <bruce@momjian.us> | 2005-06-04 20:14:12 +0000 |
| commit | 3cf1fd3263ee4fd585df80fb235c855b8a97426d (patch) | |
| tree | 8a3f98050d3a26528a0f563648394e814ce88b96 /src | |
| parent | e18e8f873594fd4ff2f12e734a624102d3ef1e39 (diff) | |
| download | postgresql-3cf1fd3263ee4fd585df80fb235c855b8a97426d.tar.gz postgresql-3cf1fd3263ee4fd585df80fb235c855b8a97426d.zip | |
Tom Lane <tgl@sss.pgh.pa.us> writes:
> a_ogawa <a_ogawa@hi-ho.ne.jp> writes:
> > It is a reasonable idea. However, the majority part of MemSet was not
> > able to be avoided by this idea. Because the per-tuple contexts are used
> > at the early stage of executor.
>
> Drat. Well, what about changing that? We could introduce additional
> contexts or change the startup behavior so that the ones that are
> frequently reset don't have any data in them unless you are working
> with pass-by-ref values inside the inner loop.
That might be possible. However, I think that we should change only
aset.c about this article.
I thought further: We can check whether context was used from the last
reset even when blocks list is not empty. Please see attached patch.
The effect of the patch that I measured is as follows:
o Execution time that executed the SQL ten times.
(1)Linux(CPU: Pentium III, Compiler option: -O2)
- original: 24.960s
- patched : 23.114s
(2)Linux(CPU: Pentium 4, Compiler option: -O2)
- original: 8.730s
- patched : 7.962s
(3)Solaris(CPU: Ultra SPARC III, Compiler option: -O2)
- original: 37.0s
- patched : 33.7s
Atsushi Ogawa (a_ogawa)
Diffstat (limited to 'src')
| -rw-r--r-- | src/backend/utils/mmgr/aset.c | 13 |
1 files changed, 12 insertions, 1 deletions
diff --git a/src/backend/utils/mmgr/aset.c b/src/backend/utils/mmgr/aset.c index 4f60b186c27..f7550929f1f 100644 --- a/src/backend/utils/mmgr/aset.c +++ b/src/backend/utils/mmgr/aset.c @@ -11,7 +11,7 @@ * Portions Copyright (c) 1994, Regents of the University of California * * IDENTIFICATION - * $PostgreSQL: pgsql/src/backend/utils/mmgr/aset.c,v 1.60 2005/05/14 20:29:13 tgl Exp $ + * $PostgreSQL: pgsql/src/backend/utils/mmgr/aset.c,v 1.61 2005/06/04 20:14:12 momjian Exp $ * * NOTE: * This is a new (Feb. 05, 1999) implementation of the allocation set @@ -399,6 +399,17 @@ AllocSetReset(MemoryContext context) if (block == NULL) return; + /* + * When blocks list has only "keeper" block and freeptr of the block + * is initial value, the context is not used from last reset. + */ + if (block == set->keeper && block->next == NULL) + { + char *datastart = ((char *) block) + ALLOC_BLOCKHDRSZ; + if (block->freeptr == datastart) + return; + } + /* Clear chunk freelists */ MemSetAligned(set->freelist, 0, sizeof(set->freelist)); |