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In ReadOrZeroBuffer (and related entry points), don't bother to call

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PageHeaderIsValid when we zero the buffer instead of reading the page in.
The actual performance improvement is probably marginal since this function
isn't very heavily used, but a cycle saved is a cycle earned.

Zdenek Kotala
This commit is contained in:
Tom Lane 2008-08-05 15:09:04 +00:00
parent 70d756970b
commit d8b04d5fac
1 changed files with 23 additions and 20 deletions
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5
src/backend/storage/buffer/bufmgr.c
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@ -8,7 +8,7 @@
*
*
* IDENTIFICATION
* $PostgreSQL: pgsql/src/backend/storage/buffer/bufmgr.c,v 1.235 2008/08/01 13:16:08 alvherre Exp $
* $PostgreSQL: pgsql/src/backend/storage/buffer/bufmgr.c,v 1.236 2008/08/05 15:09:04 tgl Exp $
*
*-------------------------------------------------------------------------
*/
@ -352,7 +352,9 @@ ReadBuffer_common(SMgrRelation smgr, bool isLocalBuf, BlockNumber blockNum,
if (zeroPage)
MemSet((char *) bufBlock, 0, BLCKSZ);
else
{
smgrread(smgr, blockNum, (char *) bufBlock);
/* check for garbage data */
if (!PageHeaderIsValid((PageHeader) bufBlock))
{
@ -376,6 +378,7 @@ ReadBuffer_common(SMgrRelation smgr, bool isLocalBuf, BlockNumber blockNum,
smgr->smgr_rnode.relNode)));
}
}
}
if (isLocalBuf)
{