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Modify RelationGetBufferForTuple() so that we only do lseek and lock

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when we need to move to a new page; as long as we can insert the new
tuple on the same page as before, we only need LockBuffer and not the
expensive stuff.  Also, twiddle bufmgr interfaces to avoid redundant
lseeks in RelationGetBufferForTuple and BufferAlloc.  Successive inserts
now require one lseek per page added, rather than one per tuple with
several additional ones at each page boundary as happened before.
Lock contention when multiple backends are inserting in same table
is also greatly reduced.
This commit is contained in:
Tom Lane
2001-05-12 19:58:28 +00:00
parent d9f55edc2c
commit eedb7d18fa
5 changed files with 159 additions and 104 deletions
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8
src/backend/storage/buffer/localbuf.c
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@ -16,7 +16,7 @@
*
*
* IDENTIFICATION
* $Header: /cvsroot/pgsql/src/backend/storage/buffer/localbuf.c,v 1.40 2001/03/22 03:59:44 momjian Exp $
* $Header: /cvsroot/pgsql/src/backend/storage/buffer/localbuf.c,v 1.41 2001/05/12 19:58:27 tgl Exp $
*
*-------------------------------------------------------------------------
*/
@ -54,12 +54,6 @@ LocalBufferAlloc(Relation reln, BlockNumber blockNum, bool *foundPtr)
int i;
BufferDesc *bufHdr = (BufferDesc *) NULL;
if (blockNum == P_NEW)
{
blockNum = reln->rd_nblocks;
reln->rd_nblocks++;
}
/* a low tech search for now -- not optimized for scans */
for (i = 0; i < NLocBuffer; i++)
{