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Scan the buffer pool just once, not once per fork, during relation drop.

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This provides a speedup of about 4X when NBuffers is large enough.
There is also a useful reduction in sinval traffic, since we
only do CacheInvalidateSmgr() once not once per fork.

Simon Riggs, reviewed and somewhat revised by Tom Lane
This commit is contained in:
Tom Lane
2012-06-07 17:42:27 -04:00
parent 5baf6da717
commit ece01aae47
9 changed files with 150 additions and 23 deletions
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42
src/backend/storage/buffer/bufmgr.c
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@ -2020,7 +2020,7 @@ BufferIsPermanent(Buffer buffer)
* DropRelFileNodeBuffers
*
* This function removes from the buffer pool all the pages of the
* specified relation that have block numbers >= firstDelBlock.
* specified relation fork that have block numbers >= firstDelBlock.
* (In particular, with firstDelBlock = 0, all pages are removed.)
* Dirty pages are simply dropped, without bothering to write them
* out first. Therefore, this is NOT rollback-able, and so should be
@ -2089,6 +2089,46 @@ DropRelFileNodeBuffers(RelFileNodeBackend rnode, ForkNumber forkNum,
}
}
/* ---------------------------------------------------------------------
* DropRelFileNodeAllBuffers
*
* This function removes from the buffer pool all the pages of all
* forks of the specified relation. It's equivalent to calling
* DropRelFileNodeBuffers once per fork with firstDelBlock = 0.
* --------------------------------------------------------------------
*/
void
DropRelFileNodeAllBuffers(RelFileNodeBackend rnode)
{
int i;
/* If it's a local relation, it's localbuf.c's problem. */
if (rnode.backend != InvalidBackendId)
{
if (rnode.backend == MyBackendId)
DropRelFileNodeAllLocalBuffers(rnode.node);
return;
}
for (i = 0; i < NBuffers; i++)
{
volatile BufferDesc *bufHdr = &BufferDescriptors[i];
/*
* As in DropRelFileNodeBuffers, an unlocked precheck should be safe
* and saves some cycles.
*/
if (!RelFileNodeEquals(bufHdr->tag.rnode, rnode.node))
continue;
LockBufHdr(bufHdr);
if (RelFileNodeEquals(bufHdr->tag.rnode, rnode.node))
InvalidateBuffer(bufHdr); /* releases spinlock */
else
UnlockBufHdr(bufHdr);
}
}
/* ---------------------------------------------------------------------
* DropDatabaseBuffers
*