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Add temp_buffers GUC variable to allow users to determine the size

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of the local buffer arena for temporary table access.
This commit is contained in:
Tom Lane
2005-03-19 23:27:11 +00:00
parent d65522aeb6
commit 91728fa26c
8 changed files with 89 additions and 28 deletions
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46
src/backend/storage/buffer/localbuf.c
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@ -9,7 +9,7 @@
*
*
* IDENTIFICATION
* $PostgreSQL: pgsql/src/backend/storage/buffer/localbuf.c,v 1.65 2005/03/19 17:39:43 tgl Exp $
* $PostgreSQL: pgsql/src/backend/storage/buffer/localbuf.c,v 1.66 2005/03/19 23:27:05 tgl Exp $
*
*-------------------------------------------------------------------------
*/
@ -18,6 +18,7 @@
#include "storage/buf_internals.h"
#include "storage/bufmgr.h"
#include "storage/smgr.h"
#include "utils/guc.h"
#include "utils/memutils.h"
#include "utils/resowner.h"
@ -46,6 +47,9 @@ static int nextFreeLocalBuf = 0;
static HTAB *LocalBufHash = NULL;
static void InitLocalBuffers(void);
/*
* LocalBufferAlloc -
* Find or create a local buffer for the given page of the given relation.
@ -66,6 +70,10 @@ LocalBufferAlloc(Relation reln, BlockNumber blockNum, bool *foundPtr)
INIT_BUFFERTAG(newTag, reln, blockNum);
/* Initialize local buffers if first request in this session */
if (LocalBufHash == NULL)
InitLocalBuffers();
/* See if the desired buffer already exists */
hresult = (LocalBufferLookupEnt *)
hash_search(LocalBufHash, (void *) &newTag, HASH_FIND, NULL);
@ -238,32 +246,18 @@ WriteLocalBuffer(Buffer buffer, bool release)
}
/*
* InitLocalBuffer -
* InitLocalBuffers -
* init the local buffer cache. Since most queries (esp. multi-user ones)
* don't involve local buffers, we delay allocating actual memory for the
* buffers until we need them; just make the buffer headers here.
*/
void
InitLocalBuffer(void)
static void
InitLocalBuffers(void)
{
int nbufs = 64; /* should be from a GUC var */
int nbufs = num_temp_buffers;
HASHCTL info;
int i;
/* Create the lookup hash table */
MemSet(&info, 0, sizeof(info));
info.keysize = sizeof(BufferTag);
info.entrysize = sizeof(LocalBufferLookupEnt);
info.hash = tag_hash;
LocalBufHash = hash_create("Local Buffer Lookup Table",
nbufs,
&info,
HASH_ELEM | HASH_FUNCTION);
if (!LocalBufHash)
elog(ERROR, "could not initialize local buffer hash table");
/* Allocate and zero buffer headers and auxiliary arrays */
LocalBufferDescriptors = (BufferDesc *)
MemoryContextAllocZero(TopMemoryContext,
@ -291,6 +285,20 @@ InitLocalBuffer(void)
buf->buf_id = -i - 2;
}
/* Create the lookup hash table */
MemSet(&info, 0, sizeof(info));
info.keysize = sizeof(BufferTag);
info.entrysize = sizeof(LocalBufferLookupEnt);
info.hash = tag_hash;
LocalBufHash = hash_create("Local Buffer Lookup Table",
nbufs,
&info,
HASH_ELEM | HASH_FUNCTION);
if (!LocalBufHash)
elog(ERROR, "could not initialize local buffer hash table");
/* Initialization done, mark buffers allocated */
NLocBuffer = nbufs;
}