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Code review for ARC patch. Eliminate static variables, improve handling

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of VACUUM cases so that VACUUM requests don't affect the ARC state at all,
avoid corner case where BufferSync would uselessly rewrite a buffer that
no longer contains the page that was to be flushed.  Make some minor
other cleanups in and around the bufmgr as well, such as moving PinBuffer
and UnpinBuffer into bufmgr.c where they really belong.
This commit is contained in:
Tom Lane
2004-04-19 23:27:17 +00:00
parent 8f73bbae85
commit 011c3e62e7
7 changed files with 715 additions and 730 deletions
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44
src/backend/storage/buffer/buf_table.c
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@ -3,46 +3,42 @@
* buf_table.c
* routines for finding buffers in the buffer pool.
*
* NOTE: these days, what this table actually provides is a mapping from
* BufferTags to CDB indexes, not directly to buffers. The function names
* are thus slight misnomers.
*
* Note: all routines in this file assume that the BufMgrLock is held
* by the caller, so no synchronization is needed.
*
*
* Portions Copyright (c) 1996-2003, PostgreSQL Global Development Group
* Portions Copyright (c) 1994, Regents of the University of California
*
*
* IDENTIFICATION
* $PostgreSQL: pgsql/src/backend/storage/buffer/buf_table.c,v 1.34 2003/12/14 00:34:47 neilc Exp $
* $PostgreSQL: pgsql/src/backend/storage/buffer/buf_table.c,v 1.35 2004/04/19 23:27:17 tgl Exp $
*
*-------------------------------------------------------------------------
*/
/*
* OLD COMMENTS
*
* Data Structures:
*
* Buffers are identified by their BufferTag (buf.h). This
* file contains routines for allocating a shmem hash table to
* map buffer tags to buffer descriptors.
*
* Synchronization:
*
* All routines in this file assume BufMgrLock is held by their caller.
*/
#include "postgres.h"
#include "storage/buf_internals.h"
#include "storage/bufmgr.h"
static HTAB *SharedBufHash;
/*
* Initialize shmem hash table for mapping buffers
* size is the desired hash table size (2*NBuffers for ARC algorithm)
*/
void
InitBufTable(int size)
{
HASHCTL info;
/* assume lock is held */
/* assume no locking is needed yet */
/* BufferTag maps to Buffer */
info.keysize = sizeof(BufferTag);
@ -60,6 +56,7 @@ InitBufTable(int size)
/*
* BufTableLookup
* Lookup the given BufferTag; return CDB index, or -1 if not found
*/
int
BufTableLookup(BufferTag *tagPtr)
@ -78,10 +75,11 @@ BufTableLookup(BufferTag *tagPtr)
}
/*
* BufTableDelete
* BufTableInsert
* Insert a hashtable entry for given tag and CDB index
*/
bool
BufTableInsert(BufferTag *tagPtr, Buffer buf_id)
void
BufTableInsert(BufferTag *tagPtr, int cdb_id)
{
BufferLookupEnt *result;
bool found;
@ -97,14 +95,14 @@ BufTableInsert(BufferTag *tagPtr, Buffer buf_id)
if (found) /* found something else in the table? */
elog(ERROR, "shared buffer hash table corrupted");
result->id = buf_id;
return TRUE;
result->id = cdb_id;
}
/*
* BufTableDelete
* Delete the hashtable entry for given tag
*/
bool
void
BufTableDelete(BufferTag *tagPtr)
{
BufferLookupEnt *result;
@ -114,6 +112,4 @@ BufTableDelete(BufferTag *tagPtr)
if (!result) /* shouldn't happen */
elog(ERROR, "shared buffer hash table corrupted");
return TRUE;
}