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Repair performance problem in SI segment manipulations: iterating

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through MAXBACKENDS array entries used to be fine when MAXBACKENDS = 64.
It's not so cool with MAXBACKENDS = 1024 (or more!), especially not in a
frequently-used routine like SIDelExpiredDataEntries.  Repair by making
procState array size be the soft MaxBackends limit rather than the hard
limit, and by converting SIGetProcStateLimit() to a macro.
This commit is contained in:
Tom Lane
1999-05-28 17:03:31 +00:00
parent 33c6d6099d
commit dc6d404959
5 changed files with 62 additions and 73 deletions
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26
src/include/storage/sinvaladt.h
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@@ -6,7 +6,7 @@
*
* Copyright (c) 1994, Regents of the University of California
*
* $Id: sinvaladt.h,v 1.13 1999/05/25 16:14:46 momjian Exp $
* $Id: sinvaladt.h,v 1.14 1999/05/28 17:03:30 tgl Exp $
*
*-------------------------------------------------------------------------
*/
@@ -31,7 +31,8 @@ A------------- Header info --------------
endEntryChain (offset relative to B)
numEntries
maxNumEntries
procState[MAXBACKENDS] --> limit
maxBackends
procState[maxBackends] --> limit
resetState (bool)
a tag (POSTID)
B------------- Start entry section -------
@@ -70,12 +71,18 @@ typedef struct SISeg
Offset endEntryChain; /* (offset relative to B) */
int numEntries;
int maxNumEntries;
ProcState procState[MAXBACKENDS]; /* reflects the invalidation state */
/* here starts the entry section, controlled by offsets */
int maxBackends; /* size of procState array */
/*
* We declare procState as 1 entry because C wants a fixed-size array,
* but actually it is maxBackends entries long.
*/
ProcState procState[1]; /* reflects the invalidation state */
/*
* The entry section begins after the end of the procState array.
* Everything there is controlled by offsets.
*/
} SISeg;
#define SizeSISeg sizeof(SISeg)
typedef struct SharedInvalidData
{
int cacheId; /* XXX */
@@ -93,13 +100,11 @@ typedef struct SISegEntry
Offset next; /* offset to next entry */
} SISegEntry;
#define SizeOfOneSISegEntry sizeof(SISegEntry)
typedef struct SISegOffsets
{
Offset startSegment; /* always 0 (for now) */
Offset offsetToFirstEntry; /* A + a = B */
Offset offsetToEndOfSegemnt; /* A + a + b */
Offset offsetToEndOfSegment; /* A + a + b */
} SISegOffsets;
@@ -118,7 +123,8 @@ extern SISeg *shmInvalBuffer;
* prototypes for functions in sinvaladt.c
*/
extern int SIBackendInit(SISeg *segInOutP);
extern int SISegmentInit(bool killExistingSegment, IPCKey key);
extern int SISegmentInit(bool killExistingSegment, IPCKey key,
int maxBackends);
extern bool SISetDataEntry(SISeg *segP, SharedInvalidData *data);
extern void SISetProcStateInvalid(SISeg *segP);