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/*-------------------------------------------------------------------------
*
* sinvaladt.h--
* POSTGRES shared cache invalidation segment definitions.
*
*
* Copyright (c) 1994, Regents of the University of California
*
* $Id: sinvaladt.h,v 1.10 1998/09/01 04:38:36 momjian Exp $
*
*-------------------------------------------------------------------------
*/
#ifndef SINVALADT_H
#define SINVALADT_H
#include <storage/itemptr.h>
#include <storage/ipc.h>
/*
* The structure of the shared cache invaidation segment
*
*/
/*
A------------- Header info --------------
criticalSectionSemaphoreId
generalSemaphoreId
startEntrySection (offset a)
endEntrySection (offset a + b)
startFreeSpace (offset relative to B)
startEntryChain (offset relatiev to B)
endEntryChain (offset relative to B)
numEntries
maxNumEntries
procState[MaxBackendId] --> limit
resetState (bool)
a tag (POSTID)
B------------- Start entry section -------
SISegEntry --> entryData --> ... (see SharedInvalidData!)
isfree (bool)
next (offset to next entry in chain )
b .... (dynamically growing down)
C----------------End shared segment -------
*/
/* Parameters (configurable) *******************************************/
#define MaxBackendId 64 /* maximum number of backends */
#define MAXNUMMESSAGES 4000 /* maximum number of messages in seg */
#define InvalidOffset 1000000000 /* a invalid offset (End of
* chain) */
typedef struct ProcState
{
int limit; /* the number of read messages */
bool resetState; /* true, if backend has to reset its state */
int tag; /* special tag, recieved from the
* postmaster */
} ProcState;
typedef struct SISeg
{
IpcSemaphoreId criticalSectionSemaphoreId; /* semaphore id */
IpcSemaphoreId generalSemaphoreId; /* semaphore id */
Offset startEntrySection; /* (offset a) */
Offset endEntrySection;/* (offset a + b) */
Offset startFreeSpace; /* (offset relative to B) */
Offset startEntryChain;/* (offset relative to B) */
Offset endEntryChain; /* (offset relative to B) */
int numEntries;
int maxNumEntries;
ProcState procState[MaxBackendId]; /* reflects the
* invalidation state */
/* here starts the entry section, controlled by offsets */
} SISeg;
#define SizeSISeg sizeof(SISeg)
typedef struct SharedInvalidData
{
int cacheId; /* XXX */
Index hashIndex;
ItemPointerData pointerData;
} SharedInvalidData;
typedef SharedInvalidData *SharedInvalid;
typedef struct SISegEntry
{
SharedInvalidData entryData;/* the message data */
bool isfree; /* entry free? */
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 */
} SISegOffsets;
/****************************************************************************/
/* synchronization of the shared buffer access */
/* access to the buffer is synchronized by the lock manager !! */
/****************************************************************************/
#define SI_LockStartValue 255
#define SI_SharedLock (-1)
#define SI_ExclusiveLock (-255)
extern SISeg *shmInvalBuffer;
/*
* prototypes for functions in sinvaladt.c
*/
extern int SIBackendInit(SISeg *segInOutP);
extern int SISegmentInit(bool killExistingSegment, IPCKey key);
extern bool SISetDataEntry(SISeg *segP, SharedInvalidData *data);
extern void SISetProcStateInvalid(SISeg *segP);
extern bool SIDelDataEntry(SISeg *segP);
extern void SIReadEntryData(SISeg *segP, int backendId,
void (*invalFunction) (), void (*resetFunction) ());
extern void SIDelExpiredDataEntries(SISeg *segP);
#endif /* SINVALADT_H */
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