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/*-------------------------------------------------------------------------
*
* sinval.c
* POSTGRES shared cache invalidation communication code.
*
* Copyright (c) 1994, Regents of the University of California
*
*
* IDENTIFICATION
* $Header: /cvsroot/pgsql/src/backend/storage/ipc/sinval.c,v 1.18 1999/09/06 19:37:38 tgl Exp $
*
*-------------------------------------------------------------------------
*/
/* #define INVALIDDEBUG 1 */
#include <sys/types.h>
#include "postgres.h"
#include "storage/backendid.h"
#include "storage/sinval.h"
#include "storage/sinvaladt.h"
SPINLOCK SInvalLock = (SPINLOCK) NULL;
/****************************************************************************/
/* CreateSharedInvalidationState() Create a buffer segment */
/* */
/* should be called only by the POSTMASTER */
/****************************************************************************/
void
CreateSharedInvalidationState(IPCKey key, int maxBackends)
{
int status;
/* SInvalLock gets set in spin.c, during spinlock init */
status = SISegmentInit(true, IPCKeyGetSIBufferMemoryBlock(key),
maxBackends);
if (status == -1)
elog(FATAL, "CreateSharedInvalidationState: failed segment init");
}
/****************************************************************************/
/* AttachSharedInvalidationState(key) Attach to existing buffer segment */
/* */
/* should be called by each backend during startup */
/****************************************************************************/
void
AttachSharedInvalidationState(IPCKey key)
{
int status;
if (key == PrivateIPCKey)
{
CreateSharedInvalidationState(key, 16);
return;
}
/* SInvalLock gets set in spin.c, during spinlock init */
status = SISegmentInit(false, IPCKeyGetSIBufferMemoryBlock(key), 0);
if (status == -1)
elog(FATAL, "AttachSharedInvalidationState: failed segment init");
}
/*
* InitSharedInvalidationState
* Initialize new backend's state info in buffer segment.
* Must be called after AttachSharedInvalidationState().
*/
void
InitSharedInvalidationState(void)
{
SpinAcquire(SInvalLock);
if (!SIBackendInit(shmInvalBuffer))
{
SpinRelease(SInvalLock);
elog(FATAL, "Backend cache invalidation initialization failed");
}
SpinRelease(SInvalLock);
}
/*
* RegisterSharedInvalid
* Add a shared-cache-invalidation message to the global SI message queue.
*
* Note:
* Assumes hash index is valid.
* Assumes item pointer is valid.
*/
void
RegisterSharedInvalid(int cacheId, /* XXX */
Index hashIndex,
ItemPointer pointer)
{
SharedInvalidData newInvalid;
bool insertOK;
/*
* This code has been hacked to accept two types of messages. This
* might be treated more generally in the future.
*
* (1) cacheId= system cache id hashIndex= system cache hash index for a
* (possibly) cached tuple pointer= pointer of (possibly) cached tuple
*
* (2) cacheId= special non-syscache id hashIndex= object id contained in
* (possibly) cached relation descriptor pointer= null
*/
newInvalid.cacheId = cacheId;
newInvalid.hashIndex = hashIndex;
if (ItemPointerIsValid(pointer))
ItemPointerCopy(pointer, &newInvalid.pointerData);
else
ItemPointerSetInvalid(&newInvalid.pointerData);
SpinAcquire(SInvalLock);
insertOK = SIInsertDataEntry(shmInvalBuffer, &newInvalid);
SpinRelease(SInvalLock);
if (! insertOK)
elog(NOTICE, "RegisterSharedInvalid: SI buffer overflow");
}
/*
* InvalidateSharedInvalid
* Process shared-cache-invalidation messages waiting for this backend
*/
void
InvalidateSharedInvalid(void (*invalFunction) (),
void (*resetFunction) ())
{
SharedInvalidData data;
int getResult;
bool gotMessage = false;
for (;;)
{
SpinAcquire(SInvalLock);
getResult = SIGetDataEntry(shmInvalBuffer, MyBackendId, &data);
SpinRelease(SInvalLock);
if (getResult == 0)
break; /* nothing more to do */
if (getResult < 0)
{
/* got a reset message */
elog(NOTICE, "InvalidateSharedInvalid: cache state reset");
resetFunction();
}
else
{
/* got a normal data message */
invalFunction(data.cacheId,
data.hashIndex,
&data.pointerData);
}
gotMessage = true;
}
/* If we got any messages, try to release dead messages */
if (gotMessage)
{
SpinAcquire(SInvalLock);
SIDelExpiredDataEntries(shmInvalBuffer);
SpinRelease(SInvalLock);
}
}
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