inval.c

PostgreSQL 8.1.4的源码 适用于Linux下的开源数据库系统

PostPrepare_Inval(void)
{
	AtEOXact_Inval(false);
}

/*
 * AtSubStart_Inval
 *		Initialize inval lists at start of a subtransaction.
 */
void
AtSubStart_Inval(void)
{
	TransInvalidationInfo *myInfo;

	Assert(transInvalInfo != NULL);
	myInfo = (TransInvalidationInfo *)
		MemoryContextAllocZero(TopTransactionContext,
							   sizeof(TransInvalidationInfo));
	myInfo->parent = transInvalInfo;
	myInfo->my_level = GetCurrentTransactionNestLevel();
	transInvalInfo = myInfo;
}

/*
 * PersistInvalidationMessage
 *		Write an invalidation message to the 2PC state file.
 */
static void
PersistInvalidationMessage(SharedInvalidationMessage *msg)
{
	RegisterTwoPhaseRecord(TWOPHASE_RM_INVAL_ID, TWOPHASE_INFO_MSG,
						   msg, sizeof(SharedInvalidationMessage));
}

/*
 * inval_twophase_postcommit
 *		Process an invalidation message from the 2PC state file.
 */
void
inval_twophase_postcommit(TransactionId xid, uint16 info,
						  void *recdata, uint32 len)
{
	SharedInvalidationMessage *msg;

	switch (info)
	{
		case TWOPHASE_INFO_MSG:
			msg = (SharedInvalidationMessage *) recdata;
			Assert(len == sizeof(SharedInvalidationMessage));
			SendSharedInvalidMessage(msg);
			break;
		case TWOPHASE_INFO_FILE_BEFORE:
			RelationCacheInitFileInvalidate(true);
			break;
		case TWOPHASE_INFO_FILE_AFTER:
			RelationCacheInitFileInvalidate(false);
			break;
		default:
			Assert(false);
			break;
	}
}


/*
 * AtEOXact_Inval
 *		Process queued-up invalidation messages at end of main transaction.
 *
 * If isCommit, we must send out the messages in our PriorCmdInvalidMsgs list
 * to the shared invalidation message queue.  Note that these will be read
 * not only by other backends, but also by our own backend at the next
 * transaction start (via AcceptInvalidationMessages).	This means that
 * we can skip immediate local processing of anything that's still in
 * CurrentCmdInvalidMsgs, and just send that list out too.
 *
 * If not isCommit, we are aborting, and must locally process the messages
 * in PriorCmdInvalidMsgs.	No messages need be sent to other backends,
 * since they'll not have seen our changed tuples anyway.  We can forget
 * about CurrentCmdInvalidMsgs too, since those changes haven't touched
 * the caches yet.
 *
 * In any case, reset the various lists to empty.  We need not physically
 * free memory here, since TopTransactionContext is about to be emptied
 * anyway.
 *
 * Note:
 *		This should be called as the last step in processing a transaction.
 */
void
AtEOXact_Inval(bool isCommit)
{
	if (isCommit)
	{
		/* Must be at top of stack */
		Assert(transInvalInfo != NULL && transInvalInfo->parent == NULL);

		/*
		 * Relcache init file invalidation requires processing both before and
		 * after we send the SI messages.  However, we need not do anything
		 * unless we committed.
		 */
		if (transInvalInfo->RelcacheInitFileInval)
			RelationCacheInitFileInvalidate(true);

		AppendInvalidationMessages(&transInvalInfo->PriorCmdInvalidMsgs,
								   &transInvalInfo->CurrentCmdInvalidMsgs);

		ProcessInvalidationMessages(&transInvalInfo->PriorCmdInvalidMsgs,
									SendSharedInvalidMessage);

		if (transInvalInfo->RelcacheInitFileInval)
			RelationCacheInitFileInvalidate(false);
	}
	else if (transInvalInfo != NULL)
	{
		/* Must be at top of stack */
		Assert(transInvalInfo->parent == NULL);

		ProcessInvalidationMessages(&transInvalInfo->PriorCmdInvalidMsgs,
									LocalExecuteInvalidationMessage);
	}

	/* Need not free anything explicitly */
	transInvalInfo = NULL;
}

/*
 * AtEOSubXact_Inval
 *		Process queued-up invalidation messages at end of subtransaction.
 *
 * If isCommit, process CurrentCmdInvalidMsgs if any (there probably aren't),
 * and then attach both CurrentCmdInvalidMsgs and PriorCmdInvalidMsgs to the
 * parent's PriorCmdInvalidMsgs list.
 *
 * If not isCommit, we are aborting, and must locally process the messages
 * in PriorCmdInvalidMsgs.	No messages need be sent to other backends.
 * We can forget about CurrentCmdInvalidMsgs too, since those changes haven't
 * touched the caches yet.
 *
 * In any case, pop the transaction stack.	We need not physically free memory
 * here, since CurTransactionContext is about to be emptied anyway
 * (if aborting).  Beware of the possibility of aborting the same nesting
 * level twice, though.
 */
void
AtEOSubXact_Inval(bool isCommit)
{
	int			my_level = GetCurrentTransactionNestLevel();
	TransInvalidationInfo *myInfo = transInvalInfo;

	if (isCommit)
	{
		/* Must be at non-top of stack */
		Assert(myInfo != NULL && myInfo->parent != NULL);
		Assert(myInfo->my_level == my_level);

		/* If CurrentCmdInvalidMsgs still has anything, fix it */
		CommandEndInvalidationMessages();

		/* Pass up my inval messages to parent */
		AppendInvalidationMessages(&myInfo->parent->PriorCmdInvalidMsgs,
								   &myInfo->PriorCmdInvalidMsgs);

		/* Pending relcache inval becomes parent's problem too */
		if (myInfo->RelcacheInitFileInval)
			myInfo->parent->RelcacheInitFileInval = true;

		/* Pop the transaction state stack */
		transInvalInfo = myInfo->parent;

		/* Need not free anything else explicitly */
		pfree(myInfo);
	}
	else if (myInfo != NULL && myInfo->my_level == my_level)
	{
		/* Must be at non-top of stack */
		Assert(myInfo->parent != NULL);

		ProcessInvalidationMessages(&myInfo->PriorCmdInvalidMsgs,
									LocalExecuteInvalidationMessage);

		/* Pop the transaction state stack */
		transInvalInfo = myInfo->parent;

		/* Need not free anything else explicitly */
		pfree(myInfo);
	}
}

/*
 * CommandEndInvalidationMessages
 *		Process queued-up invalidation messages at end of one command
 *		in a transaction.
 *
 * Here, we send no messages to the shared queue, since we don't know yet if
 * we will commit.	We do need to locally process the CurrentCmdInvalidMsgs
 * list, so as to flush our caches of any entries we have outdated in the
 * current command.  We then move the current-cmd list over to become part
 * of the prior-cmds list.
 *
 * Note:
 *		This should be called during CommandCounterIncrement(),
 *		after we have advanced the command ID.
 */
void
CommandEndInvalidationMessages(void)
{
	/*
	 * You might think this shouldn't be called outside any transaction, but
	 * bootstrap does it, and also ABORT issued when not in a transaction. So
	 * just quietly return if no state to work on.
	 */
	if (transInvalInfo == NULL)
		return;

	ProcessInvalidationMessages(&transInvalInfo->CurrentCmdInvalidMsgs,
								LocalExecuteInvalidationMessage);
	AppendInvalidationMessages(&transInvalInfo->PriorCmdInvalidMsgs,
							   &transInvalInfo->CurrentCmdInvalidMsgs);
}

/*
 * CacheInvalidateHeapTuple
 *		Register the given tuple for invalidation at end of command
 *		(ie, current command is creating or outdating this tuple).
 */
void
CacheInvalidateHeapTuple(Relation relation, HeapTuple tuple)
{
	PrepareForTupleInvalidation(relation, tuple);
}

/*
 * CacheInvalidateRelcache
 *		Register invalidation of the specified relation's relcache entry
 *		at end of command.
 *
 * This is used in places that need to force relcache rebuild but aren't
 * changing any of the tuples recognized as contributors to the relcache
 * entry by PrepareForTupleInvalidation.  (An example is dropping an index.)
 * We assume in particular that relfilenode/reltablespace aren't changing
 * (so the rd_node value is still good).
 *
 * XXX most callers of this probably don't need to force an smgr flush.
 */
void
CacheInvalidateRelcache(Relation relation)
{
	Oid			databaseId;
	Oid			relationId;

	relationId = RelationGetRelid(relation);
	if (relation->rd_rel->relisshared)
		databaseId = InvalidOid;
	else
		databaseId = MyDatabaseId;

	RegisterRelcacheInvalidation(databaseId, relationId);
	RegisterSmgrInvalidation(relation->rd_node);
}

/*
 * CacheInvalidateRelcacheByTuple
 *		As above, but relation is identified by passing its pg_class tuple.
 */
void
CacheInvalidateRelcacheByTuple(HeapTuple classTuple)
{
	Form_pg_class classtup = (Form_pg_class) GETSTRUCT(classTuple);
	Oid			databaseId;
	Oid			relationId;
	RelFileNode rnode;

	relationId = HeapTupleGetOid(classTuple);
	if (classtup->relisshared)
		databaseId = InvalidOid;
	else
		databaseId = MyDatabaseId;
	if (classtup->reltablespace)
		rnode.spcNode = classtup->reltablespace;
	else
		rnode.spcNode = MyDatabaseTableSpace;
	rnode.dbNode = databaseId;
	rnode.relNode = classtup->relfilenode;

	RegisterRelcacheInvalidation(databaseId, relationId);
	RegisterSmgrInvalidation(rnode);
}

/*
 * CacheInvalidateRelcacheByRelid
 *		As above, but relation is identified by passing its OID.
 *		This is the least efficient of the three options; use one of
 *		the above routines if you have a Relation or pg_class tuple.
 */
void
CacheInvalidateRelcacheByRelid(Oid relid)
{
	HeapTuple	tup;

	tup = SearchSysCache(RELOID,
						 ObjectIdGetDatum(relid),
						 0, 0, 0);
	if (!HeapTupleIsValid(tup))
		elog(ERROR, "cache lookup failed for relation %u", relid);
	CacheInvalidateRelcacheByTuple(tup);
	ReleaseSysCache(tup);
}

/*
 * CacheRegisterSyscacheCallback
 *		Register the specified function to be called for all future
 *		invalidation events in the specified cache.
 *
 * NOTE: currently, the OID argument to the callback routine is not
 * provided for syscache callbacks; the routine doesn't really get any
 * useful info as to exactly what changed.	It should treat every call
 * as a "cache flush" request.
 */
void
CacheRegisterSyscacheCallback(int cacheid,
							  CacheCallbackFunction func,
							  Datum arg)
{
	if (cache_callback_count >= MAX_CACHE_CALLBACKS)
		elog(FATAL, "out of cache_callback_list slots");

	cache_callback_list[cache_callback_count].id = cacheid;
	cache_callback_list[cache_callback_count].function = func;
	cache_callback_list[cache_callback_count].arg = arg;

	++cache_callback_count;
}

/*
 * CacheRegisterRelcacheCallback
 *		Register the specified function to be called for all future
 *		relcache invalidation events.  The OID of the relation being
 *		invalidated will be passed to the function.
 *
 * NOTE: InvalidOid will be passed if a cache reset request is received.
 * In this case the called routines should flush all cached state.
 */
void
CacheRegisterRelcacheCallback(CacheCallbackFunction func,
							  Datum arg)
{
	if (cache_callback_count >= MAX_CACHE_CALLBACKS)
		elog(FATAL, "out of cache_callback_list slots");

	cache_callback_list[cache_callback_count].id = SHAREDINVALRELCACHE_ID;
	cache_callback_list[cache_callback_count].function = func;
	cache_callback_list[cache_callback_count].arg = arg;

	++cache_callback_count;
}