Example #1
0
/*
 * Make sure that CommitTs has room for a newly-allocated XID.
 *
 * NB: this is called while holding XidGenLock.  We want it to be very fast
 * most of the time; even when it's not so fast, no actual I/O need happen
 * unless we're forced to write out a dirty CommitTs or xlog page to make room
 * in shared memory.
 *
 * NB: the current implementation relies on track_commit_timestamp being
 * PGC_POSTMASTER.
 */
void
ExtendCommitTs(TransactionId newestXact)
{
	int			pageno;

	/*
	 * Nothing to do if module not enabled.  Note we do an unlocked read of
	 * the flag here, which is okay because this routine is only called from
	 * GetNewTransactionId, which is never called in a standby.
	 */
	Assert(!InRecovery);
	if (!commitTsShared->commitTsActive)
		return;

	/*
	 * No work except at first XID of a page.  But beware: just after
	 * wraparound, the first XID of page zero is FirstNormalTransactionId.
	 */
	if (TransactionIdToCTsEntry(newestXact) != 0 &&
		!TransactionIdEquals(newestXact, FirstNormalTransactionId))
		return;

	pageno = TransactionIdToCTsPage(newestXact);

	LWLockAcquire(CommitTsControlLock, LW_EXCLUSIVE);

	/* Zero the page and make an XLOG entry about it */
	ZeroCommitTsPage(pageno, !InRecovery);

	LWLockRelease(CommitTsControlLock);
}
Example #2
0
/*
 * Sets the commit timestamp of a single transaction.
 *
 * Must be called with CommitTsControlLock held
 */
static void
TransactionIdSetCommitTs(TransactionId xid, TimestampTz ts,
						 RepOriginId nodeid, int slotno)
{
	int			entryno = TransactionIdToCTsEntry(xid);
	CommitTimestampEntry entry;

	Assert(TransactionIdIsNormal(xid));

	entry.time = ts;
	entry.nodeid = nodeid;

	memcpy(CommitTsCtl->shared->page_buffer[slotno] +
		   SizeOfCommitTimestampEntry * entryno,
		   &entry, SizeOfCommitTimestampEntry);
}
Example #3
0
/*
 * Interrogate the commit timestamp of a transaction.
 *
 * The return value indicates whether a commit timestamp record was found for
 * the given xid.  The timestamp value is returned in *ts (which may not be
 * null), and the origin node for the Xid is returned in *nodeid, if it's not
 * null.
 */
bool
TransactionIdGetCommitTsData(TransactionId xid, TimestampTz *ts,
							 RepOriginId *nodeid)
{
	int			pageno = TransactionIdToCTsPage(xid);
	int			entryno = TransactionIdToCTsEntry(xid);
	int			slotno;
	CommitTimestampEntry entry;
	TransactionId oldestCommitTsXid;
	TransactionId newestCommitTsXid;

	if (!TransactionIdIsValid(xid))
		ereport(ERROR,
				(errcode(ERRCODE_INVALID_PARAMETER_VALUE),
		errmsg("cannot retrieve commit timestamp for transaction %u", xid)));
	else if (!TransactionIdIsNormal(xid))
	{
		/* frozen and bootstrap xids are always committed far in the past */
		*ts = 0;
		if (nodeid)
			*nodeid = 0;
		return false;
	}

	LWLockAcquire(CommitTsLock, LW_SHARED);

	/* Error if module not enabled */
	if (!commitTsShared->commitTsActive)
		error_commit_ts_disabled();

	/*
	 * If we're asked for the cached value, return that.  Otherwise, fall
	 * through to read from SLRU.
	 */
	if (commitTsShared->xidLastCommit == xid)
	{
		*ts = commitTsShared->dataLastCommit.time;
		if (nodeid)
			*nodeid = commitTsShared->dataLastCommit.nodeid;

		LWLockRelease(CommitTsLock);
		return *ts != 0;
	}

	oldestCommitTsXid = ShmemVariableCache->oldestCommitTsXid;
	newestCommitTsXid = ShmemVariableCache->newestCommitTsXid;
	/* neither is invalid, or both are */
	Assert(TransactionIdIsValid(oldestCommitTsXid) == TransactionIdIsValid(newestCommitTsXid));
	LWLockRelease(CommitTsLock);

	/*
	 * Return empty if the requested value is outside our valid range.
	 */
	if (!TransactionIdIsValid(oldestCommitTsXid) ||
		TransactionIdPrecedes(xid, oldestCommitTsXid) ||
		TransactionIdPrecedes(newestCommitTsXid, xid))
	{
		*ts = 0;
		if (nodeid)
			*nodeid = InvalidRepOriginId;
		return false;
	}

	/* lock is acquired by SimpleLruReadPage_ReadOnly */
	slotno = SimpleLruReadPage_ReadOnly(CommitTsCtl, pageno, xid);
	memcpy(&entry,
		   CommitTsCtl->shared->page_buffer[slotno] +
		   SizeOfCommitTimestampEntry * entryno,
		   SizeOfCommitTimestampEntry);

	*ts = entry.time;
	if (nodeid)
		*nodeid = entry.nodeid;

	LWLockRelease(CommitTsControlLock);
	return *ts != 0;
}
Example #4
0
/*
 * Interrogate the commit timestamp of a transaction.
 *
 * The return value indicates whether a commit timestamp record was found for
 * the given xid.  The timestamp value is returned in *ts (which may not be
 * null), and the origin node for the Xid is returned in *nodeid, if it's not
 * null.
 */
bool
TransactionIdGetCommitTsData(TransactionId xid, TimestampTz *ts,
							 RepOriginId *nodeid)
{
	int			pageno = TransactionIdToCTsPage(xid);
	int			entryno = TransactionIdToCTsEntry(xid);
	int			slotno;
	CommitTimestampEntry entry;
	TransactionId oldestCommitTs;
	TransactionId newestCommitTs;

	/* error if the given Xid doesn't normally commit */
	if (!TransactionIdIsNormal(xid))
		ereport(ERROR,
				(errcode(ERRCODE_INVALID_PARAMETER_VALUE),
		errmsg("cannot retrieve commit timestamp for transaction %u", xid)));

	LWLockAcquire(CommitTsLock, LW_SHARED);

	/* Error if module not enabled */
	if (!commitTsShared->commitTsActive)
		ereport(ERROR,
				(errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE),
				 errmsg("could not get commit timestamp data"),
			  errhint("Make sure the configuration parameter \"%s\" is set.",
					  "track_commit_timestamp")));

	/*
	 * If we're asked for the cached value, return that.  Otherwise, fall
	 * through to read from SLRU.
	 */
	if (commitTsShared->xidLastCommit == xid)
	{
		*ts = commitTsShared->dataLastCommit.time;
		if (nodeid)
			*nodeid = commitTsShared->dataLastCommit.nodeid;

		LWLockRelease(CommitTsLock);
		return *ts != 0;
	}

	oldestCommitTs = ShmemVariableCache->oldestCommitTs;
	newestCommitTs = ShmemVariableCache->newestCommitTs;
	/* neither is invalid, or both are */
	Assert(TransactionIdIsValid(oldestCommitTs) == TransactionIdIsValid(newestCommitTs));
	LWLockRelease(CommitTsLock);

	/*
	 * Return empty if the requested value is outside our valid range.
	 */
	if (!TransactionIdIsValid(oldestCommitTs) ||
		TransactionIdPrecedes(xid, oldestCommitTs) ||
		TransactionIdPrecedes(newestCommitTs, xid))
	{
		*ts = 0;
		if (nodeid)
			*nodeid = InvalidRepOriginId;
		return false;
	}

	/* lock is acquired by SimpleLruReadPage_ReadOnly */
	slotno = SimpleLruReadPage_ReadOnly(CommitTsCtl, pageno, xid);
	memcpy(&entry,
		   CommitTsCtl->shared->page_buffer[slotno] +
		   SizeOfCommitTimestampEntry * entryno,
		   SizeOfCommitTimestampEntry);

	*ts = entry.time;
	if (nodeid)
		*nodeid = entry.nodeid;

	LWLockRelease(CommitTsControlLock);
	return *ts != 0;
}