Function pg_sequence_last_value

src/backend/commands/sequence.c:2035–2068

* Return the last value from the sequence * * Note: This has a completely different meaning than lastval(). */

 * Note: This has a completely different meaning than lastval().
 */
Datum
pg_sequence_last_value(PG_FUNCTION_ARGS)
{
	Oid			relid = PG_GETARG_OID(0);
	SeqTable	elm;
	Relation	seqrel;
	Buffer		buf;
	HeapTupleData seqtuple;
	Form_pg_sequence_data seq;
	bool		is_called;
	int64		result;

	/* open and lock sequence */
	init_sequence(relid, &elm, &seqrel);

	if (pg_class_aclcheck(relid, GetUserId(), ACL_SELECT | ACL_USAGE) != ACLCHECK_OK)
		ereport(ERROR,
				(errcode(ERRCODE_INSUFFICIENT_PRIVILEGE),
				 errmsg("permission denied for sequence %s",
						RelationGetRelationName(seqrel))));

	seq = read_seq_tuple(seqrel, &buf, &seqtuple);

	is_called = seq->is_called;
	result = seq->last_value;

	UnlockReleaseBuffer(buf);
	relation_close(seqrel, NoLock);

	if (is_called)
		PG_RETURN_INT64(result);
	else
		PG_RETURN_NULL();
}


void