Function ENRMetadataGetTupDesc

src/backend/utils/misc/queryenvironment.c:232–252

* Gets the TupleDesc for a Ephemeral Named Relation, based on which field was * filled. * * When the TupleDesc is based on a relation from the catalogs, we count on * that relation being used at the same time, so that appropriate locks will * already be held. Locking here would be too late anyway. */

 * already be held.  Locking here would be too late anyway.
 */
TupleDesc
ENRMetadataGetTupDesc(EphemeralNamedRelationMetadata enrmd)
{
	TupleDesc	tupdesc;

	/* not only one, but use reliddesc field first. */
	Assert(enrmd->reliddesc || enrmd->tupdesc);

	if (enrmd->tupdesc != NULL)
		tupdesc = enrmd->tupdesc;
	else
	{
		Relation	relation;

		relation = table_open(enrmd->reliddesc, NoLock);
		tupdesc = relation->rd_att;
		table_close(relation, NoLock);
	}

	return tupdesc;
}