Function ExecOpenScanRelation

src/backend/executor/execUtils.c:776–798

---------------------------------------------------------------- * ExecOpenScanRelation * * Open the heap relation to be scanned by a base-level scan plan node. * This should be called during the node's ExecInit routine. * ---------------------------------------------------------------- */

 * ----------------------------------------------------------------
 */
Relation
ExecOpenScanRelation(EState *estate, Index scanrelid, int eflags)
{
	Relation	rel;

	/* Open the relation. */
	rel = ExecGetRangeTableRelation(estate, scanrelid);

	/*
	 * Complain if we're attempting a scan of an unscannable relation, except
	 * when the query won't actually be run.  This is a slightly klugy place
	 * to do this, perhaps, but there is no better place.
	 */
	if ((eflags & (EXEC_FLAG_EXPLAIN_ONLY | EXEC_FLAG_WITH_NO_DATA)) == 0 &&
		!RelationIsScannable(rel))
		ereport(ERROR,
				(errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE),
				 errmsg("materialized view \"%s\" has not been populated",
						RelationGetRelationName(rel)),
				 errhint("Use the REFRESH MATERIALIZED VIEW command.")));

	return rel;
}

/*
 * ExecInitRangeTable