Function RelationGetPartitionKey

src/backend/utils/cache/partcache.c:53–63

* RelationGetPartitionKey -- get partition key, if relation is partitioned * * Note: partition keys are not allowed to change after the partitioned rel * is created. RelationClearRelation knows this and preserves rd_partkey * across relcache rebuilds, as long as the relation is open. Therefore, * even though we hand back a direct pointer into the relcache entry, it's * safe for callers to

 * the relation open.
 */
PartitionKey
RelationGetPartitionKey(Relation rel)
{
	if (rel->rd_rel->relkind != RELKIND_PARTITIONED_TABLE)
		return NULL;

	if (unlikely(rel->rd_partkey == NULL))
		RelationBuildPartitionKey(rel);

	return rel->rd_partkey;
}

/*
 * RelationBuildPartitionKey