Function RelationMapOidToFilenode

src/backend/utils/cache/relmapper.c:165–204

* RelationMapOidToFilenode * * The raison d' etre ... given a relation OID, look up its filenode. * * Although shared and local relation OIDs should never overlap, the caller * always knows which we need --- so pass that information to avoid useless * searching. * * Returns InvalidOid if the OID is not known (which should never happen, * but the caller is in a better position to report a

 * but the caller is in a better position to report a meaningful error).
 */
Oid
RelationMapOidToFilenode(Oid relationId, bool shared)
{
	const RelMapFile *map;
	int32		i;

	/* If there are active updates, believe those over the main maps */
	if (shared)
	{
		map = &active_shared_updates;
		for (i = 0; i < map->num_mappings; i++)
		{
			if (relationId == map->mappings[i].mapoid)
				return map->mappings[i].mapfilenode;
		}
		map = &shared_map;
		for (i = 0; i < map->num_mappings; i++)
		{
			if (relationId == map->mappings[i].mapoid)
				return map->mappings[i].mapfilenode;
		}
	}
	else
	{
		map = &active_local_updates;
		for (i = 0; i < map->num_mappings; i++)
		{
			if (relationId == map->mappings[i].mapoid)
				return map->mappings[i].mapfilenode;
		}
		map = &local_map;
		for (i = 0; i < map->num_mappings; i++)
		{
			if (relationId == map->mappings[i].mapoid)
				return map->mappings[i].mapfilenode;
		}
	}

	return InvalidOid;
}

/*
 * RelationMapFilenodeToOid