Function RelationGetIndexAttOptions

src/backend/utils/cache/relcache.c:5944–5991

* RelationGetIndexAttOptions * get AM/opclass-specific options for an index parsed into a binary form */

 *		get AM/opclass-specific options for an index parsed into a binary form
 */
bytea	  **
RelationGetIndexAttOptions(Relation relation, bool copy)
{
	MemoryContext oldcxt;
	bytea	  **opts = relation->rd_opcoptions;
	Oid			relid = RelationGetRelid(relation);
	int			natts = RelationGetNumberOfAttributes(relation);	/* XXX
																	 * IndexRelationGetNumberOfKeyAttributes */
	int			i;

	/* Try to copy cached options. */
	if (opts)
		return copy ? CopyIndexAttOptions(opts, natts) : opts;

	/* Get and parse opclass options. */
	opts = palloc0(sizeof(*opts) * natts);

	for (i = 0; i < natts; i++)
	{
		if (criticalRelcachesBuilt && relid != AttributeRelidNumIndexId)
		{
			Datum		attoptions = get_attoptions(relid, i + 1);

			opts[i] = index_opclass_options(relation, i + 1, attoptions, false);

			if (attoptions != (Datum) 0)
				pfree(DatumGetPointer(attoptions));
		}
	}

	/* Copy parsed options to the cache. */
	oldcxt = MemoryContextSwitchTo(relation->rd_indexcxt);
	relation->rd_opcoptions = CopyIndexAttOptions(opts, natts);
	MemoryContextSwitchTo(oldcxt);

	if (copy)
		return opts;

	for (i = 0; i < natts; i++)
	{
		if (opts[i])
			pfree(opts[i]);
	}

	pfree(opts);

	return relation->rd_opcoptions;
}

/*
 * Routines to support ereport() reports of relation-related errors