Function IndexSupportInitialize

src/backend/utils/cache/relcache.c:1641–1670

* IndexSupportInitialize * Initializes an index's cached opclass information, * given the index's pg_index.indclass entry. * * Data is returned into *indexSupport, *opFamily, and *opcInType, * which are arrays allocated by the caller. * * The caller also passes maxSupportNumber and maxAttributeNumber, since these * indicate the size of the arrays it has allocated --- but in practice thes

 * for the index and access method.
 */
static void
IndexSupportInitialize(oidvector *indclass,
					   RegProcedure *indexSupport,
					   Oid *opFamily,
					   Oid *opcInType,
					   StrategyNumber maxSupportNumber,
					   AttrNumber maxAttributeNumber)
{
	int			attIndex;

	for (attIndex = 0; attIndex < maxAttributeNumber; attIndex++)
	{
		OpClassCacheEnt *opcentry;

		if (!OidIsValid(indclass->values[attIndex]))
			elog(ERROR, "bogus pg_index tuple");

		/* look up the info for this opclass, using a cache */
		opcentry = LookupOpclassInfo(indclass->values[attIndex],
									 maxSupportNumber);

		/* copy cached data into relcache entry */
		opFamily[attIndex] = opcentry->opcfamily;
		opcInType[attIndex] = opcentry->opcintype;
		if (maxSupportNumber > 0)
			memcpy(&indexSupport[attIndex * maxSupportNumber],
				   opcentry->supportProcs,
				   maxSupportNumber * sizeof(RegProcedure));
	}
}

/*
 * LookupOpclassInfo