Function GetSysCacheHashValue

src/backend/utils/cache/syscache.c:1651–1663

* GetSysCacheHashValue * * Get the hash value that would be used for a tuple in the specified cache * with the given search keys. * * The reason for exposing this as part of the API is that the hash value is * exposed in cache invalidation operations, so there are places outside the * catcache code that need to be able to compute the hash values. */

 * catcache code that need to be able to compute the hash values.
 */
uint32
GetSysCacheHashValue(int cacheId,
					 Datum key1,
					 Datum key2,
					 Datum key3,
					 Datum key4)
{
	if (cacheId < 0 || cacheId >= SysCacheSize ||
		!PointerIsValid(SysCache[cacheId]))
		elog(ERROR, "invalid cache ID: %d", cacheId);

	return GetCatCacheHashValue(SysCache[cacheId], key1, key2, key3, key4);
}

/*
 * List-search interface