Function RehashCatCache

src/backend/utils/cache/catcache.c:860–893

* Enlarge a catcache, doubling the number of buckets. */

 * Enlarge a catcache, doubling the number of buckets.
 */
static void
RehashCatCache(CatCache *cp)
{
	dlist_head *newbucket;
	int			newnbuckets;
	int			i;

	elog(DEBUG1, "rehashing catalog cache id %d for %s; %d tups, %d buckets",
		 cp->id, cp->cc_relname, cp->cc_ntup, cp->cc_nbuckets);

	/* Allocate a new, larger, hash table. */
	newnbuckets = cp->cc_nbuckets * 2;
	newbucket = (dlist_head *) MemoryContextAllocZero(CacheMemoryContext, newnbuckets * sizeof(dlist_head));

	/* Move all entries from old hash table to new. */
	for (i = 0; i < cp->cc_nbuckets; i++)
	{
		dlist_mutable_iter iter;

		dlist_foreach_modify(iter, &cp->cc_bucket[i])
		{
			CatCTup    *ct = dlist_container(CatCTup, cache_elem, iter.cur);
			int			hashIndex = HASH_INDEX(ct->hash_value, newnbuckets);

			dlist_delete(iter.cur);
			dlist_push_head(&newbucket[hashIndex], &ct->cache_elem);
		}
	}

	/* Switch to the new array. */
	pfree(cp->cc_bucket);
	cp->cc_nbuckets = newnbuckets;
	cp->cc_bucket = newbucket;
}

/*
 *		CatalogCacheInitializeCache