Got it. Here is an updated patch where I added a corresponding comment.
Thank you!
Playing around I found one more place which could easily modified with
hash_seq_init_with_hash_value() call.
--
Teodor Sigaev E-mail: teo...@sigaev.ru
WWW: http://www.sigaev.ru/diff --git a/src/backend/utils/cache/attoptcache.c b/src/backend/utils/cache/attoptcache.c
index af978ccd4b1..28980620662 100644
--- a/src/backend/utils/cache/attoptcache.c
+++ b/src/backend/utils/cache/attoptcache.c
@@ -44,12 +44,10 @@ typedef struct
/*
* InvalidateAttoptCacheCallback
- * Flush all cache entries when pg_attribute is updated.
+ * Flush cache entry (or entries) when pg_attribute is updated.
*
* When pg_attribute is updated, we must flush the cache entry at least
- * for that attribute. Currently, we just flush them all. Since attribute
- * options are not currently used in performance-critical paths (such as
- * query execution), this seems OK.
+ * for that attribute.
*/
static void
InvalidateAttoptCacheCallback(Datum arg, int cacheid, uint32 hashvalue)
@@ -57,7 +55,16 @@ InvalidateAttoptCacheCallback(Datum arg, int cacheid, uint32 hashvalue)
HASH_SEQ_STATUS status;
AttoptCacheEntry *attopt;
- hash_seq_init(&status, AttoptCacheHash);
+ /*
+ * By convection, zero hash value is passed to the callback as a sign
+ * that it's time to invalidate the cache. See sinval.c, inval.c and
+ * InvalidateSystemCachesExtended().
+ */
+ if (hashvalue == 0)
+ hash_seq_init(&status, AttoptCacheHash);
+ else
+ hash_seq_init_with_hash_value(&status, AttoptCacheHash, hashvalue);
+
while ((attopt = (AttoptCacheEntry *) hash_seq_search(&status)) != NULL)
{
if (attopt->opts)
@@ -70,6 +77,17 @@ InvalidateAttoptCacheCallback(Datum arg, int cacheid, uint32 hashvalue)
}
}
+/*
+ * Hash function compatible with two-arg system cache hash function.
+ */
+static uint32
+relatt_cache_syshash(const void *key, Size keysize)
+{
+ const AttoptCacheKey* ckey = key;
+
+ return GetSysCacheHashValue2(ATTNUM, ckey->attrelid, ckey->attnum);
+}
+
/*
* InitializeAttoptCache
* Initialize the attribute options cache.
@@ -82,9 +100,17 @@ InitializeAttoptCache(void)
/* Initialize the hash table. */
ctl.keysize = sizeof(AttoptCacheKey);
ctl.entrysize = sizeof(AttoptCacheEntry);
+
+ /*
+ * AttoptCacheEntry takes hash value from the system cache. For
+ * AttoptCacheHash we use the same hash in order to speedup search by hash
+ * value. This is used by hash_seq_init_with_hash_value().
+ */
+ ctl.hash = relatt_cache_syshash;
+
AttoptCacheHash =
hash_create("Attopt cache", 256, &ctl,
- HASH_ELEM | HASH_BLOBS);
+ HASH_ELEM | HASH_FUNCTION);
/* Make sure we've initialized CacheMemoryContext. */
if (!CacheMemoryContext)
