On 10/13/14, 8:28 PM, Tom Lane wrote:
Jim Nasby <jim.na...@bluetreble.com> writes:
CacheInvalidateHeapTuple currently does the following tests first; would there
be a performance improvement to testing the system relation case first? We're
almost never in bootstrap mode, so that test is almost always a waste. Is there
any reason not to switch the two?
/* Do nothing during bootstrap */
if (IsBootstrapProcessingMode())
return;
/*
* We only need to worry about invalidation for tuples that are in
system
* relations; user-relation tuples are never in catcaches and can't
affect
* the relcache either.
*/
if (!IsSystemRelation(relation))
return;
You're assuming that IsSystemRelation() is safe to apply during bootstrap
mode. Even if it is, I don't see the point of messing with this.
IsBootstrapProcessingMode() is a macro expanding to one comparison
instruction.
Comment patch to that effect attached.
--
Jim Nasby, Data Architect, Blue Treble Consulting
Data in Trouble? Get it in Treble! http://BlueTreble.com
diff --git a/src/backend/utils/cache/inval.c b/src/backend/utils/cache/inval.c
index a7a768e..545ccc5 100644
--- a/src/backend/utils/cache/inval.c
+++ b/src/backend/utils/cache/inval.c
@@ -1055,7 +1055,11 @@ CacheInvalidateHeapTuple(Relation relation,
Oid databaseId;
Oid relationId;
- /* Do nothing during bootstrap */
+ /*
+ * Do nothing during bootstrap. It may seem silly to check this first since
+ * it will almost always be false, but it's not safe to assume that later
+ * checks can be done safely while in bootstrap.
+ */
if (IsBootstrapProcessingMode())
return;
--
Sent via pgsql-hackers mailing list (pgsql-hackers@postgresql.org)
To make changes to your subscription:
http://www.postgresql.org/mailpref/pgsql-hackers
