[livejournal] r23562: LJSUP-14875: [internal] add "use index" ...

[vadvs]

Committer: vadLJSUP-14875: [internal] add "use index" hint to query back to query since dbs still have performance issues

U trunk/cgi-bin/LJ/Event.pm

Modified: trunk/cgi-bin/LJ/Event.pm
===================================================================
--- trunk/cgi-bin/LJ/Event.pm 2013-01-18 09:19:36 UTC (rev 23561)
+++ trunk/cgi-bin/LJ/Event.pm 2013-01-18 12:52:37 UTC (rev 23562)
@@ -689,11 +689,14 @@
# FIXME: journals are only on one cluster! split jidlist based on cluster
my $jidlist = join(",", @wildcards_from);

+ ## Strictly specify USE INDEX(PRIMARY) hint.
+ ## Otherwise mysql query planner is acting out and query takes inexcusable amount of time.
my $sth = $udbh->prepare(qq{
SELECT
userid, subid, is_dirty, journalid, etypeid,
arg1, arg2, ntypeid, createtime, expiretime, flags
FROM subs
+ USE INDEX(PRIMARY)
WHERE etypeid=? AND journalid=0 $and_enabled
AND userid IN ($jidlist)
});