Hi, We just upgraded Best Practical's RT from 3.6 to 3.81 and gave the database completely own machine. And the users still complain that it is dog slow. :-( I installed pg_top and it seems that at the beginning of the ticket display RT-issues a query that eats everything the database has. Query is as follows: SELECT DISTINCT main.* FROM Users main CROSS JOIN ACL ACL_2 JOIN Principals Principals_1 ON ( Principals_1.id = main.id ) JOIN CachedGroupMembers CachedGroupMembers_3 ON ( CachedGroupMembers_3.MemberId = Principals_1.id ) WHERE (Principals_1.Disabled = '0') AND (ACL_2.PrincipalId = CachedGroupMembers_3.GroupId) AND (Principals_1.id != '1') AND (ACL_2.PrincipalType = 'Group') AND (Principals_1.PrincipalType = 'User') AND (ACL_2.RightName = 'OwnTicket') AND ((ACL_2.ObjectType = 'RT::Queue' AND ACL_2.ObjectId = 18) OR (ACL_2.ObjectType = 'RT::System')) ORDER BY main.Name ASC and explain tells me that: -> Nested Loop (cost=16.17..9953.51 rows=1 width=4318) Join Filter: ("outer".principalid = "inner".groupid) -> Index Scan using acl1 on acl acl_2 (cost=0.00..49.38 rows=1 width=4) Index Cond: ((principaltype)::text = 'Group'::text) Filter: ((((rightname)::text = 'OwnTicket'::text) OR ((rightname)::text = 'SuperUser'::text)) AND (((objecttype)::text = 'RT::Queue'::text) OR ((objecttype)::text = 'RT::System'::text))) -> Nested Loop (cost=16.17..9903.98 rows=12 width=4322) -> Nested Loop (cost=0.00..6343.98 rows=1 width=4322) -> Seq Scan on principals principals_1 (cost=0.00..6308.00 rows=6 width=4) Filter: ((disabled = 0) AND (id <> 1) AND ((principaltype)::text = 'User'::text)) -> Index Scan using users_pkey on users main (cost=0.00..5.98 rows=1 width=4318) Index Cond: ("outer".id = main.id) -> Bitmap Heap Scan on cachedgroupmembers cachedgroupmembers_3 (cost=16.17..3527.23 rows=2621 width=8) Recheck Cond: (cachedgroupmembers_3.memberid = "outer".id) -> Bitmap Index Scan on cachedgroupmembers2 (cost=0.00..16.17 rows=2621 width=0) Index Cond: (cachedgroupmembers_3.memberid = "outer".id) Is there something I can do to improve performance with tuning something on postgresql.conf? Or adding/dropping indexes? What I read from that query plan is that the single most expensive thing is sequential scan on Principals. Principals already has indexes for both id and object.id! Database version: Name : postgresql-server Relocations: (not relocatable) Version : 8.1.11 Vendor: CentOS Release : 1.el5_1.1 Build Date: Sat 12 Jan 2008 04:45:09 PM EET pg_top: last pid: 7201; load avg: 0.62, 0.90, 0.62; up 0+19:17:00 11:28:10 13 processes: 1 running, 12 sleeping CPU states: 8.2% user, 0.0% nice, 42.4% system, 49.5% idle, 0.0% iowait Memory: 1083M used, 2722M free, 234M buffers, 759M cached Swap: 1024M free PID USERNAME PRI NICE SIZE RES STATE TIME WCPU CPU COMMAND 6015 postgres 17 0 22M 12M run 0:32 13.28% 99.82% postgres: rt rt 6018 postgres 15 0 22M 12M sleep 3:25 0.01% 0.00% postgres: rt rt 6035 postgres 15 0 22M 12M sleep 2:11 1.31% 0.00% postgres: rt rt 6037 postgres 15 0 22M 12M sleep 1:33 0.01% 0.00% postgres: rt rt