David Griffiths wrote:

It's a slight improvement, but that could be other things as well.

I'd read that how you tune Postgres will determine how the optimizer works
on a query (sequential scan vs index scan). I am going to post all I've done
with tuning tommorow, and see if I've done anything dumb. I've found some
contradictory advice, and I'm still a bit hazy on how/why Postgres trusts
the OS to do caching. I'll post it all tommorow.

----------------------------------------------------------------------------
----------------------------------------------------------------------------
----------------
 Merge Join  (cost=11819.21..15258.55 rows=12007 width=752) (actual
time=4107.64..5587.81 rows=20880 loops=1)
   Merge Cond: ("outer".commercial_entity_id = "inner".commercial_entity_id)
   ->  Index Scan using comm_serv_comm_ent_id_i on commercial_service cs
(cost=0.00..3015.53 rows=88038 width=12) (actual time=0.05..487.23
rows=88038 loops=1)
   ->  Sort  (cost=11819.21..11846.08 rows=10752 width=740) (actual
time=3509.07..3955.15 rows=25098 loops=1)
         Sort Key: ce.commercial_entity_id

I think this is the problem. Is there an index on ce.commercial_entity_id?


         ->  Merge Join  (cost=0.00..9065.23 rows=10752 width=740) (actual
time=0.18..2762.13 rows=7990 loops=1)
               Merge Cond: ("outer".user_account_id =
"inner".user_account_id)
               ->  Index Scan using user_account_pkey on user_account
(cost=0.00..8010.39 rows=72483 width=716) (actual time=0.05..2220.86
rows=72483 loops=1)
               ->  Index Scan using comm_ent_usr_acc_id_i on
commercial_entity ce  (cost=0.00..4787.69 rows=78834 width=24) (actual
time=0.02..55.64 rows=7991 loops=1)

In this case of comparing account ids, its using two index scans. In the entity field though, it chooses a sort. I think there is an index missing. The costs are also shot up as well.


Total runtime: 226239.77 msec

Standard performance question. What was the last time these tables/database were vacuumed. Have you tuned postgresql.conf correctly?


HTH

Shridhar


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