Josh,
I declared all the indexes that you suggested and ran vacuum full
analyze. The query plan has not changed and it's still trying to use
seqscan. I tried to disable seqscan, but the plan didn't change. Any
other suggestions?
I started explain analyze on the query, but I doubt it will finish any
time soon.
Thanks.
Oleg
-----Original Message-----
From: Josh Berkus [mailto:josh@agliodbs.com]
Sent: Thursday, October 02, 2003 11:27 PM
To: Oleg Lebedev; scott.marlowe
Cc: pgsql-performance@postgresql.org
Subject: Re: [PERFORM] TPC-R benchmarks
Oleg,
> I have another question. How do I optimize my indexes for the query
> that contains a lot of ORed blocks, each of which contains a bunch of
> ANDed expressions? The structure of each ORed block is the same except
> the right-hand-side values vary.
Given the example, I'd do a multicolumn index on p_brand, p_container,
p_size
and a second multicolumn index on l_partkey, l_quantity, l_shipmode.
Hmmm
... or maybe seperate indexes, one on l_partkey and one on l_quantity,
l_shipmode & l_instruct. Test both configurations.
Mind you, if this is also an OLTP table, then you'd want to test those
multi-column indexes to determine the least columns you need for the
indexes
still to be used, since more columns = more index maintainence.
--
Josh Berkus
Aglio Database Solutions
San Francisco
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