Re: Index usage problem on 8.3.3

From: Jeff Frost <jeff(at)frostconsultingllc(dot)com>
To: Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us>
Cc: pgsql-performance(at)postgresql(dot)org
Subject: Re: Index usage problem on 8.3.3
Date: 2008-10-31 00:52:17
Message-ID: 490A56C1.8020804@frostconsultingllc.com
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Tom Lane wrote:
> Jeff Frost <jeff(at)frostconsultingllc(dot)com> writes:
>
>> I've run across a strange problem with PG 8.3.3 not using indexes on a
>> particular table after building the table during a transaction.
>>
>
> This may be a HOT side-effect ... is pg_index.indcheckxmin set for
> the index?
>
Yep, sure enough, the 'act' table's indexes have it set and jefftest and
jefftest2's indexes do not.

select c.relname,i.indcheckxmin from pg_class c, pg_index i WHERE
i.indexrelid = c.oid AND c.relname IN ('act_act_usr_id', 'act_arrived',
'act_closing', 'act_place');
relname | indcheckxmin
----------------+--------------
act_closing | t
act_act_usr_id | t
act_place | t
act_arrived | t
(4 rows)

consdb=# select c.relname,i.indcheckxmin from pg_class c, pg_index i
WHERE i.indexrelid = c.oid AND c.relname IN
('jefftest2_jefftest_usr_id', 'jefftest2_arrived', 'jefftest2_closing',
'jefftest2_place');
relname | indcheckxmin
---------------------------+--------------
jefftest2_jefftest_usr_id | f
jefftest2_place | f
jefftest2_arrived | f
jefftest2_closing | f
(4 rows)

--
Jeff Frost, Owner <jeff(at)frostconsultingllc(dot)com>
Frost Consulting, LLC http://www.frostconsultingllc.com/
Phone: 916-647-6411 FAX: 916-405-4032

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