Re: Performance degradation 8.4 -> 9.1 - Mailing list pgsql-general

From Tomas Vondra
Subject Re: Performance degradation 8.4 -> 9.1
Date
Msg-id fd224cbbfa5058d07da935d0a2adc520.squirrel@sq.gransy.com
Whole thread Raw
In response to Re: Performance degradation 8.4 -> 9.1  (Greg Smith <greg@2ndQuadrant.com>)
List pgsql-general
On 18 Listopad 2011, 11:39, Greg Smith wrote:
> On 11/17/2011 02:24 PM, Joseph Shraibman wrote:
>> This query is taking much longer on 9.1 than it did on 8.4.  Why is it
>> using a seq scan?
>>
>
> To answer that question in all cases, it's necessary to know a) the
> query, b) the PostgreSQL version, c) the table definitions including
> what indexes exist, d) the statistics collected about each column, (e)
> the sizes of all the indexes on any referenced table, and (f) the server
> parameters.  Sometimes you can get useful feedback from just the first

And (g) EXPLAIN ANALYZE plans for the queries - if possible from both
versions. Use explain.depesz.com to post it.

Tomas


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