Re: Wierd Explain - Mailing list pgsql-general

From Martijn van Oosterhout
Subject Re: Wierd Explain
Date
Msg-id 20020618183425.B2786@svana.org
Whole thread Raw
In response to Re: Wierd Explain  (Varun Kacholia <varunk@cse.iitb.ac.in>)
List pgsql-general
On Tue, Jun 18, 2002 at 12:33:26PM +0530, Varun Kacholia wrote:
> hi ,
>   Many ppl have suggested me vaccum analyze .
>   But the manuals say me that it is reqd after "major update/deletion".
>   I have just 'created' the tables and done fresh insertions.
>   is it still required?
>   BTW i am using 7.1.3 ... seems it does not support analyze :(.

Fresh inserts would count as "major" since now there are values and before
there wern't :).

Anyway, a vacuum analyze is recommended anything you think the planner is
doing something wrong. Prior to 7.2 you could only do the analyze with a
vacuum, in 7.2 it was separated out

Also, EXPLAIN VERBOSE could be helpful also.

> On Mon, Jun 17, 2002 at 11:17:06PM +0200, Jochem van Dieten wrote:
> > Varun Kacholia wrote:
> > > hi ,
> > >  I have just migrated to PostgreSQL...and found the following wierd :
> > >
> > >  suryadb=# explain select * from dbwin where id in (select id from wdwin
> > >  where word='bacd');
> > >  NOTICE:  QUERY PLAN:
> > >  Seq Scan on dbwin  (cost=0.00..8158.20 rows=1000 width=76)
> >
> > 1000 rows should trigger the obvious question: did I run vacuum analyze?
> >
> > Jochem

--
Martijn van Oosterhout   <kleptog@svana.org>   http://svana.org/kleptog/
> There are 10 kinds of people in the world, those that can do binary
> arithmetic and those that can't.

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