Re: How to interpret this explain analyse? - Mailing list pgsql-performance

From Joost Kraaijeveld
Subject Re: How to interpret this explain analyse?
Date
Msg-id A3D1526C98B7C1409A687E0943EAC41048A15A@obelix.askesis.nl
Whole thread Raw
In response to How to interpret this explain analyse?  ("Joost Kraaijeveld" <J.Kraaijeveld@Askesis.nl>)
List pgsql-performance
Hi Tom,

Tom Lane schreef:
> Well, the planner does put some emphasis on startup time when dealing
> with a DECLARE CURSOR plan; the problem you face is just that that
> correction isn't large enough.  (From memory, I think it optimizes on
> the assumption that 10% of the estimated rows will actually
> be fetched; you evidently want a setting of 1% or even less.)
I wish I had your mnemory ;-) . The tables contain 1.100.000 records by the way  (that is not nearly 10 %, my math is
notthat good)) 


> We once talked about setting up a GUC variable to control the
> percentage of a cursor that is estimated to be fetched:
> http://archives.postgresql.org/pgsql-hackers/2000-10/msg01108.php
> It never got done but that seems like the most reasonable solution to
> me.
If the proposal means that the cursor is not limited to ths limit in the query but is limited to the fetch than I
supportthe proposal. A bit late I presume. 

Groeten,

Joost Kraaijeveld
Askesis B.V.
Molukkenstraat 14
6524NB Nijmegen
tel: 024-3888063 / 06-51855277
fax: 024-3608416
e-mail: J.Kraaijeveld@Askesis.nl
web: www.askesis.nl

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