[postgis-users] && operator memory leak

[Mark Cave-Ayland]

> -----Original Message-----
> From: postgis-users-bounces at postgis.refractions.net 
> [mailto:postgis-users-bounces at postgis.refractions.net] On 
> Behalf Of Carl Anderson
> Sent: 08 March 2004 02:27
> To: postgis-users at postgis.refractions.net
> Subject: [postgis-users] && operator memory leak
> 
> 
> 
> Is anyone actively working on the memory leak in the gist && 
> operator. Or can anyone give me a heads up start point?
> 
> I have had enough of partitioning queries to work around an out ouf  
> memory condition and willing to delve into this issue.
> 
> the issue manifests most simply with a gist index on the_geom 
> for both  
> tables and
> 
> select 1 from mytab
>    where
>      exists ( select 1
>                 from othertab
>                   where othertab.the_geom && mytab.the_geom
>             );
> 
> with
>    mytab ~ 100 thousand tuples
> and
>    othertab ~ 1 million tuples
> 
> much more than 3Gb of real memory is required during the query.
> 
> my datasets have much more than 1 million tuples.
> 
> C.


Hi Carl,

Please can you give us some more information? In particular we would
need the versions of PostgreSQL, PostGIS that you are using, plus the
EXPLAIN ANALYZE output of both:

select 1 from othertab where othertab.the_geom && mytab.the_geom

AND

select 1 from mytab where exists 
	(select 1 from othertab where othertab.the_geom &&
mytab.the_geom)


(NOTE: If the memory leak prevents an EXPLAIN ANALYZE from running the
second query then just an EXPLAIN will hopefully get things moving in
the right direction)


Cheers,

Mark.

---

Mark Cave-Ayland
Webbased Ltd.
Tamar Science Park
Derriford
Plymouth
PL6 8BX
England

Tel: +44 (0)1752 764445
Fax: +44 (0)1752 764446


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