Re: setFetchSize [Viruschecked] - Mailing list pgsql-jdbc

This is actually pretty nice... but I need a solution for today. Summing it all up, today I have to use cursors,
right?
  Better yet, I think I'll patch my jdbc driver to use cursors when I specify a fetch size :-)

On Thu, 17 Jul 2003 18:28:06 -0700
Barry Lind <blind@xythos.com> wrote:

>
>
> Felipe Schnack wrote:
> >   Hi Patric!
> >   hm... would be nice if this patch of yours were in the current driver... you submitted it to the maintainers?
> >   I actually don't understand why the default behaviour is to fetch all data, seems crazy to me :-)
> >
>
> In 7.4 the protocol that clients use to talk with the server has changed
> to allow much more efficient fetching of data.  One of the reasons this
> was changed was because of feedback from the jdbc driver developers.  So
> in the future this will work much better than today.  Unfortunately it
> will take time before all of the new features in the V3 protocol are
> utilized by the jdbc code.  But it is now possible to do a much better job.
>
> thanks,
> --Barry
>
>
>
> > On Thu, 17 Jul 2003 16:12:32 +0200
> > "Patric Bechtel" <bechtel@ipcon.de> wrote:
> >
> >
> >>-----BEGIN PGP SIGNED MESSAGE-----
> >>Hash: SHA1
> >>
> >>On Thu, 17 Jul 2003 09:31:45 -0400, Fernando Nasser wrote:
> >>
> >>
> >>>Felipe Schnack wrote:
> >>>
> >>>>  There is a way that I can set setFetchSize() that will prevent pgsql from caching all the results of a query to
server'smemory? 
> >>>>  I'm trying to search in the archives but any search I try returns 0 results...
> >>>>
> >>
> >>>Have you tried setting it to a positive value and turning off autocommit
> >>>(you must be inside a transaction to do this)?
> >>
> >>Hello Felipe,
> >>
> >>nice to see that there's another one who has the same problem than me (although if would be nicer if we both
wouldn't;-)). 
> >>I've an application using Castor (maybe hibernate, in a later version), but SOME queries tend to produce huge
resultsets, as though directly after transferring to  
> >>the 'client' (which in this case is the app server), can be forgotten at all. But postgres seems to hold this query
inone of the front ends, though. This happens  
> >>in the moment I use setFetchSize() (I've a patched postgres driver which can do this via the URL), the server
startseating memory like nuts. 
> >>In one case, a rather trivial query with very many rows even broke the backend completely, as after 1.5 GB there
wasno RAM available anymore. It looked like This  
> >>one backend process which grew then is not shrinking anymore (at least no significantly), and I can only get rid of
itby closing the connection; this one isn't  
> >>trivial, as I'm using a connection pool.
> >>But I need the connection pool, as without this, Castor as well as Hibernate are incredibly slow; for each
transactionthey open a connection, do what ever is  
> >>needed, commit or rollback, and close the connection. And even IF they wouldn't, it would be a problem, though.
> >>Is there anything one can do to use server side cursors AND having the postgres server using a reasonable amount of
memory?
> >>BTW: I can reproduce this behaviour in psql, too, so it's not really a problem of the JDBC driver itself. But I've
foundno discussion on GENERAL of HACKERS about  
> >>that, too.
> >>
> >>tia
> >>
> >>Patric
> >>
> >>PGP Public Key Fingerprint: 2636 F26E F523 7D62  4377 D206 7C68 06BB
> >>
> >>-----BEGIN PGP SIGNATURE-----
> >>Version: PGPsdk version 1.7.1 (C) 1997-1999 Network Associates, Inc. and its affiliated companies.
> >>
> >>iQA/AwUBPxagwXxoBrvMu8qQEQJsjwCdE1e3GHFgBGZegw9w0bfxrgjDrPcAn1yV
> >>Xt75aWxAuBqDijvPET2v2v4b
> >>=1OFf
> >>-----END PGP SIGNATURE-----
> >>
> >>
> >>
> >>---------------------------(end of broadcast)---------------------------
> >>TIP 6: Have you searched our list archives?
> >>
> >>               http://archives.postgresql.org
> >
> >
> >
>
>
>


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