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Re: Memory exeception

From: Peter Wasem <peter(dot)wasem(at)itag(dot)ch>
To: Barry Lind <barry(at)xythos(dot)com>
Cc: pgsql-jdbc(at)postgresql(dot)org
Subject: Re: Memory exeception
Date: 2001-11-08 08:19:16
Message-ID: 3BEA4004.A015A242@itag.ch (view raw or flat)
Thread:
Lists: pgsql-jdbc
Hi Barry

This is exactly what I observed. The physical memory dropped down to almost
zero (but no swap was used) before the exception was thrown. I'm not sure if I
can use cursors (other than ResultSet) since my application is Java-based.

Thanks

Barry Lind wrote:

> Peter,
>
> Postgres will return the entire result into memory first before
> processing the first row of data.  If you don't want this behavior you
> should use explicit cursors and fetch statements to get data a few rows
> at a time.  See the postgres documentation on the 'cursor' and 'fetch'
> sql statements.
>
> thanks,
> --Barry
>
> Peter Wasem wrote:
>
> > Hi
> >
> > I have a problem in processing large numbers of rows in ResultSets.
> > Here's the code fragment where the problem occurs:
> >
> > ...
> >     ResultSet rset = stmt.executeQuery( "select ... from ... where ...
> > order by ..." ) ;
> >     while(rset.next() )
> >     { // Process the row }
> > ...
> >
> > The query addresses some 100'000 rows. When stmt.executeQuery() is
> > executed suddenly an exception occurs.
> > The same program works fine with other JDBC drivers.
> >
> > Any ideas ?
> >
> > Greetings
> > Peter
> >
> > ---------------------------(end of broadcast)---------------------------
> > TIP 2: you can get off all lists at once with the unregister command
> >     (send "unregister YourEmailAddressHere" to majordomo(at)postgresql(dot)org)
> >

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