Re: Memory exeception - Mailing list pgsql-jdbc

From Nick Fankhauser
Subject Re: Memory exeception
Date
Msg-id NEBBLAAHGLEEPCGOBHDGIEFDDOAA.nickf@ontko.com
Whole thread Raw
In response to Re: Memory exeception  (Peter Wasem <peter.wasem@itag.ch>)
List pgsql-jdbc
Is it possible to take this approach with a query that has an "order by" in
it?

-Nick

> -----Original Message-----

> 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)---------------------------
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> > >
>


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