Re: Is sqlplus too slow to unload data?

wangbin_at_start.com.au (wangbin) writes:

> Hi Chris,
>
> I test all settings. Only LINESIZE has improvement, which is huge.
> When I change it to 500, the speed is about 30M/m. However, the
> avarage of the line is about 2100. So I have to increase it to 2500,
> then the speed drops to 11M/m. It appears that it does reach the
> limitation of sqlplus.

Thanks for the feedback.

My seat of the pants guess with LINESIZE would be that 2500 crosses a blocksize boundary somewhere.

Chris

>
> Thanks,
> Bin
>
> Christopher.Jones_at_oracle.comX wrote in message news:<uy9f5292i.fsf_at_oracle.comX>...
> > wangbin_at_start.com.au (wangbin) writes:
> >
> > > Thanks for all reply.
> > >
> > > Sybrand,
> > > The following is my set parameters in sqlplus. The result is the same.
> > > set pages 0;
> > > set lines 10000;
> >
> > If you do end up using SQL*Plus for this task you might want to
> > benchmark these settings as well:
> >
> > SET SERVEROUTPUT OFF
> > SET APPINFO OFF
> > SET DEFINE OFF
> > SET AUTOPRINT OFF
> >
> > Play with SET TAB and SET FLUSH. Tune LONGCHUNKSIZE if LONGS or LOBs
> > are being fetched. Keep LINESIZE as small as possible to avoid extra
> > memory allocations/copying.
> >
> > Chris

-- 
Christopher Jones, Oracle Corporation, Australia.