Re: Optimizing fetch of big result set - HELP!

"Colin McKinnon" <colin_at_EditMeOutUnlessYoureABot.wew.co.uk> wrote in message news:<j9gpj9.k6d.ln_at_Lonmay.wew.co.uk>...
> Sybrand Bakker <postbus_at_sybrandb.demon.nl> wrote in message
> news:996080181.15128.0.pluto.d4ee154e_at_news.demon.nl...
> >
> > "Philippe Laflamme" <plaflamme_at_konova.com> wrote in message
> > news:cIC77.22126$eY6.2501085_at_news20.bellglobal.com...
> > > Hello,
> > > Does anyone have any clues as how to optimize fetching of data from a
 result
> > > set on one table?
>
> It's been a while but isn't that what EXPLAIN is there for? - you'll
> probably need to read the manuals for an explanation of EXPLAIN ;)
>
> > 2 make sure your number of records times the number of bytes for a single
> > record does NOT exceed the session data unit of sqlnet, usually 2048
 bytes.
> > If this doesn't work find out what the Max Transmission Unit of your
 network
> > card is (usually 1508 bytes) and lower the session data unit in
 listener.ora
> > and tnsnames.ora to this number.
> > You should avoid segmenting by Oracle or by the TCP/IP protocol at all
> > costs. I have been in a situation where the optimum was to fetch 20
> records,
>
> erm....shouldn't that be:
> 1) usually 1500 bytes on a ethernet interface
> 2) the size of the mtu less the size of the ip packet header (44 bytes seems
> to ring a bell) or a multiple thereof if it is less.
>
> Colin

1. The ethernet MTU seems to vary by O/S. For AIX I'm quite sure it is 1508
2. Running iptrace and ipreport on the connection didn't show any influence of an ip header: all bytes were being used.

Regards,

Sybrand Bakker, Senior Oracle DBA Received on Fri Jul 27 2001 - 09:46:09 CEST