Re: Tuning direct path read (lob)
Date: Thu, 19 Mar 2009 20:35:59 -0000
Message-ID: <a4ydnfuX_uIzMV_UnZ2dnUVZ8giWnZ2d_at_bt.com>
<matthias.hoys_at_gmail.com> wrote in message
news:13d5ed22-cb86-4c13-a71c-11dc14bc8ade_at_t3g2000yqa.googlegroups.com...
> Hi,
>
> I'm currently investigating a possible performance problem with a
> Oracle 8.1.7 database on Windows XP (I know 8i is out of support, but
> this is an "embedded" database that comes with the application).
>
> A statspack report showed me that the biggest amount of waits were
> related to "direct path read (lob)" events.
> Any idea on how I could tune this event ? I couldn't find much in the
> Oracle docs.
>
> Matthias
It sounds as if you have some lobs declared to be out of line and nocache. Depending on the way you are using the lobs it may help if you cache them. However, since lobs are "large" objects, this could cause havoc in your cache so you may want create a relatively small recycle pool and assign the lobs to it. This gives you the benefit of cached lobs without the threat of flooding your main cache with lob data and kicking everything else out.
-- Regards Jonathan Lewis http://jonathanlewis.wordpress.com Author: Cost Based Oracle: Fundamentals http://www.jlcomp.demon.co.uk/cbo_book/ind_book.html The Co-operative Oracle Users' FAQ http://www.jlcomp.demon.co.uk/faq/ind_faq.htmlReceived on Thu Mar 19 2009 - 15:35:59 CDT