RE: shared_io_pool

From: Jorgensen, Finn <Finn.Jorgensen_at_constellation.com>
Date: Wed, 10 Apr 2013 15:19:54 -0400
Message-ID: <9CE162BC5ED2C643956B526A7EDE46FF0390A726C671_at_EXM-OMF-04.Ceg.Corp.Net>



I had a lot of issues with this pool when I first started using LOBs in 11.2.0.1. At that time there was a bug in 11.2.0.1 and 11.2.0.2 where this pool could (and would) grow to unlimited size. A one-off patch was released for 11.2.0.2 and included in 11.2.0.3 which limits this pool to 512MB.

As explained by another lister it's used for securefile LOBs. It would appear the pool is allocated even if you don't have any securefile LOBs. Have you checked that no SYSTEM LOB's are securefile? Default setting for db_securefile in 11.2 is PERMITTED so you might have some even if you don't know about it. Check DBA_LOBS view.

Thanks,
Finn

-----Original Message-----
From: oracle-l-bounce_at_freelists.org [mailto:oracle-l-bounce_at_freelists.org] On Behalf Of Petr Novak Sent: Wednesday, April 10, 2013 4:54 AM
To: oracle-l_at_freelists.org
Subject: shared_io_pool

Hallo ,

after upgrade from 10G to 11.2.0.3 DB allocated 430M of shared_io_pool

 select
   ksppinm,
   ksppstvl,
   ksppstdvl
from

   x$ksppcv a,
   x$ksppi b
where

   a.indx=b.indx
and

   b.ksppinm like '%shared_io%';

KSPPINM                        KSPPSTVL             KSPPSTDVL
------------------------------ -------------------- ---------------

__shared_io_pool_size 452984832 432M
_shared_io_pool_size 0 0
_shared_iop_max_size 536870912 512M
_shared_io_pool_buf_size 1048576 1M
_shared_io_pool_debug_trc 0 0
_shared_io_set_value FALSE FALSE

What possibilities are to set upper boundary of shared_io_pool ? With setting _shared_iop_max_size ? Did anybody play with these parameters ? How it is possible to monitor if (and how effective, impact on performance ) this pool is used ? Why the DB allocated such pool ? We have other 11G DBs , also with LOBs , where such pool ist not present.

Best Regards,
Petr--
http://www.freelists.org/webpage/oracle-l

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Received on Wed Apr 10 2013 - 21:19:54 CEST

Original text of this message