Oracle FAQ Your Portal to the Oracle Knowledge Grid
HOME | ASK QUESTION | ADD INFO | SEARCH | E-MAIL US
 

Home -> Community -> Mailing Lists -> Oracle-L -> Re: v$sql 'db block changes'

Re: v$sql 'db block changes'

From: Tanel Põder <tanel.poder.003_at_mail.ee>
Date: Thu, 15 Dec 2005 15:01:59 -0600
Message-ID: <019301c601ba$d191b590$8ebc21c8@porgand>


Selects can cause write activity, both for sorting/hashing into temp tablespace also for delayed block cleanout (which is written to disk by dbwr in background).

Which version are you on? From 9i you could use v$segment_statistics to get some understanding for which segments most of the writes are done.

Also query v$session_event for all those sessions and make sure that foreground direct writes (or direct lob writes) arent prevalent there.

Tanel.

> If only it were that easy. The problem here is that the application uses
> connection pooling, so there is no single session responsible for the
> heavy updates - it bounces around amongst 40 different sessions. The top
> statements in v$sql in terms of cpu, elapsed_time, buffer_gets and
> disk_reads are all SELECT statements, so I know they're not causing the
> write activity.
>
> Thanks,
> Brandon

--
http://www.freelists.org/webpage/oracle-l
Received on Thu Dec 15 2005 - 15:02:28 CST

Original text of this message

HOME | ASK QUESTION | ADD INFO | SEARCH | E-MAIL US