Re: Redo Copy Latch contention ??

You can still tune the buffers, you just don't need BCHR to do it.

See http://www.ixora.com.au/scripts/sql/ideal_cache_size.sql and http://www.ixora.com.au/newsletter/2001_03.htm

I've procedurized this script to run from dbms_jobs every 15 minutes.

Two reports are used to give current buffer size, ideal buffers average and ideal buffers max.

One does an aggregate of the whole enchilada, the other breaks it down into weekly aggregates.

The whole set of files is at
http://www.cybcon.com/~jkstill/util/zips/idcs.tgz

Jared

Mladen Gogala <mgogala_at_adelphia.net>
Sent by: ml-errors_at_fatcity.com
 07/02/2003 07:50 PM
 Please respond to ORACLE-L  

        To:     Multiple recipients of list ORACLE-L <ORACLE-L_at_fatcity.com>
        cc: 
        Subject:        Re: Redo Copy Latch contention ??

You are probably right but it was good to have V6-type control over the mechanism. log_simultaneous_copies, log_small_entry_max_size (maximum number of characters that was allocated when allocation latch was acquired)
and log_entry_prebuild_threshold (the size of redo after which the user process was building redo entries, instead of LGWR) were easy to understand
and maintain. These days, I have no control. Do you remember X$KCBCH tables
(I'm not sure about the spelling of this one) that was helping you compute

"hit ratio" if there were few more block buffers? World certainly was simpler
before you and Cary destroyed the hit ratio. Shame on you :)!

On 2003.07.02 22:24, Anjo Kolk wrote:
>
> Wrong alert in HP Open view (you can configure that) and (again)
ignoring
> other more relevant performance information ('High CPU usage'). I have
never
> seen a system where tuning the redo copy latches made a huge improvement
in
> performance.
>
> Anjo.

-- 
Mladen Gogala
Oracle DBA
-- 
Please see the official ORACLE-L FAQ: http://www.orafaq.net
-- 
Author: Mladen Gogala
  INET: mgogala_at_adelphia.net

Fat City Network Services    -- 858-538-5051 http://www.fatcity.com
San Diego, California        -- Mailing list and web hosting services
---------------------------------------------------------------------
To REMOVE yourself from this mailing list, send an E-Mail message
to: ListGuru_at_fatcity.com (note EXACT spelling of 'ListGuru') and in
the message BODY, include a line containing: UNSUB ORACLE-L
(or the name of mailing list you want to be removed from).  You may
also send the HELP command for other information (like subscribing).



-- 
Please see the official ORACLE-L FAQ: http://www.orafaq.net
-- 
Author: 
  INET: Jared.Still_at_radisys.com

Fat City Network Services    -- 858-538-5051 http://www.fatcity.com
San Diego, California        -- Mailing list and web hosting services
---------------------------------------------------------------------
To REMOVE yourself from this mailing list, send an E-Mail message
to: ListGuru_at_fatcity.com (note EXACT spelling of 'ListGuru') and in
the message BODY, include a line containing: UNSUB ORACLE-L
(or the name of mailing list you want to be removed from).  You may
also send the HELP command for other information (like subscribing).