RE: redo size and log_checkpoint_interval

Mitchell,

if ur current Log_checkpoint_interval is 2097152 (20 mb) then is ur os block size = 20 mb/2097152 = 10 bytes? look like is ur want to say that Log_checkpoint_interval = 20971520

but Log_checkpoint_interval shld be set ito OS blocks. so if u want to set to 20 mb then assuming ur os block size is 512 bytes then
Log_checkpoint_interval = 40960

Assume this is set to 40960. Oracle continually calculates the address of the redo record that was written 40960 records (OS blocks) ago. In order to satisfy this parameter, the checkpoint position must advance at least as far as this redo record. Should the checkpoint position point to a redo record written earlier than this target position (written over 40960 records before the record at the end of the log), Oracle writes dirty buffers and advances the checkpoint until it points at a redo record written less than 40960 records ago. Should the checkpoint position point to a redo record newer than this target position (written less than 40960 records ago), Oracle does nothing to satisfy this target for it is already satisfied.

-Mandar

> -----Original Message-----
> From: Mitchell [mailto:mitchell_at_comnet.ca]
> Sent: Monday, April 30, 2001 4:10 PM
> To: Multiple recipients of list ORACLE-L
> Subject: redo size and log_checkpoint_interval
>
>
> Dear DBA
>
> I have 130 gb database running on 7/24 basis. redo logfile
> size is 40mb and
> oracle create about most to 400 archivive log. that mean log
> switch happend
> at 3-4 min at peak time.
>
> As oracle suggest, it is better log switch between 30min.
> (Why, if so that
> need more recovery time?)
> If I will increase the size to 100mb and make time around 30
> min. How about
> Log_checkpooint_interval. My currently setting is 2097152 (20mb).
> log_checkpoint_timeout = 0
>
> As my understand, the interval based on volume. If setting is
> 100mb, mean 5
> check point will occured at 20mb interval. I am right?
>
> Any suggest?
>
> Mitchell
>
>
>
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> Please see the official ORACLE-L FAQ: http://www.orafaq.com
> --
> Author: Mitchell
> INET: mitchell_at_comnet.ca
>
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-- 
Please see the official ORACLE-L FAQ: http://www.orafaq.com
-- 
Author: Mandar Ghosalkar
  INET: MandarG_at_gsr-inc.com

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