Andrey Kriushin wrote:
> Hi, Remigiusz,
>
> Some more ideas to consider:
>
> - if you suspect bad performance of the storage containing your redo
> logs (case B in Cary Millsap's notation), it would be helpful to check
> 'log file parallel writes' wait event. This event is recorded and IO
> time is measured by LGWR itself, so this is reliable source of info at
> first hand. The only problem with this measure is that the IO size may
> vary significantly... Though in your case (frequent commits) that
> would not be the case.
>
> - the problem might also be with OS delays in redo log file opening at
> log switch. Why not to try to help OS and make this process a little
> bit more easy? Steve Adams has a script on his site named
> hold_logs_open.sh. IMHO, it's worth looking at.
>
> - well, you can also turn on LGWR tracing at level 8 to see log switch
> details in the microscope...
>
>
thanks for advice - I've just analyze Your input - probably it will be
the first step we'll try :-)
--
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Remigiusz Sokolowski <rems_at_wp-sa.pl>
WP/PTI/DIP/ZAB (+04858) 52 15 770
MySQL v. 4.x
Oracle v. 10.x
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http://www.freelists.org/webpage/oracle-l
Received on Mon Feb 26 2007 - 02:35:28 CST
