Does the application *need* to be committing as often as it does? Cary Millsap Method R Corporation http://method-r.com http://carymillsap.blogspot.com http://twitter.com/cary_millsap On Thu, May 28, 2009 at 8:55 AM, Ujang Jaenudin <ujang.jaenudin@xxxxxxxxx>wrote: > bobak, > > log file sync is the main reason. > _log_io_size is 0 (default??) > > strength on my db when user session only 200 but log file sync can > reach 800 session waitings (from dbconsole). when checking the io log > file parallel write max is 4ms, but log file sync can reach 22ms. > > average redo blocks per write is 13 which means average buffer to > write to redolog buffer is only 6656 nytes. > > yes the application is heavily commit activites (now in the "load > testing" stage) > > any direction why too many spikes (strange) on log file sync? > > -- > thanks and regards > ujang | oracle dba | mysql dba > http://ora62.wordpress.com > > > On Thu, May 28, 2009 at 8:49 PM, Bobak, Mark <Mark.Bobak@xxxxxxxxxxxx> > wrote: > > Ok, first, take a step back. > > > > What is motivating you to look at log_buffer in the first place? Why do > you think it needs to be adjusted? Starting w/ 10g, the log_buffer is > maintained by Oracle, and should not need to be adjusted. (See MetaLink Doc > ID 351857.1.) What is the current value of _log_io_size? Why do you think > you need to adjust it? > > > > Main question: > > What is it that is leading you to believe that log_buffer and > _log_io_size need to be adjusted? > > > > -Mark > > > > -----Original Message----- > > From: oracle-l-bounce@xxxxxxxxxxxxx [mailto: > oracle-l-bounce@xxxxxxxxxxxxx] On Behalf Of Ujang Jaenudin > > Sent: Thursday, May 28, 2009 6:14 AM > > To: Oracle Discussion List > > Subject: log_buffer 10gr2 > > > > dear all, > > > > I have 10.2.0.3 on solaris sparc, > > when trying to decrease log_buffer, it could not be done. > > > > always keep 14MB, sga is 3.5GB > > I want to decrease it to 1MB > > > > according to metalink note. 351857.1 > > it is expected behavior. > > > > so, is it save to change _log_io_size to 1MB ? > > > > > > -- > > thanks and regards > > ujang | oracle dba | mysql dba > > http://ora62.wordpress.com > > -- > > //www.freelists.org/webpage/oracle-l > > > > > > > > > > > -- > //www.freelists.org/webpage/oracle-l > > >