I have seen as small as 2 ms, rarely about 10 ms. Did you check and see if the DBFMBRC might be set too high? On Wed, Sep 24, 2008 at 11:17 AM, Daniel Fink <daniel.fink@xxxxxxxxxxxxxx>wrote: > In a recent optimization effort, I found what I think are high physical > read times. For example, a single block read was averaging 11 milliseconds > with a max of over 1 second (tkprof output). For this session, single block > reads consumed over 80% of the response time, so this is of concern. > > We are running Oracle 10gr1 on AIX with an IBM storage array (shared > amongst many servers). I suspect there is some optimization that can be done > at the storage array level. If 11 milliseconds is well above average, this > will help in engaging that team in the process. > > For those of you running statspack. AWR or other monitoring tools, what are > the average single block read times you are encountering on a good system? > If you are running on an IBM storage array, have you found any specific > issues/fixes? > > Regards, > Daniel Fink > > -- > Daniel Fink > > OptimalDBA.com - Oracle Performance, Diagnosis, Data Recovery and Training > > OptimalDBA http://www.optimaldba.com > Oracle Blog http://optimaldba.blogspot.com > > Lost Data? http://www.ora600.be/ > > -- > //www.freelists.org/webpage/oracle-l > > > -- Andrew W. Kerber 'If at first you dont succeed, dont take up skydiving.'