Hi Greg, I meant to ask previously, but didn't. Are there any changes to system stat calculation for exadata? You earlier talked about getting stats representative, I wonder (in the absence of an exadata play box), how representative the system stat IO and CPU costing is in this environment? On 13 Sep 2010 17:49, "Greg Rahn" <greg@xxxxxxxxxxxxxxxxxx> wrote: Pavel- This is actually a poor recommendation. Using a "estimate_percent=>null" will be very very costly and since the OP is on 11g (11.2 in fact as he is on Exadata V2), the default value for estimate_percent of dbms_stats.auto_sample_size is much faster and usually within >99% accuracy of a 100% sample. More details on why: http://structureddata.org/2007/09/17/oracle-11g-enhancements-to-dbms_stats/ On Mon, Sep 13, 2010 at 6:14 AM, Pavel Ermakov <ocp.pauler@xxxxxxxxx> wrote: > > Hi > > Try to ga... -- Regards, Greg Rahn http://structureddata.org