Hi Jeff >Could someone give me some "benchmarks" defining good performance? Performance is good when end-user expectations are met. >What is a good benchmark for determining if a query is doing too many >buffer reads, or too many disk reads? Is 10,000 buffer reads considered >high, or is it 1,000,000? Or does it matter if, on the overall, things >kick butt. It really depends... eventually even 1 LIO is too much. This is the case = when it is not necessary to run the query! Personally I usually give a look to the number of LIO per row. If this = value is smaller than 5 it is usually ok, if it is larger than 20 it is = normally bad. Everything in between should be analyzed. >This is a half hour window during peak usage. Is anything way off? More information is needed... e.g. how many CPU has your system? HTH Chris -- //www.freelists.org/webpage/oracle-l