Posts Tagged ‘tuning’

Oracle Trace Analyzer is TKPROF on Steroids

When you generate a raw Oracle SQL Trace file you are faced with the arduous task of analyzing this trace file. Of course, TKPROF has always been there to help you with this analysis. This post is not about TKPROF, it is about another, lesser known, utility called Trace Analyzer, that is everything TKPROF is […]

How do you use tkprof to solve a performance problem?

In his latest article, Jonathan Lewis uses tkprof to analyse the performance of a query. He concluded that “When you examine the output from tkprof, it often takes a simultaneous cross-check of the block level statistics, the Row Source Operation counts, and some sensible guesswork about the purpose of the query, to be able to […]

Oracle SQL tip

While reading Mark Gurry’s OOW05 presentation (PDF), I noticed a simple yet an effective way to tune a query. Here is an example that demonstrates the trick.

What is the COST?

If you use the Cost Based Optimizer (CBO) in your Oracle database, you may be surprised to know that decreasing the ‘COST’ of a query does not necessarily mean increased performance.