Tag Archives: trace

SQL*Net message from client on sqlplus?

Posted on May 26, 2014 by Marcel-Jan Krijgsman

Here is a very weird issue I encountered recently. I was working on a test to find out whether different values of parallel parameters would result in better performance for a data warehouse setup. I had noticed that several important SQL … Continue reading →

Posted in Oracle performance tuning | Tagged CPU usage, Oracle performance, parallel execution, PowerCenter, PX servers, resmgr:pq queued, SQL*Net message from client, top, trace | Leave a comment

Useful stuff from event 10053 traces – part 2

Posted on April 18, 2014 by Marcel-Jan Krijgsman

I would like to reflect once more on the “dynamic sampling used for this statement” message. Suppose dynamic sampling really happened with reason, because statistics were old, missing or otherwise insufficient. Now what? Dynamic sampling because of missing or old statistics … Continue reading →

Posted in Oracle performance tuning | Tagged dynamic sampling, event 10053, Oracle performance, Oracle SQL tuning, trace | Leave a comment

Useful stuff from event 10053 traces – part 1

Posted on April 14, 2014 by Marcel-Jan Krijgsman

In theory you can use event 10053 traces to see what choices the optimizer has made, which is very interesting if your query didn’t perform as it was supposed to do. In practice event 10053 traces contain an overwhelming amount … Continue reading →

Posted in Oracle performance tuning | Tagged Beyond Compare, dynamic sampling, event 10053, optimizer, Oracle performance, Oracle SQL tuning, statistics, trace, vimdiff | Leave a comment

Dynamic sampling NOT used for this statement?

Posted on April 8, 2014 by Marcel-Jan Krijgsman

So I’m still working on this data warehousing project and performance is not quite optimal. There are all kinds of things to be investigated. One thing I want to find, is the reason why a lot of execution plans show … Continue reading →

Posted in Oracle performance tuning | Tagged dynamic sampling, event 10053, Oracle performance, Oracle SQL tuning, statistics, trace | Leave a comment

trace_column.sql 1.1

Posted on December 31, 2012 by Marcel-Jan Krijgsman

For a long time, as a DBA, I mostly didn’t have access to tuning tools, like the Diagnostics Pack. Oracle’s Diagnostics Pack is very handy and I’d recommend it to to anyone who has to deal with performance problems in … Continue reading →

Posted in Oracle performance tuning | Tagged event 10046, Oracle performance, trace, trace_column.sql, trace_kolom.sql | Leave a comment