Search Results for: v$sesstat

Oracle hidden costs revealed, Part2 – Using DTrace to find why writes in SYSTEM tablespace are slower than in others

I have written two posts in one, about a performance issue with writes in system tablespace and introduction of a little DTrace stack sampling script. Have you noticed that DML on tables residing in SYSTEM tablespace is slower than tables … Continue reading

Posted in Oracle | Tagged , , , , | 27 Comments

Advanced Oracle Troubleshooting Guide, Part 8: Even more detailed latch troubleshooting using LatchProfX

In my last AOT post I published my LatchProf script which is able to sample detailed latchholder data from V$LATCHHOLDER. Latchprof allows you to drill down into your latching problems at session level (which V$LATCH, V$LATCH_PARENT and V$LATCH_CHILDREN can’t do). … Continue reading

Posted in Cool stuff, Oracle | Tagged , , , | 11 Comments

Oracle Troubleshooting with Snapper – detecting who’s causing excessive redo generation

Update: As this post was written many years ago, you should check out newer Snapper articles/videos: My friend asked today a question that how to identify why his Oracle 9.2 database has suddenly started generating loads more redo than … Continue reading

Posted in Oracle | Tagged , | 16 Comments

Oracle hidden costs revealed, part 1 – Does a batch job run faster when executed locally?

This series is about revealing some Oracle’s internal execution costs and inefficiencies. I will analyze few situations and special cases where you can experience a performance hit where you normally wouldn’t expect to. The first topic is about a question … Continue reading

Posted in Uncategorized | Tagged , , , | 11 Comments