Drilling Deep Into Exadata Performance with ASH, SQL Monitoring and Exadata Snapper – slides and a hacking session!

Tanel Poder


The promised hacking session about Exadata performance troubleshooting will happen on Thursday 21st February 9am-11am PST (2 hours). I will show a number of examples and demos where the Exadata Snapper shows what was going on in storage cells when running Smart Scans or just doing IO.

Register here (free stuff!):


I will post the scripts on the day of this session.

Note that you should read through the slides before the hacking session – as I’m not going to spend much time on presenting slides, as the name says – it’s a hacking session, so 95% demos. I will show a couple of important slides which explain the essence of Exadata Snapper (check slide 17, 21, 22), but otherwise it’s all demos.

This hacking session will also give a little preview of what’s going to happen in my new Advanced Exadata Performance seminars – see below ;-) As far as I know, there is no other seminar in the world (well at least available to public) where you can learn so deep knowledge about Exadata performance troubleshooting, optimization and internals – all arranged around a systematic approach for dealing with Exadata performance issues.

New Seminar – Advanced Exadata Performance: Troubleshooting and Optimization

This advanced seminar is meant for DBAs and developers who already have at least the basic experience of working with Exadata and have seen some of the common performance problems that may occur in production or performance tests. In this class we will dive deep into details of how Exadata works internally and then how to systematically troubleshoot performance problems caused either by application, database, storage cell software or Exadata hardware issues. The demos and troubleshooting examples are shown on Enkitec’s in-house Exadata X2-2 and V2 machines and we will use both standard Oracle tools and advanced Exadata troubleshooting scripts written by Tanel.

What students will learn:

What this class is not:


Day 1 – Exadata Internals, Systematic Troubleshooting and Smart Scans

    • Understanding the low-level internals of Exadata data flow all the way from cell disks to the database nodes – and the physics behind its performance
    • Using basic performance tools like V$SQLSTATS, ASH and SQL Monitoring views on Exadata
    • Troubleshooting why Smart Scans (and direct path reads) do not get used
    • Measuring the efficiency of Smart Scans and how much work gets offloaded to the storage cells
    • Troubleshooting advanced Smart Scan performance problems, like passthrough mode and selective fallback to block IO – with Exadata Snapper
    • Using CELLCLI and cell-level metrics where database & session metrics aren’t enough
Day 2 – Parallel Execution, Hybrid Columnar Compression and OLTP

    • PX issues, including the In-Memory Parallel Execution feature
    • Optimizing hash joins for efficient bloom filtering in the cells
    • Troubleshooting Exadata Hybrid Columnar Compression issues
    • Troubleshooting long commit and disk write latency issues on Exadata
    • Troubleshooting flash caching issues and optimizing for tiered caching
    • Learn to use the Exadata scripts, tools and OS commands Tanel regularly uses for Exadata performance troubleshooting
    • Q&A and free-form demo session and/or reviewing Exadata performance case studies

If you like this – check out my Oracle training and seminars page, the first sessions happen already in May! (And there’s even one on-site in Enkitec office in Irving, TX).