Troubleshooting Another Complex Performance Issue – Oracle direct path inserts and SEG$ contention

Tanel Poder

2015-11-11

Here’s an updated presentation I first delivered at Hotsos Symposium 2015.

It’s about lots of concurrent PX direct path insert ant CTAS statements that, when clashing with another bug/problem, caused various gc buffer busy waits and enq: TX – allocate ITL entry contention. This got amplified thanks to running this concurrent workload on 4 RAC nodes:

When reviewing these slides, I see there’s quite a lot that needs to be said in addition to what’s on slides, so this might just mean a (Powerpoint) hacking session some day!


NB! Check out my 2019 and 2020 online training classes here! Advanced Oracle SQL Tuning training, Practical Linux Performance & Application Troubleshooting training (new), Advanced Oracle Troubleshooting training. In addition to the online classes, all attendees will receive personal downloadable video recordings too!