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Clemens Bleile

Technical and non-technical sessions at the DOAG 2018

The amazing DOAG 2018 conference is over now. As every year we saw great technical as well as great non-technical sessions. What impressed me was the non-technical presentation “Zurück an die Arbeit – Wie aus Business-Theatern wieder echte Unternehmen werden” (back to work – how business theatres become real business company again) provided by Lars Vollmer. It was very funny, but also thought-provoking. Lars started with the provocative sentence that people do work too less. Not in terms of time, but in terms of what people do. I.e. lots of things they do looks like work, but actually is not. Like meetings, yearly talks, reports, presentations, etc. At one point Lars started talking about Dabbawalas in India to show that people may work with highest quality and totally independent without any hierarchical structure. It’s a very old concept. As lunch is too expensive in some Indian cities there is a service to bring the lunch in boxes from home to work. The people delivering the lunch boxes work totally independently, they have no boss and often are not able to read. But still, they are able to handover the lunch boxes from Dabbawala to Dabbawala until it finally arrives at the destination. The independent workers provide the service with an unbelievable high quality. I.e. out of 6 million lunch boxes only 1 is not delivered to the correct target. That’s impressive. See e.g. Wikipedia Dabbawala for it.

One of the technical sessions, which I appreciated to be able to attend was about “Oracle’s kernel debug, diagnostics & tracing infrastructure” provided by Stefan Köhler.
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That returned to mind my early days at Oracle Support with statements like


alter system set events '<EVENT_NUMBER> trace name context forever, level <X>';

However, the time of setting numeric events (e.g. 10046) is over as Oracle uses the UTS (Unified Tracing Service) for new events only and already maps some numbers to an Event++.

An example for UTS is:


alter session set events 'trace[RDBMS.SQL_Compiler.*][SQL: 869cv4hgb868z] disk=highest';

I.e. the section within the second brackets is the scope. In the example above that means create a 10053-trace on SQL_ID 869cv4hgb868z once that is parsed.

To make sure that events are populated from the SGA to all sessions PGA, Oracle introduced a new parameter “_evt_system_event_propagation” in 11g. Unfortunately that feature was broken in Oracle 12.2 (bug #25989066 & #25994378) and fixed in Oracle 18c. See also the comments in Blog Enable 10046 tracing for a specific SQL.

It’s sad that the conference DOAG 2018 is over, but we are looking forward to an interesting event in 2019. The world is changing to more Open Source software used in businesses and it will be interesting to see how Oracle (and also the DOAG) will react on that.

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Clemens Bleile
Clemens Bleile

Technology Leader and Senior Consultant