Adaptive STAT lines in SQL trace

Lately I’ve been using SQL runtime execution statistics combined with SQL monitor for performance diagnostics and, honestly, almost forgot about SQL trace. So this note is not very useful to me but it might be to someone: along with ALL_EXECUTIONS option appeared in (I believe) 11gR2, there’s a new option starting with 11.2.0.2 which can significantly decrease amount of data in the trace files for STAT lines compared to ALL_EXECUTIONS, still providing some of them from time to time.

Scalar subquery unnesting

Here is a nice example of what Oracle 11.2.0.2 is able to do with a subquery inside an expression. It can unnest it – that is a new 11.2.0.2 feature of the transformation part of the CBO.

Is this really a patch set?

The title of the post is a question taken from a MOS Doc ID 1189783.1 named “Important Changes to Oracle Database Patch Sets Starting With 11.2.0.2”. Yes, the first patch set for 11gR2 is out for Linux x86 and x86-64 (patch number is 10098816). It’s 5G in size, BTW. There’s no patch set release notes, though. I’ll update the post when they become available.

Update 11-SEP: the patch is no longer available for downloading.
Update 13-SEP: the patch is now available.
Update 16-SEP: patch set release notes are now available