Afternoon,
in my experience, at least since 9.2, ANSI syntax and old style is
mostly the same explain plan. I believe that at 9.1 there were bugs that
causes ANSI code to be dramatically more inefficient that the old style
joins, but since 9.2 that has all gone away.
I have been using ANSI joins for a while, whenever I can, and I see no
performance differences.
What sort of troubles are you seeing with the code you are looking at?
Is there actually a performance problem or is it a perceived one?
Have you tried running the code with 10046 level 8 or 12 trace running,
or DBMS_SUPPORT.START_TRACE_IN_SESSION and looking in the trace file -
the STAT lines will show you the actual plan that Oracle used whereas,
explain plan shows you the plan Oracle might use - they can be
different.
Having said that, no one has ever given me a good reason why they might
be different!
Cheers,
Norm. [TeamT]
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