Re: AW: What does trace event 38022? (Bug 6405967)

From: Greg Rahn <>
Date: Sat, 28 Mar 2009 20:59:34 -0700
Message-ID: <>

On Fri, Mar 27, 2009 at 9:54 AM, Bobak, Mark <>wrote:

> You mention that _COMPLEX_VIEW_MERGING=false also fixes the problem. I
> suspect that setting the event is a more "fine-grained" solution. In other
> words, setting the _COMPLEX_VIEW_MERGING parameter disables all complex view
> merging, whereas setting event 38022 only disables "distinct sort
> elimination at subquery unnest", which I suspect is just one small aspect of
> complex view merging.
> Of course, this stuff is not documented, so, that's pure speculation on my
> part, and could be totally wrong....

This is correct. Frequently developers use events to activate/deactivate parts of the code just for cases like this - when bugs exist. This gives a finer granularity of control than hidden parameters.

Greg Rahn

Received on Sat Mar 28 2009 - 22:59:34 CDT

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