Root Cause Analysis (star_transformation_enabled) revisited.

 A couple of weeks ago I posted regarding a performance problem we had run into that was solved by setting STAR_TRANSFORMATION_ENABLED to 'true'. My boss was pushing for a root cause analysis report and I was asking for comment on what I could look at. Several of you replied and affirmed what I felt to be true -- that some unknown and unknowable threshold had been crossed in the size of one or more tables. I'm appreciative of all the input.

Now I am putting the finishing touches on my report, and I can see what will happen next. The question will be posed as to why we don't just set STAR_TRANSFORMATION_ENABLED=true on *all* databases -- just set it and forget it. At this point I really don't have an answer for that. In fact, I wondered earlier myself that if it was such a good idea, why wasn't that just the default anyway?

So, knowing everything is a trade-off . . . what is the potential downside of setting it to true? Especially in non-DW apps? None of the reading I've done so far has talked about trade-offs, just what the parm *does* -- allows the CBO to *consider* . . .

Comments about management intelligence are always enjoyabley entertaining, but I can't put those in my report. (At least not until I'm a lot closer to retirement! I'm sure many of you can identify with that!) So . . . I'm particularly interested in the technical considerations. Received on Thu May 15 2003 - 15:02:25 CDT