Thread: samekeys

I think I have solved the optimizer problem.  It appears in samekeys(). 
Can someone check that function, and see if you come up with the same
fix I do (without knowing my fix)?

A 9-table join that used to run for minutes and fail now completes in
seconds!  I want to commit this, but want confirmation from someone else
that my fix is correct.

--  Bruce Momjian                        |  http://www.op.net/~candle maillist@candle.pha.pa.us            |  (610)
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Bruce Momjian <maillist@candle.pha.pa.us> writes:
> I think I have solved the optimizer problem.  It appears in samekeys(). 
> Can someone check that function, and see if you come up with the same
> fix I do (without knowing my fix)?

"member" -> "equal", perhaps?

I looked at that before and thought it was a little strange, but I
didn't and still don't understand the data structures being compared.

I also wondered whether the two lists ought not be required to be
exactly the same length, rather than allowing keys2 to be longer.


> A 9-table join that used to run for minutes and fail now completes in
> seconds!

Pick some smaller joins and see whether the optimizer still finds
the same answer...
        regards, tom lane