Arjen van der Meijden <[EMAIL PROTECTED]> writes:
> Anyway, I was looking into the usefullness of a INSERT INTO newtable 
> SELECT field, field, CASE pkey WHEN x1 THEN y1 WHEN x2 THEN y2 etc END 
> FROM oldtable

> The resulting select was about 1.7MB of query-text, mostly composed of 
> the CASE-statement.

Hm, you mean one single SELECT, one single CASE?  How many WHEN clauses
exactly?  Exactly what did a typical clause of the CASE look like?

I wouldn't be too surprised to find some bit of code that's O(N^2) in
the number of arms of the CASE, or something like that; it's not an area
that we've ever felt the need to optimize.  But I'd like a fairly
specific test case before trying to look into it.

                        regards, tom lane

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TIP 9: the planner will ignore your desire to choose an index scan if your
      joining column's datatypes do not match

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