Matteo Beccati <[EMAIL PROTECTED]> writes:
> The correct strategy IMHO would 
> be applying the order by and limit for each child table (which results 
> in an index scan, if possible), appending, then finally sorting a bunch 
> of rows, and limiting again.

This would be a win in some cases, and in many others a loss (ie, wasted
sort steps).  The hard part is determining when to apply it.

                        regards, tom lane

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