Re: Allow WindowFuncs prosupport function to use more optimal WindowClause options

On 10/12/22 04:40, David Rowley wrote:
> I've not really done any analysis into which other window functions
> can use this optimisation. The attached only adds support to
> row_number()'s support function and only converts exactly "RANGE
> UNBOUNDED PRECEDING AND CURRENT ROW" into "ROW UNBOUNDED PRECEDING AND
> CURRENT ROW".  That might need to be relaxed a little, but I've done
> no analysis to find that out. 

Per spec, the ROW_NUMBER() window function is not even allowed to have a 
frame specified.

     b) The window framing clause of WDX shall not be present.

Also, the specification for ROW_NUMBER() is:

     f) ROW_NUMBER() OVER WNS is equivalent to the <window function>:

         COUNT (*) OVER (WNS1 ROWS UNBOUNDED PRECEDING)


So I don't think we need to test for anything at all and can 
indiscriminately add or replace the frame with ROWS UNBOUNDED PRECEDING.
-- 
Vik Fearing