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
