Thread: Grouping sets

Hello

I got a possibility to continue on GROUPING SETS see
http://wiki.postgresql.org/wiki/Grouping_Sets

My last patch was based on an sharing functionality with non recursive
CTE. I would to recapitulate all options here and I would to prepare
this patch for next commitfest.

a) using actualised patch - review:
http://archives.postgresql.org/message-id/162867790811240316y52227d88xe53527399b329e05@mail.gmail.com + it is simple
(sharelot of code) + it is near to natural implementation - result is in "good" order + allows full implementation of
ANSISQL syntax - GROUP BY
 
[>>ALL<<|DISTINCT] GROUPING SETS(.. - is serial - I read some objections - "it is only syntactic sugar"

b) modification of a (directly using tuple store without CTE code) + add some new code - it isn't syntactic sugar

c) go back to my first patch and use "feeders" - add some complexity to GROUP BY planner ( :-( ) +/- add new concept to
PostgreSQL- semi parallel execution - when datatype isn't hashable, then have to use serial processing - have to solve
somecorner behave of our hashtable support - should be very fast
 

I still prefer option a (with some cleaning)

I invite any comments and helpers.

Regards
Pavel Stehule