Re: Considering fractional paths in Append node

On 11/2/24 01:18, Nikita Malakhov wrote:
> I've corrected failing test and created a patch at Commitfest:
> https://commitfest.postgresql.org/51/5361/ <https:// 
> commitfest.postgresql.org/51/5361/>
I have played around with this feature, which looks promising for such a 
tiny change. It provides a 'bottom boundary' recommendation for 
appending subpaths, participating in the 'fractional branch' of paths.
As I see it works consistently with the plans, created for plain tables 
filled with similar data.
According to the proposal to change SeqScan logic, IMO, Andy is right. 
But it is a separate improvement because it wouldn't work in the case of 
LIMIT 10 or 100, as the newly added regression tests demonstrate.
I think this feature gives sensible profit for partitionwise paths. 
Pushing this knowledge into subpaths could help postgres_fdw to reduce 
network traffic.

-- 
regards, Andrei Lepikhov