Re: No Index-Only Scan on Partial Index

On Oct 3, 2013, at 10:50 AM, Josh Berkus <josh@agliodbs.com> wrote:

>>
>> But anyway, I still don’t understand why, if the function used to store the value is immutable (as upper_inf() is),
whyPostgres doesn't do an index scan. Is this something that could be improved in the planner? 
>
> Yes.  This is clearly a TODO.

Added it here:
 https://wiki.postgresql.org/wiki/Todo#Optimizer_.2F_Executor

Teach the planner how to better use partial indexes for index-only scans•
http://www.postgresql.org/message-id/25141.1345072858@sss.pgh.pa.us•
http://www.postgresql.org/message-id/79C7D74D-59B0-4D97-A5E5-55553EF299AA@justatheory.com

Best,

David