Bruce Momjian <pgman@candle.pha.pa.us> writes:
> > . Allow multi-column indexes to be used to optimize row-value expressions. Ie,
> > allow a btree index on a,b to be used to execute an expression like (a,b) <
> > (x,y).
>
> I have not heard of any of those so I have not been actively excluding
> them from the TODO list. However, I need someone with optimizer
> experience to make a recommendation.
Well the row-value expression stuff comes out of a discussion just this week.
You could check messages on pgsql-performance with the subject "[PERFORM] best
way to fetch next/prev record based on index". In particular Tom's messages
from Wednesday the 28th might be relevant.
The optimization in the first one came up in a conversation that was quite a
bit older. I don't have that thread saved. It seems like an obvious
optimization if it can be done efficiently.
--
greg