TODO Items

Bruce Momjian <pgman(at)candle(dot)pha(dot)pa(dot)us> writes:

> TODO item?

On that note several prior conversations I had here ended with WIBNI
conclusions that really ought to be TODO items, in my humble opinion. Two come
to mind off the top of my head resulting in:

. "SELECT * FROM x JOIN y USING (b) WHERE a=?" could use an index on y(a,b)
since for a constant value of "a" the index traversal would be effectively
equivalent just be "b". This could result in an efficient merge join
avoiding an unnecessary sort.

. The semantics for row-value expressions is wrong. (a,b) < (x,y) should be
true if a<x or if a=x and b<y. Currently it expands to a<x and b<y.

. Fix row-value expression handling to not depend on the operator names and
instead use btree access method strategy values instead, allowing row-value
expressions on other operators with <,=,> behaviour (ie btree indexable
behaviour).

. 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).

--
greg