On Thu, Nov 11, 2004 at 10:24:34 -0500, Tom Lane <[EMAIL PROTECTED]> wrote: > > We know how to determine that an index matches an ORDER BY clause. > But what has an aggregate called MAX() got to do with ORDER BY? Magic > assumptions about operators named "<" are not acceptable answers; there > has to be a traceable connection in the catalogs. > > As a real-world example of why I won't hold still for hard-wiring this: > a complex-number data type might have btree opclasses allowing it to be > sorted either by real part or by absolute value. One might then define > max_real() and max_abs() aggregates on the type. It should be possible > to optimize such aggregates the same way as any other max() aggregate.
Wouldn't knowing an opclass and direction associated with an aggregrate function allow you to do this? ---------------------------(end of broadcast)--------------------------- TIP 4: Don't 'kill -9' the postmaster
