Maksim Milyutin <maksim.milyu...@tantorlabs.ru> writes: > I've noticed that COALESCE function doesn't converge to argument > expression if it is alone in argument list of COALESCE as part > simplification routine for expressions in planner. This might suppress > further useful transformations when non-strict ops are required from > some expression like converging OUTER JOIN to INNER one with WHERE qual > containing COALESCE over single column from inner side.
Seems like a reasonable idea --- it's probably a rare case, but the check is cheap enough. I'd add some comments though. Please add this to the open commitfest so we don't lose track of it. regards, tom lane