On Wed, Oct 9, 2024 at 4:19 AM David Rowley <dgrowle...@gmail.com> wrote: > On Wed, 9 Oct 2024 at 20:07, Shayon Mukherjee <shay...@gmail.com> wrote: > > [thinking…] Unless - we try to do support both a GUC and the ALTER INDEX > > ENABLE/DISABLE grammar + isdisabled attribute on pg_index? > > I just wanted to explain my point of view on this. This is my opinion > and is by no means authoritative. > > I was interested in this patch when you proposed it as an ALTER INDEX > option. I know other committers seem interested, but I personally > don't have any interest in the GUC option. I think the reason I > dislike it is that it's yet another not even half-baked take on > planner hints (the other one being enable* GUCs). I often thought that > if we ever did planner hints that it would be great to have multiple > ways to specify the hints. Ordinarily, I'd expect some special comment > type as the primary method to specify hints, but equally, it would be > nice to be able to specify them in other ways. e.g. a GUC to have them > apply to more than just 1 query. Useful for things such as "don't use > index X".
+1. A GUC can be done as a contrib module using existing hooks, and I think that's already been done outside of core, perhaps multiple times. That certainly doesn't mean we CAN'T add it as an in-core feature, but I do think "yet another not even half-baked take on planner hints" is a fair description. What I would personally like to see is for us to ship one or possibly more than one contrib module that let people do hint-like things in useful ways, and this could be a part of that. But I think we need better infrastructure for controlling the planner behavior first, hence the "allowing extensions to control planner behavior" thread. -- Robert Haas EDB: http://www.enterprisedb.com
