On Mon, Jun 18, 2018 at 3:12 PM, Tom Lane <t...@sss.pgh.pa.us> wrote: > Perhaps there are use-cases where you want globally visible effects, > but the primary use-case Andrew cited (i.e. EXPLAIN experimentation) > would not want that. > > Anyway, if we do it with a GUC, the user can control the scope of > the effects.
I had imagined that those use cases would be the most common. Dropping an index in production because it very much looks like it is unused is always a bit nerve-wracking in my experience. It's often hard to be 100% sure due to factors like replicas, the possible loss of statistic collector stats masking a problem, the possibility that there are very important queries that do use the index but are only run very infrequently, and so on. -- Peter Geoghegan
