Peter Geoghegan <pg@bowt.ie> writes:
> On Mon, Jun 18, 2018 at 2:57 PM, Tom Lane <tgl@sss.pgh.pa.us> wrote:
>> I think the actually desirable way to handle this sort of thing is through
>> an "index advisor" sort of plugin, which can hide a given index from the
>> planner without any globally visible side-effects.
> The globally visible side-effects are the point, though. Some users
> desire cheap insurance against dropping what turns out to be the wrong
> index.
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.
regards, tom lane