That's a really straightforward patch that looks pretty safe, I may play around with that a bit.
Thanks, Tim On Mon, Sep 28, 2020 at 5:45 PM Matthew Bellew <matth...@labkey.com> wrote: > Here is a commit that accomplishes this with a configuration parameter. > > > https://github.com/labkey-matthewb/postgres/commit/b1fd99f4deffbbf3db2172ccaba51a34f18d1b1a > > On Mon, Sep 28, 2020 at 2:07 PM Tom Lane <t...@sss.pgh.pa.us> wrote: > >> Timothy Garnett <tgarn...@panjiva.com> writes: >> > Is there some way to tell the planner that unless it's guaranteed by a >> > constraint or some such it shouldn't guess that the selectivity of a >> > filter/anti-join is 1 row (e.g. minimum to consider is 2 rows unless >> it's >> > guaranteed to be 1 row) or somehow otherwise make it more conservative >> > around the worst case possibilities. >> >> There's been some discussion in that area, but it's a hard problem >> to solve in general, and especially so if you'd like to not break >> a ton of queries that work nicely today. >> >> regards, tom lane >> >> >>
