George Dunlap writes ("Re: [OSSTEST PATCH 06/14] sg-report-flight: Use WITH clause to use index for $anypassq"): > > On Jul 21, 2020, at 7:41 PM, Ian Jackson <ian.jack...@eu.citrix.com> wrote: > > + # In psql 9.6 this WITH clause makes postgresql do the steps query > > + # first. This is good because if this test never passed we can > > + # determine that really quickly using the new index, without > > + # having to scan the flights table. (If the test passed we will > > + # probably not have to look at many flights to find one, so in > > + # that case this is not much worse.) > > Seems a bit weird, but OK. The SQL looks the same, so: > > Reviewed-by: George Dunlap <george.dun...@citrix.com>
Thanks. This business with the WITH clause as an optimisation fence is well-known in Postgres circles, it seems. Ian.