po 6. 1. 2020 v 13:17 odesílatel Dean Rasheed <dean.a.rash...@gmail.com> napsal:
> On Mon, 6 Jan 2020 at 11:01, Tomas Vondra <tomas.von...@2ndquadrant.com> > wrote: > > > > On Mon, Jan 06, 2020 at 01:04:15PM +0800, 曾文旌(义从) wrote: > > > > >2 We feel that gtt needs to maintain statistics, but there is no > > >agreement on what it will be done. > > > > > > > I certainly agree GTT needs to maintain statistics, otherwise it'll lead > > to poor query plans. > > +1 > > > AFAIK the current patch stores the info in a hash > > table in a backend private memory, and I don't see how else to do that > > (e.g. storing it in a catalog would cause catalog bloat). > > > > It sounds like it needs a pair of system GTTs to hold the table and > column statistics for other GTTs. One would probably have the same > columns as pg_statistic, and the other just the relevant columns from > pg_class. I can see it being useful for the user to be able to see > these stats, so perhaps they could be UNIONed into the existing stats > view. > +1 Pavel > Regards, > Dean >
