| From: | Nico Williams <nico(at)cryptonector(dot)com> |
|---|---|
| To: | Pavel Stehule <pavel(dot)stehule(at)gmail(dot)com> |
| Cc: | Peter Eisentraut <peter(dot)eisentraut(at)2ndquadrant(dot)com>, Jim Mlodgenski <jimmy76(at)gmail(dot)com>, Robert Haas <robertmhaas(at)gmail(dot)com>, Craig Ringer <craig(at)2ndquadrant(dot)com>, Yugo Nagata <nagata(at)sraoss(dot)co(dot)jp>, PostgreSQL Hackers <pgsql-hackers(at)postgresql(dot)org>, Fabrízio de Royes Mello <fabriziomello(at)gmail(dot)com> |
| Subject: | Re: [PATCH] A hook for session start |
| Date: | 2017-10-07 04:49:28 |
| Message-ID: | 20171007044927.GA3093@localhost |
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| Lists: | pgsql-hackers |
On Sat, Oct 07, 2017 at 05:44:00AM +0200, Pavel Stehule wrote:
> 2017-10-06 21:36 GMT+02:00 Nico Williams <nico(at)cryptonector(dot)com>:
> > But the nice thing about them is that you need only create them once, so
> > leave them in the catalog. Stats about them should not be gathered nor
> > stored, since they could be different per-session.
>
> Unfortunately one field from pg_class are not static - reltuples should be
> per session.
It's "only an estimate" "used by the query planner". We could estimate
zero for global temp tables, and the query planner can get the true
value from an internal temp table.
> But it can be moved to different table
That too, if it's OK.
Nico
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