Re: [HACKERS] [PATCH] A hook for session start - Mailing list pgsql-hackers

From Nico Williams
Subject Re: [HACKERS] [PATCH] A hook for session start
Date
Msg-id 20171007044927.GA3093@localhost
Whole thread Raw
In response to Re: [HACKERS] [PATCH] A hook for session start  (Pavel Stehule <pavel.stehule@gmail.com>)
Responses Re: [HACKERS] [PATCH] A hook for session start  (Pavel Stehule <pavel.stehule@gmail.com>)
List 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@cryptonector.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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