Re: [Patch] Temporary tables that do not bloat pg_catalog (a.k.a fast temp tables)

From: Andres Freund <andres(at)anarazel(dot)de>
To: Tomas Vondra <tomas(dot)vondra(at)2ndquadrant(dot)com>
Cc: Vik Fearing <vik(at)2ndquadrant(dot)fr>,Robert Haas <robertmhaas(at)gmail(dot)com>,Jim Nasby <Jim(dot)Nasby(at)bluetreble(dot)com>,Aleksander Alekseev <a(dot)alekseev(at)postgrespro(dot)ru>,PostgreSQL Hackers <pgsql-hackers(at)postgresql(dot)org>
Subject: Re: [Patch] Temporary tables that do not bloat pg_catalog (a.k.a fast temp tables)
Date: 2016-08-31 22:07:56
Message-ID: 7AF1B956-ECEA-474E-AC29-18535F7B5475@anarazel.de
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On August 31, 2016 3:00:15 PM PDT, Tomas Vondra <tomas(dot)vondra(at)2ndquadrant(dot)com> wrote:
>
>
>On 08/31/2016 11:43 PM, Andres Freund wrote:
>> On 2016-08-31 23:40:46 +0200, Tomas Vondra wrote:
>>> It's an improvement (and it's pretty much exactly what I proposed
>>> upthread). But it does not solve the problems with pg_statistic for
>>> example (each backend needs it's own statistics. So we'd either
>bloat
>>> the pg_statistic (if we manage to solve the problem that the table
>has
>>> the same oid in all backends), or we would need in-memory tuples
>(just
>>> like discussed in the thread so far).
>>
>> Creating a session private version of pg_statistic would be fairly
>> simple.
>
>Sure. I'm just saying it's not as simple as overriding relpath.
>
>ISTM we only need the pg_statistics (as other catalogs are connected to
>the pg_class entry), which does not have the dependency issues. Or do
>we
>need other catalogs?

In my experience pg attribute is usually the worst affected. Many tech takes won't even have stays entries...

Andres
--
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