From: Christoph Berg <myon@debian.org>
To: Tom Lane <tgl@sss.pgh.pa.us>
Cc: Pavel Stehule <pavel.stehule@gmail.com>
Cc: Tomas Vondra <tomas.vondra@2ndquadrant.com>
Cc: PostgreSQL Hackers <pgsql-hackers@postgresql.org>
Cc: Aleksander Alekseev <a.alekseev@postgrespro.ru>
Subject: Re: [Patch] Temporary tables that do not bloat pg_catalog (a.k.a fast temp tables)
Date: Mon, 15 Aug 2016 13:10:57 +0200
Message-ID: <20160815111057.v2mqqjp4aabvwqnc@msg.df7cb.de> (raw)
In-Reply-To: <1184.1469890030@sss.pgh.pa.us>
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Re: Tom Lane 2016-07-30 <1184.1469890030@sss.pgh.pa.us>
> In short, I think that the way to make something like this work is to
> figure out how to have "virtual" catalog rows describing a temp table.
> Or maybe to partition the catalogs so that vacuuming away temp-table
> rows is easier/cheaper than today.
We should also be thinking about how the opposite idea of "global"
temp tables (I believe that's what Oracle calls them) would work.
These have a persistent structure in the catalogs, just the data is
private to every session (or transaction); every connection starts
with an empty temp table and for their use.
I'd guess that type of global temp tables would fix the bloat problem
also very efficiently. (Ad-hoc temp tables shouldn't occur that often
so the bloat caused by them wouldn't matter that much. If they do,
their structure is likely always the same, and they could be made
"global" in the schema.)
The bit that needs to be thought out here would be how to maintain
statistics for these tables. Obviously ANALYZE shouldn't update any
globally visible data.
Christoph
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Cc: myon@debian.org, tgl@sss.pgh.pa.us, pavel.stehule@gmail.com, tomas.vondra@2ndquadrant.com, a.alekseev@postgrespro.ru
Subject: Re: [Patch] Temporary tables that do not bloat pg_catalog (a.k.a fast temp tables)
In-Reply-To: <20160815111057.v2mqqjp4aabvwqnc@msg.df7cb.de>
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