From: William Sescu (Suva) <william.sescu@suva.ch>
To: Tom Lane <tgl@sss.pgh.pa.us>
Cc: pgsql-admin@postgresql.org <pgsql-admin@postgresql.org>
Subject: AW: No result when selecting attstattarget from pg_attribute
Date: Thu, 28 Nov 2019 15:14:13 +0000
Message-ID: <9545ee300c12457f8ef09c8708d45f31@suva.ch> (raw)
In-Reply-To: <31263.1574952854@sss.pgh.pa.us>
References: <4078c426dbbb4e18a047ec00485adba9@suva.ch>
<31263.1574952854@sss.pgh.pa.us>
Thank you Tom for clarification. However, in regards of pg_upgrade, which does not transfer statistics, how do I know
how to create the "CREATE STATISTICS" on the new PostgreSQL version?
e.g. Developers created a whole bunch of "CREATE STATISTICS" on all kind of tables, which ends up in pg_statistic_ext view.
select * from pg_statistic_ext;
stxrelid | stxname | stxnamespace | stxowner | stxkeys | stxkind | stxndistinct | stxdependencies
----------+---------+--------------+----------+---------+---------+--------------+----------------------
35600 | s1 | 16579 | 16569 | 1 2 | {f} | | {"1 => 2": 1.000000}
Is there any way how I can translate the view entries into into a SQL again?
CREATE STATISTICS s1 (dependencies) ON a, b FROM t1;
-----Ursprüngliche Nachricht-----
Von: Tom Lane <tgl@sss.pgh.pa.us>
Gesendet: Donnerstag, 28. November 2019 15:54
An: Sescu William (SW0) <william.sescu@suva.ch>
Cc: pgsql-admin@postgresql.org
Betreff: Re: No result when selecting attstattarget from pg_attribute
"William Sescu (Suva)" <william.sescu@suva.ch> writes:
> I was following the create statistics example from the doc
> https://www.postgresql.org/docs/11/sql-createstatistics.html
> and wondered why I don't see any results when selecting attstattarget from pg_attribute.
attstattarget has nothing to do with extended statistics.
It's for recording "ALTER TABLE ... SET STATISTICS n"
commands, which just control the granularity of the regular (pg_statistic) statistics.
Look into pg_statistic_ext to see the effects of CREATE STATISTICS.
regards, tom lane
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To: pgsql-admin@postgresql.org
Cc: william.sescu@suva.ch, tgl@sss.pgh.pa.us
Subject: Re: AW: No result when selecting attstattarget from pg_attribute
In-Reply-To: <9545ee300c12457f8ef09c8708d45f31@suva.ch>
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