From: Laurenz Albe <laurenz.albe@cybertec.at>
To: Mariel Cherkassky <mariel.cherkassky@gmail.com>
To: PostgreSQL mailing lists <pgsql-performance@postgresql.org>
Subject: Re: pgstattuple_approx for toasted table
Date: Mon, 04 Mar 2019 06:21:39 +0100
Message-ID: <43864a0e35504ffc6047dd90eaf648287ed75e65.camel@cybertec.at> (raw)
In-Reply-To: <CA+t6e1kTYbcQY4ohOS-OUvyu5T+=PTj_TZKvyMBeCS5V6V7ZFA@mail.gmail.com>
References: <CA+t6e1kTYbcQY4ohOS-OUvyu5T+=PTj_TZKvyMBeCS5V6V7ZFA@mail.gmail.com>
Mariel Cherkassky wrote:
> I was testing pgstattuple and I realized that pgstattuple is working on toasted table but pgstattuple_approx is raising the next error msg :
>
> ERROR: "pg_toast_18292" is not a table or materialized view
>
> ahm, is that because the pgstattuple_approx uses visibility map ? Can someone explain ? tnx.
You are right; here is the code:
/*
* We support only ordinary relations and materialised views, because we
* depend on the visibility map and free space map for our estimates about
* unscanned pages.
*/
if (!(rel->rd_rel->relkind == RELKIND_RELATION ||
rel->rd_rel->relkind == RELKIND_MATVIEW))
ereport(ERROR,
(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
errmsg("\"%s\" is not a table or materialized view",
RelationGetRelationName(rel))));
Yours,
Laurenz Albe
--
Cybertec | https://www.cybertec-postgresql.com
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To: pgsql-performance@postgresql.org
Cc: laurenz.albe@cybertec.at, mariel.cherkassky@gmail.com
Subject: Re: pgstattuple_approx for toasted table
In-Reply-To: <43864a0e35504ffc6047dd90eaf648287ed75e65.camel@cybertec.at>
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