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help / color / mirror / Atom feedFrom: Holger Jakobs <[email protected]>
To: [email protected]
Subject: Re: Duplicate Extended Statistics
Date: Wed, 4 Sep 2024 10:43:12 +0200
Message-ID: <[email protected]> (raw)
In-Reply-To: <CAJ9xe=u0FykfAi-ihsjVRkZ3XiJLbW97+BYhEnFo1_3wcps8AA@mail.gmail.com>
References: <[email protected]>
<CAJ9xe=u0FykfAi-ihsjVRkZ3XiJLbW97+BYhEnFo1_3wcps8AA@mail.gmail.com>
Am 04.09.24 um 10:28 schrieb Asad Ali:
> Hi Ilia,
>
> In PostgreSQL, it is possible to create duplicate extended statistics
> because the system does not enforce uniqueness on statistics
> definitions. However, this is generally not recommended, as it leads
> to longer ANALYZE times, increased storage usage, potential planner
> performance impact, and unnecessary complexity. In practice,
> duplicates are rare because users and tools usually avoid redundancy,
> as there is no added benefit to having multiple identical sets of
> statistics on the same columns.
>
> Regards,
> Asad Ali
>
>
To find duplicate indexes:
SELECT indrelid::regclass::text AS "Table Name",
string_agg(indexrelid::regclass::text ||
CASE WHEN indisunique
THEN ' (UNIQUE)' ELSE ''
END, ', ') AS "Indexes"
FROM pg_index
GROUP BY indrelid, indkey
HAVING COUNT(*) > 1
--
Holger Jakobs, Bergisch Gladbach
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