Message-ID: <77bbd451633a2852181fc6259baf9796361ce2a1.camel@cybertec.at>
Subject: Re: Indexes on Expressions - a note to remind users to run ANALYZE
 after creation
From: Laurenz Albe <laurenz.albe@cybertec.at>
To: Nikolay Samokhvalov <samokhvalov@gmail.com>, PostgreSQL-documentation
	 <pgsql-docs@postgresql.org>
Date: Mon, 19 Jul 2021 12:59:10 +0200
In-Reply-To: 
 <CANNMO+K179bhRrzsJZn-tS8evH4uRSonCUHoMQdRCSvzmKyo1Q@mail.gmail.com>
References: 
	<CANNMO+K179bhRrzsJZn-tS8evH4uRSonCUHoMQdRCSvzmKyo1Q@mail.gmail.com>
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On Fri, 2021-07-16 at 22:00 -0700, Nikolay Samokhvalov wrote:
> diff --git a/doc/src/sgml/indices.sgml b/doc/src/sgml/indices.sgml
> index 671299ff059d972ff95bdb1d67ed4c89bf5040b2..c7eaf9a608e995ef9957b4e0f677b36a8303be55 100644
> --- a/doc/src/sgml/indices.sgml
> +++ b/doc/src/sgml/indices.sgml
> @@ -741,6 +741,15 @@ CREATE INDEX people_names ON people ((first_name || ' ' || last_name));
>     query.  Thus, indexes on expressions are useful when retrieval speed
>     is more important than insertion and update speed.
>    </para>
> +
> +  <note>
> +   <title>Note</title>
> +   <para>
> +    Once an index on an expression is successfully created, it is important to
> +    run <literal>ANALYZE</literal> on the corresponding table to gather
> +    statistics for the expression.
> +   </para>
> +  </note>
>   </sect1>

I agree in principle.  It should be "has been created" rather than "is created",
and I would say something less drastic like "usually a good idea" rather than
"important".

Yours,
Laurenz Albe