Re: Indexes on Expressions - a note to remind users to run ANALYZE after creation

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