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Date: Wed, 18 Sep 2024 10:09:38 +0200
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Subject: Re: information_schema.view attgenerated
To: jian he <jian.universality@gmail.com>,
 PostgreSQL Hackers <pgsql-hackers@lists.postgresql.org>
References: <CACJufxHO3=BA=9S1RAG3=Rp_E=C_ShO9UFfTniEHdMTp4mTS9A@mail.gmail.com>
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From: Peter Eisentraut <peter@eisentraut.org>
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On 16.09.24 06:12, jian he wrote:
> hi.
> one minor issue in src/backend/catalog/information_schema.sql
> /*
>   * 6.22
>   * COLUMNS view
>   */
> CREATE VIEW columns ....
> 
> 
> CAST(CASE WHEN a.attgenerated = '' THEN pg_get_expr(ad.adbin,
> ad.adrelid) END AS character_data) AS column_default,
> can change to
> CAST(CASE WHEN a.attgenerated = '' AND a.atthasdef THEN
> pg_get_expr(ad.adbin, ad.adrelid) END AS character_data) AS
> column_default,
> 
> 
> CAST(CASE WHEN a.attgenerated <> '' THEN 'ALWAYS' ELSE 'NEVER' END AS
> character_data) AS is_generated,
> can change to
> CAST(CASE WHEN a.attgenerated <> '' AND a.atthasdef THEN 'ALWAYS' ELSE
> 'NEVER' END AS character_data) AS is_generated,
> 
> CAST(CASE WHEN a.attgenerated <> '' THEN pg_get_expr(ad.adbin,
> ad.adrelid) END AS character_data) AS generation_expression,
> can change to
> CAST(CASE WHEN a.attgenerated <> '' AND a.atthasdef THEN
> pg_get_expr(ad.adbin, ad.adrelid) END AS character_data) AS
> generation_expression,
> 
> 
> i guess, it will have some minor speed up, also more accurate.

I'm having a hard time interpreting this report.  Could you be more 
clear about what is the existing code, and what is the code you are 
proposing as new.?