Subject: Re: [HACKERS] [WIP] Effective storage of duplicates in B-tree index.
To: Peter Geoghegan <pg@bowt.ie>
Cc: Heikki Linnakangas <hlinnaka@iki.fi>,
 PostgreSQL Hackers <pgsql-hackers@lists.postgresql.org>,
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From: Anastasia Lubennikova <a.lubennikova@postgrespro.ru>
Message-ID: <ed918743-bf32-b8af-0620-e07c1d81ce2f@postgrespro.ru>
Date: Thu, 20 Feb 2020 18:38:22 +0300
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On 19.02.2020 22:16, Peter Geoghegan wrote:
> On Wed, Feb 19, 2020 at 8:14 AM Anastasia Lubennikova
> <a.lubennikova@postgrespro.ru> wrote:
>> Thank you for this work. I've looked through the patches and they seem
>> to be ready for commit.
>> I haven't yet read recent documentation and readme changes, so maybe
>> I'll send some more feedback tomorrow.

The only thing I found is a typo in the comment

+  int      nhtids;      /* Number of heap TIDs in nhtids array */

s/nhtids/htids

I don't think this patch really needs more nitpicking )

>
>> In my opinion, this message is too specific for default behavior. It
>> exposes internal details without explanation and may look to user like
>> something went wrong.
> You're probably right about that. I just wish that there was some way
> of showing the same information that was discoverable, and didn't
> require the use of pageinspect. If I make it a DEBUG1 message, then it
> cannot really be documented.

User can discover this with a complex query to pg_index and pg_opclass.
To simplify this, we can probably wrap this into function or some field 
in pg_indexes.
Anyway, I would wait for feedback from pre-release testers.