Feedback-ID: ie0a040ee:Fastmail
Message-ID: <0f6a8a8a-b42e-433b-89cd-ee121d0919b3@eisentraut.org>
Date: Fri, 7 Mar 2025 12:05:53 +0100
MIME-Version: 1.0
User-Agent: Mozilla Thunderbird
Subject: Re: pgsql: Generalize hash and ordering support in amapi
To: Tom Lane <tgl@sss.pgh.pa.us>
Cc: Mark Dilger <mark.dilger@enterprisedb.com>,
 pgsql-committers@lists.postgresql.org
References: <E1tngY6-0000UL-2n@gemulon.postgresql.org>
 <2557074.1740673653@sss.pgh.pa.us>
 <CAHgHdKuCQ3Dh8wt9QxWRmezgE62qzYW86T9Mv1n5s3fOJ4G2dQ@mail.gmail.com>
 <1789fe14-c19d-4025-9201-0eb8faa0840b@eisentraut.org>
 <165328.1741109742@sss.pgh.pa.us>
Content-Language: en-US
From: Peter Eisentraut <peter@eisentraut.org>
In-Reply-To: <165328.1741109742@sss.pgh.pa.us>
Content-Type: text/plain; charset=UTF-8; format=flowed
Content-Transfer-Encoding: 7bit
Archived-At: 
 <https://www.postgresql.org/message-id/0f6a8a8a-b42e-433b-89cd-ee121d0919b3%40eisentraut.org>
Precedence: bulk

On 04.03.25 18:35, Tom Lane wrote:
> In any case, my gripe was less about the name of the flag and more
> about the lack of a clear specification of what it means.  "does AM
> support cross-type comparisons" doesn't get the job done.  Maybe
> we can fit
> 
>      /* do operators within an opfamily have consistent equality semantics? */
>      bool        amconsistentequality;
>      /* do operators within an opfamily have consistent ordering semantics? */
>      bool        amconsistentordering;

> Also, I'm thinking that equality_ops_are_compatible and
> comparison_ops_are_compatible now have a bit of a performance problem.
> The original coding was intended to provide a cheap check before
> expending the cycles to test op_in_opfamily.  This patch has
> completely blown that up, since GetIndexAmRoutineByAmId is *more*
> expensive than op_in_opfamily.  I suggest reversing things so that we
> test op_in_opfamily first and only bother to look up the AM details
> when we've verified that both operators belong to the same family.

I have committed fixes for these issues along the lines you suggested.