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From: Chao Li <[email protected]>
To: Fujii Masao <[email protected]>
Cc: Jim Jones <[email protected]>
Cc: PostgreSQL Hackers <[email protected]>
Subject: Re: Show comments in \dRp+, \dRs+, and \dX+ psql meta-commands
Date: Thu, 26 Feb 2026 13:07:06 +0800
Message-ID: <[email protected]> (raw)
In-Reply-To: <CAHGQGwFJKg-aT5vajSU1v_B4K129u_SjZ3EGGHFSBhW967gcMA@mail.gmail.com>
References: <CAHGQGwGL4JqiKA26fnGx-cTM=VzoTs_uzqejvj4Fawyr4uLUUw@mail.gmail.com>
	<[email protected]>
	<CAHGQGwFJKg-aT5vajSU1v_B4K129u_SjZ3EGGHFSBhW967gcMA@mail.gmail.com>



> On Feb 26, 2026, at 11:32, Fujii Masao <[email protected]> wrote:
> 
> 
>> One unrelated thing caught my attention though: NULLs and empty strings
>> are both displayed as NULL, which is expected according to
>> CreateComments() in comment.c
>> 
>> ...
>> /* Reduce empty-string to NULL case */
>> if (comment != NULL && strlen(comment) == 0)
>>  comment = NULL;
>> ...
>> 
>> However, I couldn't find anything in the docs that clearly says that
>> it's going to be the case -- at least not in comment.sgml.
>> 
>> CREATE SEQUENCE s1;
>> COMMENT ON SEQUENCE s1 IS '';
>> CREATE SEQUENCE s2;
>> COMMENT ON SEQUENCE s2 IS NULL;
>> 
>> postgres=# \ds+
>> List of sequences
>> -[ RECORD 1 ]-----------
>> Schema      | public
>> Name        | s1
>> Type        | sequence
>> Owner       | jim
>> Persistence | permanent
>> Size        | 8192 bytes
>> Description | (null)
>> -[ RECORD 2 ]-----------
>> Schema      | public
>> Name        | s2
>> Type        | sequence
>> Owner       | jim
>> Persistence | permanent
>> Size        | 8192 bytes
>> Description | (null)
>> 
>> Is it perhaps an undocumented behaviour?
> 
> I'm not sure why this behavior isn't documented, but it seems worth
> addressing in a separate documentation patch.
> 

Actually, I am right about to post a doc patch for that. I noticed that while reviewing the other patch about comment before the holiday vacation. My patch will be out today or tomorrow.

Best regards,
--
Chao Li (Evan)
HighGo Software Co., Ltd.
https://www.highgo.com/

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