Date: Fri, 15 Dec 2023 11:55:18 +0900 (JST)
Message-Id: <20231215.115518.402165846487638860.kou@clear-code.com>
To: kuroda.hayato@fujitsu.com
Cc: zhjwpku@gmail.com, andrew@dunslane.net, michael@paquier.xyz,
 sawada.mshk@gmail.com, nathandbossart@gmail.com,
 pgsql-hackers@postgresql.org
Subject: Re: Make COPY format extendable: Extract COPY TO format
 implementations
From: Sutou Kouhei <kou@clear-code.com>
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Hi,

In 
 <OS3PR01MB9882F023300EDC5AFD8A8339F58EA@OS3PR01MB9882.jpnprd01.prod.outlook.com>
  "RE: Make COPY format extendable: Extract COPY TO format implementations" on Tue, 12 Dec 2023 02:31:53 +0000,
  "Hayato Kuroda (Fujitsu)" <kuroda.hayato@fujitsu.com> wrote:

>> Can we discuss how to proceed this improvement?
>> 
>> There are 2 approaches for it:
>> 
>> 1. Do the followings concurrently:
>>    a. Implementing small changes that got a consensus and
>>       merge them step-by-step
>>       (e.g. We got a consensus that we need to extract the
>>       current format related routines.)
>>    b. Discuss design
>> 
>>    (v1-v3 patches use this approach.)
>> 
>> 2. Implement one (large) complete patch set with design
>>    discussion and merge it
>> 
>>    (v4- patches use this approach.)
>> 
>> Which approach is preferred? (Or should we choose another
>> approach?)
>> 
>> I thought that 1. is preferred because it will reduce review
>> cost. So I chose 1.
> 
> I'm ok to use approach 1, but could you please divide a large patch? E.g.,
> 
> 0001. defines an infrastructure for copy-API
> 0002. adjusts current codes to use APIs
> 0003. adds a test module in src/test/modules or contrib.
> ...
> 
> This approach helps reviewers to see patches deeper. Separated patches can be
> combined when they are close to committable.

It seems that I should have chosen another approach based on
comments so far:

3. Do the followings in order:
   a. Implement a workable (but maybe dirty and/or incomplete)
      implementation to discuss design like [1], discuss
      design with it and get a consensus on design
   b. Implement small patches based on the design

[1]: https://www.postgresql.org/message-id/CAD21AoCunywHird3GaPzWe6s9JG1wzxj3Cr6vGN36DDheGjOjA%40mail.gmail.com 

I'll implement a custom COPY FORMAT handler with [1] and
provide a feedback with the experience. (It's for a.)


Thanks,
-- 
kou