Horton

Re: Make COPY format extendable: Extract COPY TO format implementations

Li, Yong <yoli@ebay.com>

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From: "Li, Yong" <yoli@ebay.com>
To: Sutou Kouhei <kou@clear-code.com>
Cc: Andres Freund <andres@anarazel.de>, Michael Paquier <michael@paquier.xyz>, "sawada.mshk@gmail.com" <sawada.mshk@gmail.com>, "zhjwpku@gmail.com" <zhjwpku@gmail.com>, "andrew@dunslane.net" <andrew@dunslane.net>, Nathan Bossart <nathandbossart@gmail.com>, "pgsql-hackers@postgresql.org" <pgsql-hackers@postgresql.org>, Tomas Vondra <tomas.vondra@enterprisedb.com>
Date: 2024-07-22T07:11:15Z
Lists: pgsql-hackers 
Hi Kou,

I tried to follow the thread but had to skip quite some discussions in the middle part of the thread. From what I read, it appears to me that there were a lot of back-and-forth discussions on the specific implementation details (i.e. do not touch existing format implementation), performance concerns and how to split the patches to make it more manageable.

My understanding is that the provided v17 patch aims to achieve the followings:
- Retain existing format implementations as built-in formats, and do not go through the new interface for them.
- Make sure that there is no sign of performance degradation.
- Refactoring the existing code to make it easier and possible to make copy handlers extensible. However, some of the infrastructure work that are required to make copy handler extensible are intentionally delayed for future patches. Some of the work were proposed as patches in earlier messages, but they were not explicitly referenced in recent messages.

Overall, the current v17 patch applies cleanly to HEAD. “make check-world” also runs cleanly. If my understanding of the current status of the patch is correct, the patch looks good to me.


Regards,
Yong

Commits

  1. Refactor Copy{From|To}GetRoutine() to use pass-by-reference argument.

  2. Refactor COPY FROM to use format callback functions.

  3. Refactor COPY TO to use format callback functions.

  4. Another try to fix BF failure introduced in commit ddd5f4f54a.

  5. Revert "Refactor CopyReadAttributes{CSV,Text}() to use a callback in COPY FROM"

  6. Improve COPY TO performance when server and client encodings match

  7. Simplify signature of CopyAttributeOutCSV() in copyto.c

  8. Revert "Refactor CopyAttributeOut{CSV,Text}() to use a callback in COPY TO"

  9. Refactor CopyAttributeOut{CSV,Text}() to use a callback in COPY TO

  10. Refactor CopyReadAttributes{CSV,Text}() to use a callback in COPY FROM

  11. Add progress reporting of skipped tuples during COPY FROM.

  12. pgbench: Add \syncpipeline

  13. meson: Make gzip and tar optional

  14. Export the external file reader used in COPY FROM as APIs.