Horton

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

Sutou Kouhei <kou@clear-code.com>

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From: Sutou Kouhei <kou@clear-code.com>
To: michael@paquier.xyz
Cc: andres@anarazel.de, sawada.mshk@gmail.com, zhjwpku@gmail.com, andrew@dunslane.net, nathandbossart@gmail.com, pgsql-hackers@postgresql.org
Date: 2024-03-05T08:18:08Z
Lists: pgsql-hackers

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Hi,

In <Zea4wXxpYaX64e_p@paquier.xyz>
  "Re: Make COPY format extendable: Extract COPY TO format implementations" on Tue, 5 Mar 2024 15:16:33 +0900,
  Michael Paquier <michael@paquier.xyz> wrote:

> CopyOneRowTo() could do something like that to avoid the extra
> indentation:
> if (cstate->routine)
> {
>     cstate->routine->CopyToOneRow(cstate, slot);
>     MemoryContextSwitchTo(oldcontext);
>     return;
> }

OK. The v17 patch uses this style. Others are same as the
v16.

> I didn't know this trick.  That's indeed nice..  I may use that for
> other stuff to make patches more presentable to the eyes.  And that's
> available as well with `git diff`.

:-)

> If we basically agree about this part, how would the rest work out
> with this set of APIs and the possibility to plug in a custom value
> for FORMAT to do a pg_proc lookup, including an example of how these
> APIs can be used?

I'll send the following patches after this patch is
merged. They are based on the v6 patch[1]:

1. Add copy_handler
   * This also adds a pg_proc lookup for custom FORMAT
   * This also adds a test for copy_handler
2. Export CopyToStateData
   * We need it to implement custom copy TO handler
3. Add needed APIs to implement custom copy TO handler
   * Add CopyToStateData::opaque
   * Export CopySendEndOfRow()
4. Export CopyFromStateData
   * We need it to implement custom copy FROM handler
5. Add needed APIs to implement custom copy FROM handler
   * Add CopyFromStateData::opaque
   * Export CopyReadBinaryData()

[1] https://www.postgresql.org/message-id/flat/20240124.144936.67229716500876806.kou%40clear-code.com#f1ad092fc5e81fe38d3c376559efd52c


Thanks,
-- 
kou

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.