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: 2024-03-01T06:44:43Z
Lists: pgsql-hackers 
Hi,

In <ZeFoOprWyKU6gpkP@paquier.xyz>
  "Re: Make COPY format extendable: Extract COPY TO format implementations" on Fri, 1 Mar 2024 14:31:38 +0900,
  Michael Paquier <michael@paquier.xyz> wrote:

> I guess so.  It does not make much of a difference, though.  The thing
> is that the dispatch caused by the custom callbacks called for each
> row is noticeable in any profiles I'm taking (not that much in the
> worst-case scenarios, still a few percents), meaning that this impacts
> the performance for all the in-core formats (text, csv, binary) as
> long as we refactor text/csv/binary to use the routines of copyapi.h.
> I don't really see a way forward, except if we don't dispatch the
> in-core formats to not impact the default cases.  That makes the code
> a bit less elegant, but equally efficient for the existing formats.

It's an option based on your profile result but your
execution result also shows that v15 is faster than HEAD [1]:

> I am getting faster runtimes with v15 (6232ms in average)
> vs HEAD (6550ms) at 5M rows with COPY TO

[1] https://www.postgresql.org/message-id/flat/ZdbtQJ-p5H1_EDwE%40paquier.xyz#6439e6ad574f2d47cd7220e9bfed3889

I think that faster runtime is beneficial than mysterious
profile for users. So I think that we can merge v15 to
master.


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.