Horton

Re: should frontend tools use syncfs() ?

Nathan Bossart <nathandbossart@gmail.com>

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From: Nathan Bossart <nathandbossart@gmail.com>
To: Justin Pryzby <pryzby@telsasoft.com>
Cc: Michael Paquier <michael@paquier.xyz>, Thomas Munro <thomas.munro@gmail.com>, David Steele <david@pgmasters.net>, Fujii Masao <masao.fujii@oss.nttdata.com>, Bruce Momjian <bruce@momjian.us>, Paul Guo <guopa@vmware.com>, Tom Lane <tgl@sss.pgh.pa.us>, Michael Brown <michael.brown@discourse.org>, pgsql-hackers@postgresql.org
Date: 2023-07-31T17:51:38Z
Lists: pgsql-hackers

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On Sat, Jul 29, 2023 at 02:40:10PM -0700, Nathan Bossart wrote:
> I was about to start a new thread, but I found this one with some good
> preliminary discussion.  I came to the same conclusion about introducing a
> new option instead of using syncfs() by default wherever it is available.
> The attached patch is still a work-in-progress, but it seems to behave as
> expected.  I began investigating this because I noticed that the
> sync-data-directory step on pg_upgrade takes quite a while when there are
> many files, and I am looking for ways to reduce the amount of downtime
> required for pg_upgrade.
> 
> The attached patch adds a new --sync-method option to the relevant frontend
> utilities, but I am not wedded to that name/approach.

Here is a new version of the patch with documentation updates and a couple
other small improvements.

-- 
Nathan Bossart
Amazon Web Services: https://aws.amazon.com

Commits

  1. Adjust documentation for syncfs().

  2. Improve the naming in wal_sync_method code.

  3. Allow using syncfs() in frontend utilities.

  4. Add support for syncfs() in frontend support functions.

  5. Make enum for sync methods available to frontend code.

  6. Move PG_TEMP_FILE* macros to file_utils.h.

  7. Change client-side fsync_fname() to report errors fatally