Horton

Re: Add pg_file_sync() to adminpack

Michael Paquier <michael@paquier.xyz>

View thread View on postgr.es
From: Michael Paquier <michael@paquier.xyz>
To: Arthur Zakirov <zaartur@gmail.com>
Cc: Julien Rouhaud <rjuju123@gmail.com>, Fujii Masao <masao.fujii@gmail.com>, PostgreSQL-development <pgsql-hackers@postgresql.org>
Date: 2020-01-06T06:42:39Z
Lists: pgsql-hackers 
On Mon, Jan 06, 2020 at 03:20:13PM +0900, Arthur Zakirov wrote:
> It isn't case if a file doesn't exist. But if there are no permissions on
> the file:
> 
> PANIC:  could not open file "testfile": Permissions denied
> server closed the connection unexpectedly
> 
> It could be fixed by implementing a function like pg_file_sync_internal() or
> by making the function fsync_fname_ext() external.

The patch uses stat() to make sure that the file exists and has no
issues.  Though it could be a problem with any kind of TOCTOU-like
issues (looking at you, Windows, for ENOPERM), so I agree that it
would make more sense to use pg_fsync() here with a fd opened first.
--
Michael

Commits

  1. Add pg_file_sync() to adminpack extension.