Horton

Re: Postgres, fsync, and OSs (specifically linux)

Andres Freund <andres@anarazel.de>

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From: Andres Freund <andres@anarazel.de>
To: Craig Ringer <craig@2ndquadrant.com>
Cc: Thomas Munro <thomas.munro@enterprisedb.com>, Simon Riggs <simon@2ndquadrant.com>, PostgreSQL Hackers <pgsql-hackers@postgresql.org>
Date: 2018-04-30T02:17:38Z
Lists: pgsql-hackers 
On 2018-04-30 10:14:23 +0800, Craig Ringer wrote:
> Meanwhile, do we know if, on Linux 4.13+, if we get a buffered write
> error due to dirty writeback before we close() a file we don't
> fsync(), we'll get the error on close()?

Not quite sure what you're getting at with "a file we don't fsync" - if
we don't, we don't care about durability anyway, no? Or do you mean
where we fsync in a different process?

Either way, the answer is mostly no: On NFS et al where close() implies
an fsync you'll get the error at that time, otherwise you'll get it at
the next fsync().

Greetings,

Andres Freund

Commits

  1. PANIC on fsync() failure.

  2. Fix and improve pg_atomic_flag fallback implementation.