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

On Wed, Aug 15, 2018 at 11:08 AM, Asim R P <apraveen(at)pivotal(dot)io> wrote:
> I was looking at the commitfest entry for feature
> (https://commitfest.postgresql.org/19/1639/) for the most recent list
> of patches to try out. The list doesn't look correct/complete. Can
> someone please check?

Hi Asim,

This thread is a bit tangled up. There are two related patchsets in it:

1. Craig Ringer's PANIC-on-EIO patch set, to cope with the fact that
Linux throws away buffers and errors after reporting an error, so the
checkpointer shouldn't retry as it does today. The latest is here:

https://www.postgresql.org/message-id/CAMsr%2BYFPeKVaQ57PwHqmRNjPCPABsdbV%3DL85he2dVBcr6yS1mA%40mail.gmail.com

2. Andres Freund's fd-sending fsync queue, to cope with the fact that
some versions of Linux only report writeback errors that occurred
after you opened the file, and all versions of Linux and some other
operating systems might forget about writeback errors while no one has
it open.

Here is the original patchset:

https://www.postgresql.org/message-id/20180522010823.z5bdq7wnlsna5qoo%40alap3.anarazel.de

Here is a fix-up you need:

https://www.postgresql.org/message-id/20180522185951.5sdudzl46spktyyz%40alap3.anarazel.de

Here are some more fix-up patches that I propose:

https://www.postgresql.org/message-id/CAEepm%3D2WSPP03-20XHpxohSd2UyG_dvw5zWS1v7Eas8Rd%3D5e4A%40mail.gmail.com

I will soon post some more fix-up patches that add EXEC_BACKEND
support, Windows support, and a counting scheme to fix the timing
issue that I mentioned in my first review. I will probably squash it
all down to a tidy patch-set after that.

--
Thomas Munro
http://www.enterprisedb.com