Horton

Re: Online checksums verification in the backend

Michael Paquier <michael@paquier.xyz>

View thread View on postgr.es
From: Michael Paquier <michael@paquier.xyz>
To: Julien Rouhaud <rjuju123@gmail.com>
Cc: Justin Pryzby <pryzby@telsasoft.com>, Masahiko Sawada <masahiko.sawada@2ndquadrant.com>, Robert Haas <robertmhaas@gmail.com>, PostgreSQL Hackers <pgsql-hackers@lists.postgresql.org>, Masahiko Sawada <sawada.mshk@gmail.com>
Date: 2020-10-28T05:08:52Z
Lists: pgsql-hackers 
On Tue, Oct 27, 2020 at 07:47:19PM +0800, Julien Rouhaud wrote:
> I think it's also worth noting that the IOLock is now acquired just
> before getting the buffer state, and released after the read (or after
> finding that the buffer is dirty).  This is consistent with how it's
> done elsewhere, so I'm fine.

Consistency is the point.  This API should be safe to use by design.
I have done some extra performance tests similar to what I did
upthread, and this version showed similar numbers.

> Other than that I'm quite happy with the changes you made, thanks a lot!

Thanks for confirming.  I have gone through the whole set today,
splitted the thing into two commits and applied them.  We had
buildfarm member florican complain about a mistake in one of the
GetDatum() calls that I took care of already, and there is nothing
else on my radar.
--
Michael

Commits

  1. Revert pg_relation_check_pages()

  2. Fix incorrect placement of pfree() in pg_relation_check_pages()

  3. Add pg_relation_check_pages() to check on-disk pages of a relation

  4. Add CheckBuffer() to check on-disk pages without shared buffer loading

  5. Extend amcheck to check heap pages.