Horton

Re: Corruption during WAL replay

Robert Haas <robertmhaas@gmail.com>

View thread View on postgr.es
From: Robert Haas <robertmhaas@gmail.com>
To: Tom Lane <tgl@sss.pgh.pa.us>
Cc: Andres Freund <andres@anarazel.de>, Daniel Gustafsson <daniel@yesql.se>, Kyotaro Horiguchi <horikyota.ntt@gmail.com>, deniel1495@mail.ru, Ibrar Ahmed <ibrar.ahmad@gmail.com>, tejeswarm@hotmail.com, hlinnaka <hlinnaka@iki.fi>, Masahiko Sawada <masahiko.sawada@2ndquadrant.com>, "pgsql-hackers@postgresql.org" <pgsql-hackers@postgresql.org>, Daniel Wood <hexexpert@comcast.net>
Date: 2022-03-25T14:49:22Z
Lists: pgsql-hackers 
On Fri, Mar 25, 2022 at 10:34 AM Tom Lane <tgl@sss.pgh.pa.us> wrote:
> I dunno.  Compatibility and speed concerns aside, that seems like an awful
> lot of bits to be expending on every page compared to the value.

I dunno either, but over on the TDE thread people seemed quite willing
to expend like 16-32 *bytes* for page verifiers and nonces and things.
For compatibility and speed reasons, I doubt we could ever get by with
doing that in every cluster, but I do have some hope of introducing
something like that someday at least as an optional feature. It's not
like a 16-bit checksum was state-of-the-art even when we introduced
it. We just did it because we had 2 bytes that we could repurpose
relatively painlessly, and not any larger number. And that's still the
case today, so at least in the short term we will have to choose some
other solution to this problem.

--
Robert Haas
EDB: http://www.enterprisedb.com

Commits

  1. Harden TAP tests that intentionally corrupt page checksums.

  2. Fix possible recovery trouble if TRUNCATE overlaps a checkpoint.

  3. Remember to reset yy_start state when firing up repl_scanner.l.