Horton

Re: FSM Corruption (was: Could not read block at end of the relation)

Peter Geoghegan <pg@bowt.ie>

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From: Peter Geoghegan <pg@bowt.ie>
To: Noah Misch <noah@leadboat.com>
Cc: Ronan Dunklau <ronan.dunklau@aiven.io>, Michael Paquier <michael@paquier.xyz>, pgsql-bugs <pgsql-bugs@lists.postgresql.org>
Date: 2024-04-11T16:01:09Z
Lists: pgsql-bugs 
On Wed, Mar 13, 2024 at 12:55 PM Noah Misch <noah@leadboat.com> wrote:
> That's a reasonable thing to worry about.  We could do wrong by trying too
> hard to use an FSM slot, and we could do wrong by not trying hard enough.

Although it's not related to the problem you're working on, it seems
like a good opportunity to bring up a concern about the FSM that I
don't believe was discussed at any point in the past few years: I
wonder if the way that fsm_search_avail() sometimes updates
fsmpage->fp_next_slot with only a shared lock on the page could cause
problems. At the very least, it's weird that we allow it.

-- 
Peter Geoghegan

Commits

  1. freespace: Don't return blocks past the end of the main fork.

  2. Fix WAL-logging of FSM and VM truncation.

  3. Extend relations multiple blocks at a time to improve scalability.