Horton

Re: [COMMITTERS] pgsql: Fix freezing of a dead HOT-updated tuple

Peter Geoghegan <pg@bowt.ie>

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From: Peter Geoghegan <pg@bowt.ie>
To: Alvaro Herrera <alvherre@alvh.no-ip.org>
Cc: "Wood, Dan" <hexpert@amazon.com>, Michael Paquier <michael.paquier@gmail.com>, "Wong, Yi Wen" <yiwong@amazon.com>, PostgreSQL Hackers <pgsql-hackers@postgresql.org>
Date: 2017-10-06T17:03:51Z
Lists: pgsql-hackers 
On Fri, Oct 6, 2017 at 6:18 AM, Alvaro Herrera <alvherre@alvh.no-ip.org> wrote:
> Wood, Dan wrote:
>> Yes, I’ve been testing 9.6.  I’ll try Alvaro’s patch today.
>>
>> I would prefer to focus on either latest 9X or 11dev.
>
> I tested my patch on 9.4 and 9.5 today and it seems to close the problem
> (with the patch, I waited 10x as many iterations as it took for the
> problem to occur ~10 times without the patch), but I can reproduce a
> problem in 9.6 with my patch installed.  There must be something new in
> 9.6 that is causing the problem to reappear.

What problem persists? The original one (or, at least, the original
symptom of pruning HOT chains incorrectly)? If that's what you mean, I
wouldn't be so quick to assume that it's the freeze map.

-- 
Peter Geoghegan

Commits

  1. Backport addition of rs_old_rel to rewriteheap's state.

  2. Perform a lot more sanity checks when freezing tuples.

  3. Revert bogus fixes of HOT-freezing bug

  4. Fix traversal of half-frozen update chains

  5. Fix freezing of a dead HOT-updated tuple

  6. During index build, check and elog (not just Assert) for broken HOT chain.

  7. Fix WAL replay of locking an updated tuple

  8. Change the way we mark tuples as frozen.