Horton

Re: [BUG] Error in BRIN summarization

Peter Geoghegan <pg@bowt.ie>

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From: Peter Geoghegan <pg@bowt.ie>
To: Alvaro Herrera <alvherre@2ndquadrant.com>
Cc: Anastasia Lubennikova <a.lubennikova@postgrespro.ru>, PostgreSQL Hackers <pgsql-hackers@lists.postgresql.org>
Date: 2020-07-28T19:18:09Z
Lists: pgsql-hackers 
On Mon, Jul 27, 2020 at 10:25 AM Alvaro Herrera
<alvherre@2ndquadrant.com> wrote:
> (I was also considering whether it needs to be a loop to reobtain root
> tuples, in case a concurrent transaction can create a new item while
> we're checking that item; but I don't think that can really happen for
> one individual tuple.)

I wonder if something like that is the underlying problem in a recent
problem case involving a "REINDEX index
pg_class_tblspc_relfilenode_index" command that runs concurrently with
the regression tests:

https://postgr.es/m/CAH2-WzmBxu4o=pMsniur+bwHqCGCmV_AOLkuK6BuU7ngA6evqw@mail.gmail.com

We see a violation of the HOT invariant in this case, though only for
a system catalog index, and only in fairly particular circumstances
involving concurrency.

-- 
Peter Geoghegan

Commits

  1. Disable autovacuum for BRIN test table

  2. Handle new HOT chains in index-build table scans

  3. BRIN: Handle concurrent desummarization properly