Horton

Re: pg_amcheck contrib application

Robert Haas <robertmhaas@gmail.com>

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From: Robert Haas <robertmhaas@gmail.com>
To: Mark Dilger <mark.dilger@enterprisedb.com>
Cc: Tom Lane <tgl@sss.pgh.pa.us>, Noah Misch <noah@leadboat.com>, Peter Geoghegan <pg@bowt.ie>, Thomas Munro <thomas.munro@gmail.com>, "Andrey M. Borodin" <x4mmm@yandex-team.ru>, Stephen Frost <sfrost@snowman.net>, Michael Paquier <michael@paquier.xyz>, Amul Sul <sulamul@gmail.com>, Dilip Kumar <dilipbalaut@gmail.com>, Andres Freund <andres@anarazel.de>, PostgreSQL-development <pgsql-hackers@postgresql.org>
Date: 2021-03-24T13:12:01Z
Lists: pgsql-hackers 
On Wed, Mar 24, 2021 at 2:13 AM Mark Dilger
<mark.dilger@enterprisedb.com> wrote:
> The visibility rules fix is different in v11, relying on a visibility check which more closely follows the implementation of HeapTupleSatisfiesVacuumHorizon.

Hmm. The header comment you wrote says "If a tuple might not be
visible to any running transaction, then we must not check it." But, I
don't find that statement very clear: does it mean "if there could be
even one transaction to which this tuple is not visible, we must not
check it"? Or does it mean "if the number of transactions that can see
this tuple could potentially be zero, then we must not check it"? I
don't think either of those is actually what we care about. I think
what we should be saying is "if the tuple could have been inserted by
a transaction that also added a column to the table, but which
ultimately did not commit, then the table's current TupleDesc might
differ from the one used to construct this tuple, so we must not check
it."

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

Commits

  1. amcheck: Improve some confusing reports about TOAST problems.

  2. amcheck: Reword some messages and fix an alignment problem.

  3. amcheck: fix multiple problems with TOAST pointer validation

  4. amcheck: Remove duplicate XID/MXID bounds checks.

  5. amcheck: Fix verify_heapam's tuple visibility checking rules.

  6. nbtree VACUUM: Cope with buggy opclasses.

  7. Improve pg_amcheck's TAP test 003_check.pl.

  8. Fix a confusing amcheck corruption message.

  9. Doc: add note about how to run the pg_amcheck regression tests.

  10. In pg_amcheck tests, don't depend on perl's Q/q pack code.

  11. pg_amcheck: Keep trying to fix the tests.

  12. pg_amcheck: Try to fix still more test failures.

  13. Try to avoid apparent platform-dependency in IPC::Run

  14. Fix portability issues in pg_amcheck's 004_verify_heapam.pl.

  15. Try to fix compiler warnings.

  16. Add pg_amcheck, a CLI for contrib/amcheck.

  17. Refactor and generalize the ParallelSlot machinery.

  18. Remove old-style VACUUM FULL (which was known for a little while as