Horton

Re: new heapcheck contrib module

Robert Haas <robertmhaas@gmail.com>

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From: Robert Haas <robertmhaas@gmail.com>
To: Mark Dilger <mark.dilger@enterprisedb.com>
Cc: Andres Freund <andres@anarazel.de>, PostgreSQL-development <pgsql-hackers@postgresql.org>, Peter Geoghegan <pg@bowt.ie>
Date: 2020-04-29T18:56:37Z
Lists: pgsql-hackers 
On Wed, Apr 29, 2020 at 12:30 PM Mark Dilger
<mark.dilger@enterprisedb.com> wrote:
> Version 4 of this patch now includes boolean options skip_all_frozen and skip_all_visible.

I'm not sure sure, but maybe there should just be one argument with
three possible values, because skip_all_frozen = true and
skip_all_visible = false seems nonsensical. On the other hand, if we
used a text argument with three possible values, I'm not sure what
we'd call the argument or what strings we'd use as the values.

Also, what do people -- either those who have already responded, or
others -- think about the idea of putting a command-line tool around
this? I know that there were some rumblings about this in respect to
pg_verifybackup, but I think a pg_amcheck binary would be
well-received. It could do some interesting things, too. For instance,
it could query pg_class for a list of relations that amcheck would
know how to check, and then issue a separate query for each relation,
which would avoid holding a snapshot or heavyweight locks across the
whole operation. It could do parallelism across relations by opening
multiple connections, or even within a single relation if -- as I
think would be a good idea -- we extended heapcheck to take a range of
block numbers after the style of pg_prewarm.

Apart from allowing for client-driven parallelism, accepting block
number ranges would have the advantage -- IMHO pretty significant --
of making it far easier to use this on a relation where some blocks
are entirely unreadable. You could specify ranges to check out the
remaining blocks.

-- 
Robert Haas
EnterpriseDB: http://www.enterprisedb.com
The Enterprise PostgreSQL Company

Commits

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

  2. Refactor and generalize the ParallelSlot machinery.

  3. Generalize parallel slot result handling.

  4. Move some code from src/bin/scripts to src/fe_utils to permit reuse.

  5. Factor pattern-construction logic out of processSQLNamePattern.

  6. Doc: clean up verify_heapam() documentation.

  7. Fix more portability issues in new amcheck code.

  8. Fix portability issues in new amcheck test.

  9. Try to avoid a compiler warning about using fxid uninitialized.

  10. Extend amcheck to check heap pages.

  11. Adjust walsender usage of xlogreader, simplify APIs

  12. Improve checking of child pages in contrib/amcheck.

  13. Sanitize line pointers within contrib/amcheck.

  14. Fix possible sorting error when aborting use of abbreviated keys.