Horton

Re: Show various offset arrays for heap WAL records

Robert Haas <robertmhaas@gmail.com>

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From: Robert Haas <robertmhaas@gmail.com>
To: Peter Geoghegan <pg@bowt.ie>
Cc: Melanie Plageman <melanieplageman@gmail.com>, Andres Freund <andres@anarazel.de>, pgsql-hackers@postgresql.org
Date: 2023-02-01T13:20:12Z
Lists: pgsql-hackers 
On Tue, Jan 31, 2023 at 6:20 PM Peter Geoghegan <pg@bowt.ie> wrote:
> Actually the really wide output comes from COMMIT records. After I run
> the regression tests, and execute some of my own custom pg_walinspect
> queries, I see that some individual COMMIT records have a
> length(description) of over 10,000 bytes/characters. There is even one
> particular COMMIT record whose length(description) is about 46,000
> bytes/characters. So *ludicrously* verbose GetRmgr() strings are not
> uncommon today. The worst case (or even particularly bad cases) won't
> be made any worse by this patch, because there are obviously limits on
> the width of the arrays that it outputs details descriptions of, that
> don't apply to these COMMIT records.

If we're dumping a lot of details out of each WAL record, we might
want to switch to a multi-line format of some kind. No one enjoys a
460-character wide line, let alone 46000.

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

Commits

  1. Merge prune, freeze and vacuum WAL record formats

  2. Add rmgrdesc README

  3. Refine the guidelines for rmgrdesc authors.

  4. Fix Heap rmgr's desc output for infobits arrays.

  5. Clarify nbtree posting list update desc issue.

  6. Fix nbtree posting list update desc output.

  7. Set cutoff xmin more aggressively when vacuuming a temporary table.