Horton

Re: Show various offset arrays for heap WAL records

Peter Geoghegan <pg@bowt.ie>

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From: Peter Geoghegan <pg@bowt.ie>
To: Melanie Plageman <melanieplageman@gmail.com>
Cc: Andres Freund <andres@anarazel.de>, pgsql-hackers@postgresql.org, Robert Haas <robertmhaas@gmail.com>, Peter Eisentraut <peter.eisentraut@enterprisedb.com>
Date: 2023-04-11T18:48:18Z
Lists: pgsql-hackers

Attachments

On Tue, Apr 11, 2023 at 10:34 AM Peter Geoghegan <pg@bowt.ie> wrote:
> > description      | off: 119, xmax: 1105, flags: 0x00, old_infobits:
> > [], new off: 100, xmax 0
>
> That doesn't seem great to me either. I don't like this ambiguity,
> because it seems like it makes the description hard to parse in a way
> that flies in the face of what we're trying to do here, in general.
> So it seems like it might be worth fixing now, in the scope of this
> patch.

Attached revision deals with this by spelling out the names in full
(e.g., "old_xmax" and "new_xmax"). It also reorders the output fields
to match the order from the physical UPDATE, HOT_UPDATE, and LOCK WAL
record types, on the theory that those should match the physical
record (unless there is a good reason not to, which doesn't apply
here). I also removed some inconsistencies between
xl_heap_lock_updated and xl_heap_lock, since they're very similar
record types.

The revision also adds an extra sentence to the guidelines, since this
seems like something that we're entitled to take a relatively firm
position on. Finally, it also adds a comment about the rules for
infobits_desc callers in header comments for the function, per your
concern about that.

-- 
Peter Geoghegan

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.