Horton

Re: Show various offset arrays for heap WAL records

Melanie Plageman <melanieplageman@gmail.com>

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From: Melanie Plageman <melanieplageman@gmail.com>
To: Peter Geoghegan <pg@bowt.ie>
Cc: Andres Freund <andres@anarazel.de>, pgsql-hackers@postgresql.org, Robert Haas <robertmhaas@gmail.com>, Peter Eisentraut <peter.eisentraut@enterprisedb.com>
Date: 2023-04-11T00:23:15Z
Lists: pgsql-hackers 
On Mon, Apr 10, 2023 at 04:31:44PM -0700, Peter Geoghegan wrote:
> On Mon, Apr 10, 2023 at 3:04 PM Melanie Plageman <melanieplageman@gmail.com> wrote:
> > 
> > I will say that the prefix of p in "ptid" makes it sound like pointer to
> > a tid, which I don't believe is what you meant.
> 
> I was thinking of the symbol name "ptid" from
> _bt_delitems_delete_check() (it even appears in code comments). I
> intended "posting list TID". But "pointer to a TID" actually kinda
> works too, since these are offsets into a posting list (a simple
> ItemPointerData array) for those TIDs that we're in the process of
> removing/deleted from the tuple.

If you keep the name, I'd explain it briefly in a comment above the code
then -- for those of us who spend less time with btrees. It is a tool
that will be often used by developers, so it is not unreasonable to
assume they may read the code if they are confused.

- Melanie

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.