Horton

Re: Parallel Bitmap Heap Scan reports per-worker stats in EXPLAIN ANALYZE

David Rowley <dgrowleyml@gmail.com>

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From: David Rowley <dgrowleyml@gmail.com>
To: Masahiro.Ikeda@nttdata.com
Cc: lena.ribackina@yandex.ru, donghanglin@gmail.com, geidav.pg@gmail.com, melanieplageman@gmail.com, tomas.vondra@enterprisedb.com, dilipbalaut@gmail.com, pgsql-hackers@lists.postgresql.org, hlinnaka@iki.fi
Date: 2024-07-08T02:47:33Z
Lists: pgsql-hackers

Commits

Same data as JSON: GET /api/v1/messages/:b64id/commits the thread's linked commits as JSON, with link sources. API reference →

  1. Show Parallel Bitmap Heap Scan worker stats in EXPLAIN ANALYZE

  2. Widen lossy and exact page counters for Bitmap Heap Scan

  3. Remove redundant snapshot copying from parallel leader to workers

On Mon, 8 Jul 2024 at 12:19, David Rowley <dgrowleyml@gmail.com> wrote:
> Notice the "Heap Blocks: exact=2250000000" is missing on Windows.
> This is because it wrapped around to a negative value and
> show_tidbitmap_info() only shows > 0 values.
>
> I feel this is a good enough justification to increase the width of
> those counters to uint64, so I'll do that too.

I pushed the widening of the types first as I saw some code in the
EXPLAIN patch which assumed var == 0 is the negator of var > 0.  I
couldn't bring myself to commit that knowing it was wrong and also
couldn't bring myself to write <= 0 knowing I was about to make that
look like a weird thing to write for an unsigned type.

David