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Re: Make tuple deformation faster

Jeff Davis <pgsql@j-davis.com>

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From: Jeff Davis <pgsql@j-davis.com>
To: James Hunter <james.hunter.pg@gmail.com>
Cc: David Rowley <dgrowleyml@gmail.com>, Andres Freund <andres@anarazel.de>, Matthias van de Meent <boekewurm+postgres@gmail.com>, PostgreSQL Developers <pgsql-hackers@lists.postgresql.org>
Date: 2025-03-05T20:15:57Z
Lists: pgsql-hackers 
On Wed, 2025-03-05 at 11:33 -0800, James Hunter wrote:
> For a bitfield, however, the CPU has to read from or write to the
> byte
> that contains the bit, but then it also has to mask out the *other*
> bits in that bitfield. This is a data dependency, so it stalls the
> CPU
> pipeline.

Here the bits aren't changing, so we're only talking about mask-and-
test, right? My intuition is that wouldn't cause much of a problem.

Regards,
	Jeff Davis

Commits

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

  1. Fix possible Assert failure in verify_compact_attribute()

  2. Speedup tuple deformation with additional function inlining

  3. Fix race condition in TupleDescCompactAttr assert code

  4. Optimize alignment calculations in tuple form/deform

  5. Remove pg_attribute.attcacheoff column

  6. Introduce CompactAttribute array in TupleDesc, take 2

  7. Introduce CompactAttribute array in TupleDesc

  8. Use TupleDescAttr macro consistently