Horton

Re: [PATCH] Optimize json_lex_string by batching character copying

Nathan Bossart <nathandbossart@gmail.com>

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From: Nathan Bossart <nathandbossart@gmail.com>
To: John Naylor <john.naylor@enterprisedb.com>
Cc: Andres Freund <andres@anarazel.de>, Tom Lane <tgl@sss.pgh.pa.us>, Jelte Fennema <Jelte.Fennema@microsoft.com>, "pgsql-hackers@postgresql.org" <pgsql-hackers@postgresql.org>, Merlin Moncure <mmoncure@gmail.com>, Andrew Dunstan <andrew.dunstan@2ndquadrant.com>, Stephen Frost <sfrost@snowman.net>
Date: 2022-08-19T20:42:15Z
Lists: pgsql-hackers 
On Fri, Aug 19, 2022 at 03:11:36PM +0700, John Naylor wrote:
> This is done. Also:
> - a complete overhaul of the pg_lfind8* tests
> - using a typedef for the vector type
> - some refactoring, name changes and other cleanups (a few of these
> could also be applied to the 32-byte element path, but that is left
> for future work)
> 
> TODO: json-specific tests of the new path

This looks pretty good to me.  Should we rename vector_broadcast() and
vector_has_zero() to indicate that they are working with bytes (e.g.,
vector_broadcast_byte())?  We might be able to use vector_broadcast_int()
in the 32-bit functions, and your other vector functions already have a
_byte suffix.

In general, the approach you've taken seems like a decent readability
improvement.  I'd be happy to try my hand at adjusting the 32-bit path and
adding ARM versions of all this stuff.

-- 
Nathan Bossart
Amazon Web Services: https://aws.amazon.com

Commits

  1. Speed up lexing of long JSON strings

  2. Add optimized functions for linear search within byte arrays

  3. Build de-escaped JSON strings in larger chunks during lexing

  4. Simplify json lexing state