Horton

Re: [PATCH] Optimize json_lex_string by batching character copying

John Naylor <john.naylor@enterprisedb.com>

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From: John Naylor <john.naylor@enterprisedb.com>
To: Nathan Bossart <nathandbossart@gmail.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: 2022-08-31T03:50:39Z
Lists: pgsql-hackers

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On Tue, Aug 23, 2022 at 1:03 PM John Naylor
<john.naylor@enterprisedb.com> wrote:
>
> LGTM overall. My plan is to split out the json piece, adding tests for
> that, and commit the infrastructure for it fairly soon.

Here's the final piece. I debated how many tests to add and decided it
was probably enough to add one each for checking quotes and
backslashes in the fast path. There is one cosmetic change in the
code: Before, the vectorized less-equal check compared to 0x1F, but
the byte-wise path did so with < 32. I made them both "less-equal 31"
for consistency. I'll commit this by the end of the week unless anyone
has a better idea about testing.

-- 
John Naylor
EDB: http://www.enterprisedb.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