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: 2022-08-23T17:15:46Z
Lists: pgsql-hackers 
On Tue, Aug 23, 2022 at 01:03:03PM +0700, John Naylor wrote:
> On Tue, Aug 23, 2022 at 10:32 AM Nathan Bossart
>> Here's a new version of the patch with the 32-bit changes and calls to
>> lfind() removed.
> 
> LGTM overall. My plan is to split out the json piece, adding tests for
> that, and commit the infrastructure for it fairly soon. Possible
> bikeshedding: Functions like vector8_eq() might be misunderstood as
> comparing two vectors, but here we are comparing each lane with a
> scalar. I wonder if vector8_eq_scalar() et al might be more clear.

Good point.  I had used vector32_veq() to denote vector comparison, which
would extend to something like vector8_seq().  But that doesn't seem
descriptive enough.  It might be worth considering vector8_contains() or
vector8_has() as well.  I don't really have an opinion, but if I had to
pick something, I guess I'd choose vector8_contains().

-- 
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