Re: [POC] verifying UTF-8 using SIMD instructions

John Naylor <john.naylor@enterprisedb.com>

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From: John Naylor <john.naylor@enterprisedb.com>

To: Heikki Linnakangas <hlinnaka@iki.fi>

Cc: pgsql-hackers <pgsql-hackers@postgresql.org>

Date: 2021-02-07T20:24:16Z

Lists: pgsql-hackers

Attachments

v1-0001-Add-an-ASCII-fast-path-to-multibyte-encoding-veri.patch (application/octet-stream) patch v1-0001

Here is a more polished version of the function pointer approach, now
adapted to all multibyte encodings. Using the not-yet-committed tests from
[1], I found a thinko bug that resulted in the test for nul bytes to not
only be wrong, but probably also elided by the compiler. Doing it correctly
is noticeably slower on pure ascii, but still several times faster than
before, so the conclusions haven't changed any. I'll run full measurements
later this week, but I'll share the patch now for review.

[1]
https://www.postgresql.org/message-id/11d39e63-b80a-5f8d-8043-fff04201fadc@iki.fi

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

Commits

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

Simplify coding style of is_valid_ascii()
- 6b41a1579bd3 16.0 landed
Apply auto-vectorization to the inner loop of numeric multiplication.
- 88709176236c 14.0 cited