Horton

Re: Add support for AT LOCAL

Michael Paquier <michael@paquier.xyz>

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From: Michael Paquier <michael@paquier.xyz>
To: Tom Lane <tgl@sss.pgh.pa.us>
Cc: Noah Misch <noah@leadboat.com>, Thomas Munro <thomas.munro@gmail.com>, Vik Fearing <vik@postgresfriends.org>, cary huang <hcary328@gmail.com>, pgsql-hackers@lists.postgresql.org
Date: 2023-10-18T00:02:13Z
Lists: pgsql-hackers 
On Tue, Oct 17, 2023 at 12:45:28PM -0400, Tom Lane wrote:
> Whoops, no: for negative starting values we'd need truncate-towards-
> minus-infinity division whereas C99 specifies truncate-towards-zero.
> However, the attached does pass for me on cfarm111 as well as my
> usual dev machine.

I guess that the following trick could be used for the negative case,
with one modulo followed by one extra addition: 
if (result->time < INT64CONST(0))
{
    result->time %= USECS_PER_DAY;
    result->time += USECS_PER_DAY;
}

> Presumably this is a pre-existing bug that also appears in back
> branches.  But in the interests of science I propose that we
> back-patch only the test case and see which machine(s) fail it
> before back-patching the code change.

Sure, as you see fit.
--
Michael

Commits

  1. Dodge a compiler bug affecting timetz_zone/timetz_izone.

  2. Back-patch test cases for timetz_zone/timetz_izone.

  3. Add regression test coverage for timetz_izone().

  4. Add support for AT LOCAL

  5. doc: Mention timezone(zone, time) in section for AT TIME ZONE

  6. Use HASH_BLOBS for xidhash.