#34699: Filtering on annotated TruncSecond expression gives unexpected result.
-------------------------------------+-------------------------------------
Reporter: Stefan | Owner: Wes P.
Type: | Status: assigned
Cleanup/optimization |
Component: Database layer | Version: dev
(models, ORM) |
Severity: Normal | Resolution:
Keywords: | Triage Stage: Accepted
Has patch: 1 | Needs documentation: 0
Needs tests: 0 | Patch needs improvement: 0
Easy pickings: 0 | UI/UX: 0
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Comment (by Wes P.):
Replying to [comment:23 Jacob Walls]:
> > But then, at least to me, is quite surprising that TruncSecond, which
is an operation fully occurring in the DB, would not "respect" that "UTC
invariant" and have the TIME_ZONE setting affecting the results. Does my
point make sense? Do you have historic information about why TruncSecond
(and related functions) would not operate with/keep the tz defined in the
datetime being processed?
>
> My guess is simply that it would be a useful convenience for `USE_TZ =
False` projects, which was the ancient default. There's no reason to
expect database data to be in UTC if `TIME_ZONE = 'America/Chicago'`
(default) and `USE_TZ = False`, so you would probably want this feature:
>
When Django added TruncSecond (and related functions) the Postgres
DATE_TRUNC function was timezone naive. In 2019, Postgres added a timezone
aware feature.
> ----
> My recommendation is that we close this ticket by:
> 1. Updating the docs for `Extract()` and `Trunc()` with some nuance
> 2. Fixing the Melbourne details from comment:19
> 3. Add at least one test for `Extract` or `Trunc` with `USE_TZ = True`
and `TIME_ZONE` != `UTC` (e.g. the default `America/Chicago`)
>
> I'll review the PR with that in mind (it looks already well-scoped to
those points).
I'll await your review before making changes to the PR. Wouldn't it be
better to have a separate ticket for fixing Extract?
--
Ticket URL: <https://code.djangoproject.com/ticket/34699#comment:25>
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