Inf1mum opened a new pull request, #27381: URL: https://github.com/apache/datafusion/pull/27381
## Which issue does this PR close? - Closes #25168. ## Rationale for this change An explicit `origin_timestamp` chosen to align `date_bin` bins to local midnight works until the timezone's offset changes, then silently shifts the bins by an hour. There is no error and no warning. This is not a bug in DataFusion — PostgreSQL and DuckDB return identical results, because all three bin on the instant measured from a fixed origin — but the pattern looks correct in every test that does not cross a DST transition, so the issue asks for it to be documented. ## What changes are included in this PR? Adds a short note to the `date_bin` documentation: an explicit origin fixes an instant, not a recurring local time, so bins aligned to local midnight with an origin silently shift by an hour across a daylight saving time transition. It points users at `date_trunc` for calendar units, and at `date_bin(<stride>, to_local_time(t AT TIME ZONE '<zone>'))` for strides that are not calendar units. The note is added to the rustdoc in `datafusion/functions/src/datetime/date_bin.rs` and mirrored into `docs/source/user-guide/sql/scalar_functions.md` (which `dev/update_function_docs.sh` regenerates from the rustdoc). ## What is the testing strategy for this PR? Docs-only change; no code or test behaviour is touched. - `cargo test -p datafusion-functions --lib` — 410 passed, 0 failed. - `cargo fmt --check` on the touched crate. ## Are there any user-facing changes? Documentation only. No behaviour change, no public API change. -- This is an automated message from the Apache Git Service. To respond to the message, please log on to GitHub and use the URL above to go to the specific comment. To unsubscribe, e-mail: [email protected] For queries about this service, please contact Infrastructure at: [email protected] --------------------------------------------------------------------- To unsubscribe, e-mail: [email protected] For additional commands, e-mail: [email protected]
