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* fix(promql): apply offset to subquery evaluation window `prom_subquery_expr_to_plan` destructured `SubqueryExpr` without reading `offset`, so `<subquery>[range:step] offset <d>` planned exactly the same window as the un-offset form and silently returned data for the wrong time range. The plain vector/matrix-selector paths already threaded the offset through `selector_to_series_normalize_plan` and `RangeManipulate`. Shift the inner evaluation window back by the offset and pass the offset to the subquery's `RangeManipulate`, which maps the inner samples forward onto the evaluation timeline before bucketing them into ranges. This matches Prometheus, whose `evaluator.subqueryTimeRange` evaluates the inner expression over `(start - offset - range, end - offset]` and whose `evalSubquery` then hands the samples to the outer range-vector function as a `MatrixSelector` that still carries the subquery offset. An offset on the inner selector composes additively, as `subqueryTimes` documents. `RangeManipulate`'s protobuf message has no offset field and recovers it on decode from an immediately underlying `SeriesNormalize`. Since `RangeManipulate` is commutative in `dist_plan` and can be pushed below a `MergeScan`, insert that carrier node so the offset survives distributed planning instead of decoding as zero. Known divergence, unchanged by this commit: Prometheus anchors subquery step points on absolute epoch multiples of the step, while GreptimeDB anchors them on the evaluation start. The two agree whenever the offset is a multiple of the subquery step; the added sqlness cases stay within that range. Closes #9330 Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com> Signed-off-by: Aarav <aaravsjadav@gmail.com> * docs(promql): correct the subquery-offset rationale and pin the histogram shift Follow-up toe132c267, which stated two things inaccurately and left one path untested. No behaviour change beyond a conditional clone. The `SeriesNormalize` carrier was described as existing "so the offset survives distributed planning", implying standalone is unaffected. That is wrong. `local_offset` is read on the substrait decode path (`range_manipulate.rs`, `instant_manipulate.rs`), and GreptimeDB routes PromQL plans through `MergeScan`/substrait in standalone too -- the standalone results `promql/encode_substrait.result` and `precisions.result` both show `MergeScan [is_placeholder=false, remote_input=[...]]`. Deleting the carrier therefore empties subquery-with-offset results in standalone as well, while `count_over_time_subquery_with_offset` keeps passing because it asserts the pre-serialization plan. Say so at the node, so the next reader does not remove it believing standalone is safe. The carrier is also not semantically inert: `SeriesNormalizeStream::normalize` shifts native histogram `start_timestamp` payloads by `offset`. On the subquery path that runs on a computed inner result, on top of any offset the inner selector already applied, and nothing pinned it. It is consistent -- `RangeManipulate` moves the millisecond time index forward by the same `offset_ms` -- so the distance from a histogram's start timestamp to the sample carrying it, which reset/rate detection reads, is invariant. Add `subquery_offset_shifts_histogram_start_and_time_index_together`, which executes the subquery's node stack over native histogram samples for a zero and a non-zero inner offset. It cannot be a sqlness case: native histograms are a struct column with no SQL type or literal (`sql_data_type_to_concrete_data_type` rejects structs) and the sqlness runner speaks only MySQL/Postgres, so such rows only arrive over gRPC/remote-write v2. The divergence note blamed sub-step offsets. Measured, that condition is too narrow: an unaligned evaluation timestamp alone diverges, with no offset at all -- `sum_over_time(fine[20s:10s])` at t=57 samples 47s and 57s here against Prometheus's 40s and 50s. The real condition is that `(start - offset)` is not a multiple of the subquery step, and it is pre-existing: the committed `tql eval (359, 359, '1s') sum_over_time(metric_total[60s:10s])` case is already an instance of it (`359 - 60 + 10 = 309`). Reword the comment and the sqlness header accordingly. A sub-step offset stays accepted: `foo[20s:10s] offset 5s` is valid PromQL, erroring on it would be a regression and would not close the gap anyway. This repo has no PromQL-compatibility documentation page, so there is nowhere else to record it. Also stop cloning the series key columns when there is no offset, and stop the `offset 0s` sqlness comment implying its parser error is evidence about this fix -- the same message comes from a `u32` overflow in `promql-parser`'s shared duration check (`offset 9999999999d`). Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com> Signed-off-by: Aarav <aaravsjadav@gmail.com> * refactor(promql): trim subquery-offset comments and tests per review Shorten the planner and sqlness comments to the semantic contract, build `SeriesDivide` with a clone instead of an `Option`, and drop the normalize.rs histogram test and the `offset 0s` parser case. Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com> Claude-Session: https://claude.ai/code/session_01Bvab9gpXYjKyLN8Mo6JWWL Signed-off-by: Aarav <aaravsjadav@gmail.com> * fix(promql): record the subquery offset as the range fold offset The subquery's `RangeManipulate` now shifts the payload timestamps by the offset, so `predict_linear` over an offset subquery must recover the evaluation time with that offset instead of 0. Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com> Claude-Session: https://claude.ai/code/session_01Bvab9gpXYjKyLN8Mo6JWWL Signed-off-by: Aarav <aaravsjadav@gmail.com> --------- Signed-off-by: Aarav <aaravsjadav@gmail.com> Co-authored-by: Claude Opus 5 (1M context) <noreply@anthropic.com> (cherry picked from commitd6474b961c) Signed-off-by: WenyXu <wenymedia@gmail.com>