mirror of
https://github.com/GreptimeTeam/greptimedb.git
synced 2026-10-13 07:22:32 +00:00
DeviousCardi
ffbbae7acf
* 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>
Sqlness Test
Sqlness manual
Case file
Sqlness has two types of file:
.sql: test input, SQL only.result: expected test output, SQL and its results
.result is the output (execution result) file. If you see .result files is changed,
it means this test gets a different result and indicates it fails. You should
check change logs to solve the problem.
You only need to write test SQL in .sql file, and run the test.
Case organization
The root dir of input cases is tests/cases. It contains several subdirectories stand for different test
modes. E.g., standalone/ contains all the tests to run under greptimedb standalone start mode.
Under the first level of subdirectory (e.g. the cases/standalone), you can organize your cases as you like.
Sqlness walks through every file recursively and runs them.
Kafka WAL
Sqlness supports Kafka WAL. You can either provide a Kafka cluster or let sqlness to start one for you.
To run test with kafka, you need to pass the option -w kafka. If no other options are provided, sqlness will use conf/kafka-cluster.yml to start a Kafka cluster. This requires docker and docker-compose commands in your environment.
Otherwise, you can additionally pass the your existing kafka environment to sqlness with -k option. E.g.:
cargo sqlness bare -w kafka -k localhost:9092
In this case, sqlness will not start its own kafka cluster and the one you provided instead.
Run the test
Unlike other tests, this harness is in a binary target form. You can run it with:
cargo sqlness bare
It automatically finishes the following procedures: compile GreptimeDB, start it, grab tests and feed it to
the server, then collect and compare the results. You only need to check if the .result files are changed.
If not, congratulations, the test is passed 🥳!