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Posted to issues@flink.apache.org by "imankhadiv (via GitHub)" <gi...@apache.org> on 2026/08/26 15:47:00 UTC

[PR] [FLINK-40232][table-runtime] Handle null rowtime in OutputConversionOperator [flink]

imankhadiv opened a new pull request, #29027:
URL: https://github.com/apache/flink/pull/29027

   ## What is the purpose of the change
   
   `OutputConversionOperator.processElement` dereferences the result of `RowData#getTimestamp(...)` without a null check, so converting a table with a `null` rowtime attribute into a `DataStream` fails the job with a `NullPointerException`. Both rowtime paths are affected: the rowtime metadata path and the rowtime column path.
   
   Adding null checks alone is not enough. `outRecord` is a single `StreamRecord` allocated once in `open()` and reused for every element, and `StreamRecord#replace(Object)` leaves the timestamp untouched. Merely skipping `setTimestamp()` would leave the *previous* record's timestamp on the record carrying the null rowtime, i.e. it would trade the `NullPointerException` for a silently wrong timestamp. The null case therefore erases the timestamp explicitly.
   
   ## Brief change log
   
     - Both rowtime lookups in `OutputConversionOperator` go through a new private `updateRowtime(RowData, int)` helper
     - The helper sets the output timestamp when the rowtime is present, and calls `StreamRecord#eraseTimestamp()` when it is null, so a record with a null rowtime cannot inherit the preceding record's timestamp
   
   ## Verifying this change
   
   This change added tests and can be verified as follows:
   
     - Added `OutputConversionOperatorTest` with four cases — a null rowtime is emitted without a timestamp, and a null rowtime does not inherit the timestamp of the preceding record — each covering the rowtime metadata path and the rowtime column path
     - All four tests were watched failing before the fix: first with the reported `NullPointerException`, and the two "does not inherit" cases again against a null-check-only variant of the fix, which is what motivated the explicit `eraseTimestamp()`
     - `flink-table-runtime` module test suite passes (1824 tests)
     - `DataStreamJavaITCase` passes (38 tests); it covers the non-null rowtime path end to end via `toDataStream` with event-time windows and a downstream assertion on `ctx.timestamp()`
   
   ## Does this pull request potentially affect one of the following parts:
   
     - Dependencies (does it add or upgrade a dependency): **no**
     - The public API, i.e., is any changed class annotated with `@Public(Evolving)`: **no**
     - The serializers: **no**
     - The runtime per-record code paths (performance sensitive): **yes** — one additional `isNullAt` check per record, in an operator that already read the rowtime field
     - Anything that affects deployment or recovery: JobManager (and its components), Checkpointing, Kubernetes/Yarn, ZooKeeper: **no**
     - The S3 file system connector: **no**
   
   ## Documentation
   
     - Does this pull request introduce a new feature? **no**
     - If yes, how is the feature documented? **not applicable**
   
   ---
   
   ##### Was generative AI tooling used to co-author this PR?
   
   - [X] Yes (please specify the tool below)
   
   Generated-by: Claude Code (Claude Opus 5)
   


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