Fix Spark change feed hang after partition splits by tvaron3 · Pull Request #49883 · Azure/azure-sdk-for-java

tvaron3 · 2026-07-22T00:06:15Z

Description

Fixes a Spark change-feed hang that can occur when cached feed-range metadata still references a parent range after it splits. A stale-parent FromNow response can contain child continuations at different LSNs; collapsing that composite state to one scalar bound can make the lower-LSN child wait indefinitely for an unreachable end LSN.

The planner now retains the full service-issued FromNow continuation internally, expands composite state into child-specific partition metadata, and computes each child bound independently. The persisted ChangeFeedOffset v1 checkpoint model and serialization remain unchanged.

Coverage includes a unit regression for divergent child continuations and a live split regression using a deliberately stale metadata refresh interval with writes advancing only one child.

All SDK Contribution checklist:

The pull request does not introduce [breaking changes]
CHANGELOG is updated for new features, bug fixes or other significant changes.
I have read the contribution guidelines.

General Guidelines and Best Practices

Title of the pull request is clear and informative.
There are a small number of commits, each of which have an informative message. This means that previously merged commits do not appear in the history of the PR. For more information on cleaning up the commits in your PR, see this page.

Testing Guidelines

Pull request includes test coverage for the included changes.

Co-authored-by: Copilot App <223556219+Copilot@users.noreply.github.com> Copilot-Session: bf290159-a5da-42bd-ac20-662075b01169

azure-pipelines · 2026-07-22T00:07:04Z

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Co-authored-by: Copilot App <223556219+Copilot@users.noreply.github.com> Copilot-Session: bf290159-a5da-42bd-ac20-662075b01169

tvaron3 · 2026-07-22T16:19:33Z

/azp run java - cosmos - tests

azure-pipelines · 2026-07-22T16:20:11Z

Azure Pipelines: Successfully started running 1 pipeline(s).

tvaron3 · 2026-07-22T16:49:20Z

/azp run java - spark - tests

azure-pipelines · 2026-07-22T16:49:27Z

No pipelines are associated with this pull request.

tvaron3 · 2026-07-22T17:52:54Z

/azp run java - cosmos - spark

azure-pipelines · 2026-07-22T17:53:04Z

Azure Pipelines: Successfully started running 1 pipeline(s).

Co-authored-by: Copilot App <223556219+Copilot@users.noreply.github.com> Copilot-Session: bf290159-a5da-42bd-ac20-662075b01169

azure-pipelines · 2026-07-23T00:28:26Z

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tvaron3 · 2026-07-23T00:32:35Z

/azp run java - cosmos - spark

azure-pipelines · 2026-07-23T00:32:45Z

Azure Pipelines: Successfully started running 1 pipeline(s).

azure-pipelines · 2026-07-23T00:32:50Z

No pipelines are associated with this pull request.

tvaron3 · 2026-07-23T00:33:01Z

/azp run java - cosmos - tests

azure-pipelines · 2026-07-23T00:33:31Z

Azure Pipelines: Successfully started running 1 pipeline(s).

Copilot

Pull request overview

This PR fixes a Spark Cosmos change-feed hang that can occur after partition splits when cached parent feed-range metadata is stale and the service returns a composite FromNow continuation with child ranges at different LSNs. The planner now preserves and expands the composite continuation into child-specific metadata so each child is bounded independently, while keeping the persisted ChangeFeedOffset v1 model unchanged.

Changes:

Preserve the full service-issued FromNow continuation and split composite continuation state into per-effective-range PartitionMetadata.
Update the partition planner to expand composite latest metadata only for change-feed planning and to filter out-of-scope split children before planning.
Add unit + live regression coverage for divergent child continuations and stale metadata after splits; update Spark connector changelogs across supported Spark variants.

Reviewed changes

Copilot reviewed 12 out of 12 changed files in this pull request and generated 2 comments.

Show a summary per file

File	Description
sdk/cosmos/azure-cosmos-spark_4-1_2-13/CHANGELOG.md	Document the bug fix for Spark 4.1 connector variant.
sdk/cosmos/azure-cosmos-spark_4-0_2-13/CHANGELOG.md	Document the bug fix for Spark 4.0 connector variant.
sdk/cosmos/azure-cosmos-spark_3-5_2-13/CHANGELOG.md	Document the bug fix for Spark 3.5 (Scala 2.13) connector variant.
sdk/cosmos/azure-cosmos-spark_3-5_2-12/CHANGELOG.md	Document the bug fix for Spark 3.5 (Scala 2.12) connector variant.
sdk/cosmos/azure-cosmos-spark_3-4_2-12/CHANGELOG.md	Document the bug fix for Spark 3.4 connector variant.
sdk/cosmos/azure-cosmos-spark_3-3_2-12/CHANGELOG.md	Document the bug fix for Spark 3.3 connector variant.
sdk/cosmos/azure-cosmos-spark_3/src/main/scala/com/azure/cosmos/spark/PartitionMetadata.scala	Add composite continuation expansion (`splitByLatestLsn`) and propagate per-range continuation state.
sdk/cosmos/azure-cosmos-spark_3/src/main/scala/com/azure/cosmos/spark/CosmosPartitionPlanner.scala	Expand composite metadata only for change feed, and filter expanded children by feed-range scope before planning.
sdk/cosmos/azure-cosmos-spark_3/src/main/scala/com/azure/cosmos/implementation/SparkBridgeImplementationInternal.scala	Add an overload to extract continuation tokens from a parsed `ChangeFeedState`.
sdk/cosmos/azure-cosmos-spark_3/src/test/scala/com/azure/cosmos/spark/SparkE2EChangeFeedSplitITest.scala	Add a live split regression with stale metadata and time-bounded collection to catch hangs.
sdk/cosmos/azure-cosmos-spark_3/src/test/scala/com/azure/cosmos/spark/PartitionMetadataSpec.scala	Add unit coverage for composite `FromNow` continuation preservation and per-range planning.
sdk/cosmos/azure-cosmos-spark_3/src/test/scala/com/azure/cosmos/spark/CosmosPartitionPlannerSpec.scala	Add planner regressions validating expansion behavior, filtering, reconciliation, and v1 offset preservation.

Comments suppressed due to low confidence (1)

sdk/cosmos/azure-cosmos-spark_3/src/test/scala/com/azure/cosmos/spark/SparkE2EChangeFeedSplitITest.scala:327

The isPartitionKeyInRange method body is missing indentation, which makes the boolean expression harder to scan and is inconsistent with the rest of the file's formatting.

 private def isPartitionKeyInRange(
  effectiveRange: NormalizedRange,
  targetRange: NormalizedRange
 ): Boolean = {
 effectiveRange.min.compareTo(targetRange.min) >= 0 &&
  effectiveRange.min.compareTo(targetRange.max) < 0
 }

xinlian12 · 2026-07-23T18:30:45Z

@sdkReviewAgent

xinlian12

LGTM, thanks

xinlian12 · 2026-07-23T19:34:42Z

✅ Review complete (31:39)

Posted 3 inline comment(s).

_{Steps: ✓ context, correctness, cross-sdk, design, history, past-prs, synthesis, test-coverage}

Co-authored-by: Copilot App <223556219+Copilot@users.noreply.github.com> Copilot-Session: bf290159-a5da-42bd-ac20-662075b01169

tvaron3 · 2026-07-23T21:18:29Z

/azp run java - cosmos - spark

azure-pipelines · 2026-07-23T21:18:39Z

Azure Pipelines: Successfully started running 1 pipeline(s).

xinlian12

LGTM ,thanks

…ts (#49943) * Release Cosmos Spark Connectors: 4.49.2 (hotfix) Updates all azure-cosmos-spark_* packages (3.3, 3.4, 3.5 for Scala 2.12, 3.5/4.0/4.1 for Scala 2.13) to 4.49.2 as a hotfix release. Promotes the bounded change feed hang fix (PR #49883) from the Unreleased 4.50.0-beta.1 section into the 4.49.2 (2026-07-27) hotfix release across all CHANGELOGs, and updates the compatibility matrix and download coordinates in each README plus the shared quick-start doc. Co-authored-by: Copilot App <223556219+Copilot@users.noreply.github.com> * Fix stale dependency version pins in fabric-auth/sample poms Comparing against the prior Spark hotfix release (commit 808435c), these three poms depend on the released azure-cosmos-spark connector version via x-version-update/x-include-update tags and were missed in the initial hotfix commit: - fabric-cosmos-spark-auth_3/pom.xml (azure-cosmos-spark_3-5_2-12) - fabric-cosmos-spark-auth_4-0_2-13/pom.xml (azure-cosmos-spark_4-0_2-13) - azure-cosmos-spark-account-data-resolver-sample/pom.xml (azure-cosmos-spark_3-5_2-12) Co-authored-by: Copilot App <223556219+Copilot@users.noreply.github.com> --------- Co-authored-by: Copilot App <223556219+Copilot@users.noreply.github.com>

Fix Spark change feed handling after splits

806a464

Co-authored-by: Copilot App <223556219+Copilot@users.noreply.github.com> Copilot-Session: bf290159-a5da-42bd-ac20-662075b01169

github-actions Bot added the Cosmos label Jul 22, 2026

tvaron3 added 2 commits July 21, 2026 17:07

Link Spark changelogs to pull request

42bda07

Co-authored-by: Copilot App <223556219+Copilot@users.noreply.github.com> Copilot-Session: bf290159-a5da-42bd-ac20-662075b01169

Address Spark split review findings

69db2ab

Co-authored-by: Copilot App <223556219+Copilot@users.noreply.github.com> Copilot-Session: bf290159-a5da-42bd-ac20-662075b01169

Harden Spark split metadata planning

bbe4bde

Co-authored-by: Copilot App <223556219+Copilot@users.noreply.github.com> Copilot-Session: bf290159-a5da-42bd-ac20-662075b01169

tvaron3 marked this pull request as ready for review July 23, 2026 00:27

tvaron3 requested review from a team and kirankumarkolli as code owners July 23, 2026 00:27

Copilot AI review requested due to automatic review settings July 23, 2026 00:27

Copilot started reviewing on behalf of tvaron3 July 23, 2026 00:28 View session

Copilot AI reviewed Jul 23, 2026

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Comment thread ...zure-cosmos-spark_3/src/test/scala/com/azure/cosmos/spark/SparkE2EChangeFeedSplitITest.scala

Comment thread ...zure-cosmos-spark_3/src/test/scala/com/azure/cosmos/spark/SparkE2EChangeFeedSplitITest.scala

xinlian12 approved these changes Jul 23, 2026

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xinlian12 reviewed Jul 23, 2026

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Comment thread ...smos/azure-cosmos-spark_3/src/main/scala/com/azure/cosmos/spark/CosmosPartitionPlanner.scala

xinlian12 reviewed Jul 23, 2026

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Comment thread sdk/cosmos/azure-cosmos-spark_3/src/main/scala/com/azure/cosmos/spark/PartitionMetadata.scala Outdated

xinlian12 reviewed Jul 23, 2026

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Comment thread sdk/cosmos/azure-cosmos-spark_3/src/main/scala/com/azure/cosmos/spark/PartitionMetadata.scala

Address Spark split review feedback

3d653f2

Co-authored-by: Copilot App <223556219+Copilot@users.noreply.github.com> Copilot-Session: bf290159-a5da-42bd-ac20-662075b01169

xinlian12 approved these changes Jul 24, 2026

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tvaron3 merged commit e730f7f into Azure:main Jul 24, 2026
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tvaron3 commented Jul 22, 2026

Description

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