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Short-circuit serde compatibility checks when a node is already tagged as falling back

enhancementNew feature or requestNew feature or request

performance

priority:mediumFunctional bugs, performance regressions, broken featuresFunctional bugs, performance regressions, broken features

Status: Open.

#3990 In apache/datafusion-comet;

· andygrove opened on Apr 18, 2026

[EPIC] Add support for Spark 4.0.1

enhancementNew feature or requestNew feature or request

help wantedExtra attention is neededExtra attention is needed

priority:highCrashes, panics, segfaults, major functional breakageCrashes, panics, segfaults, major functional breakage

spark 4

Status: Open.

#1637 In apache/datafusion-comet;

· andygrove opened on Apr 10, 2025

Change Comet default Spark version to 4.0

enhancementNew feature or requestNew feature or request

requires-triage

spark 4

Status: Open.

#4054 In apache/datafusion-comet;

· andygrove opened on Apr 23, 2026

Fix issues found when documenting current expression incompatibilities

bugSomething isn't workingSomething isn't working

requires-triage

Status: Open.

#4074 In apache/datafusion-comet;

· andygrove opened on Apr 24, 2026

Add tests for map types to CometFuzzTestSuite

enhancementNew feature or requestNew feature or request

Status: Open.

#1665 In apache/datafusion-comet;

· andygrove opened on Apr 21, 2025

Add support for size expression

enhancementNew feature or requestNew feature or request

expressionSpark expression relatedSpark expression related

Status: Open.

#1926 In apache/datafusion-comet;

· andygrove opened on Jun 23, 2025

Reinstate macOS CI builds of Comet with Spark 4.0.0

enhancementNew feature or requestNew feature or request

spark 4

Status: Open.

#1949 In apache/datafusion-comet;

· andygrove opened on Jun 27, 2025

[EPIC] Iceberg compatibility fixes

enhancementNew feature or requestNew feature or request

EPIC

Status: Open.

#2060 In apache/datafusion-comet;

· andygrove opened on Aug 1, 2025

[iceberg] Iceberg data files not found when Comet vectorized reader is enabled

area:scanParquet scan / data readingParquet scan / data reading

bugSomething isn't workingSomething isn't working

priority:mediumFunctional bugs, performance regressions, broken featuresFunctional bugs, performance regressions, broken features

Status: Open.

#2116 In apache/datafusion-comet;

· hsiang-c opened on Aug 11, 2025

Custom Authentication & External File Systems

enhancementNew feature or requestNew feature or request

Status: Open.

#2341 In apache/datafusion-comet;

· andygrove opened on Sep 8, 2025

Add support for Spark 4.0.x + Iceberg 1.9.x

enhancementNew feature or requestNew feature or request

spark 4

Status: Open.

#2380 In apache/datafusion-comet;

· andygrove opened on Sep 11, 2025

[hdfs-opendal] Got an reader got too little data error on hdfs-opendal

area:scanParquet scan / data readingParquet scan / data reading

bugSomething isn't workingSomething isn't working

native_datafusionSpecific to native_datafusion scan typeSpecific to native_datafusion scan type

priority:mediumFunctional bugs, performance regressions, broken featuresFunctional bugs, performance regressions, broken features

Status: Open.

#2400 In apache/datafusion-comet;

· wForget opened on Sep 16, 2025

Improve documentation for configs related to explain/fallback

documentationImprovements or additions to documentationImprovements or additions to documentation

enhancementNew feature or requestNew feature or request

good first issueGood for newcomersGood for newcomers

Status: Open.

#2413 In apache/datafusion-comet;

· andygrove opened on Sep 17, 2025

Release build script builds JVM components from wrong branch

area:ciCI/CD, GitHub Actions, build toolingCI/CD, GitHub Actions, build tooling

bugSomething isn't workingSomething isn't working

priority:lowMinor issues, test failures, tooling, cosmeticMinor issues, test failures, tooling, cosmetic

Status: Open.

#3292 In apache/datafusion-comet;

· andygrove opened on Jan 26, 2026

Mismatch in Data Types Between Partial and Final Stages in Aggregations

area:aggregationHash aggregates, aggregate expressionsHash aggregates, aggregate expressions

bugSomething isn't workingSomething isn't working

priority:criticalData corruption, silent wrong results, security issuesData corruption, silent wrong results, security issues

Status: Open.

#1287 In apache/datafusion-comet;

· andygrove opened on Jan 14, 2025

AQE may materialize a non-supported Final-mode HashAggregate

area:aggregationHash aggregates, aggregate expressionsHash aggregates, aggregate expressions

bugSomething isn't workingSomething isn't working

priority:criticalData corruption, silent wrong results, security issuesData corruption, silent wrong results, security issues

Status: Open.

#1389 In apache/datafusion-comet;

· EmilyMatt opened on Feb 12, 2025

Implement zero-copy FFI transfer of batches from JVM to Native

enhancementNew feature or requestNew feature or request

Status: Open.

#2171 In apache/datafusion-comet;

· andygrove opened on Aug 17, 2025

ExecutionMemoryPool errors releasing more memory than allocated

bugSomething isn't workingSomething isn't working

priority:highCrashes, panics, segfaults, major functional breakageCrashes, panics, segfaults, major functional breakage

Status: Open.

#2453 In apache/datafusion-comet;

· andygrove opened on Sep 25, 2025

Dropping a GlobalRef in a detached thread

area:ffiArrow FFI / JNI boundaryArrow FFI / JNI boundary

bugSomething isn't workingSomething isn't working

priority:highCrashes, panics, segfaults, major functional breakageCrashes, panics, segfaults, major functional breakage

Status: Open.

#2470 In apache/datafusion-comet;

· andygrove opened on Sep 26, 2025

[EPIC] Improve awslabs published results for Comet w/ TPC-DS

enhancementNew feature or requestNew feature or request

performance

Status: Open.

#3799 In apache/datafusion-comet;

· andygrove opened on Mar 26, 2026

Shuffle memory pool accounting: peak RSS significantly exceeds configured memory limit

area:shuffleShuffle (JVM and native)Shuffle (JVM and native)

Status: Open.

#3821 In apache/datafusion-comet;

· andygrove opened on Mar 27, 2026

Explore zero-copy batch coalescing during shuffle write

area:shuffleShuffle (JVM and native)Shuffle (JVM and native)

performance

Status: Open.

#3836 In apache/datafusion-comet;

· andygrove opened on Mar 29, 2026

Spark cannot reclaim memory from native operators (spill callback returns 0)

performance

priority:highCrashes, panics, segfaults, major functional breakageCrashes, panics, segfaults, major functional breakage

Status: Open.

#3873 In apache/datafusion-comet;

· andygrove opened on Apr 1, 2026

Current shuffle format has too much overhead with default batch size

area:shuffleShuffle (JVM and native)Shuffle (JVM and native)

bugSomething isn't workingSomething isn't working

performance

priority:highCrashes, panics, segfaults, major functional breakageCrashes, panics, segfaults, major functional breakage

Status: Open.

#3882 In apache/datafusion-comet;

· andygrove opened on Apr 2, 2026

Avoid FFI import/export when passing batches between two native plans

area:ffiArrow FFI / JNI boundaryArrow FFI / JNI boundary

area:shuffleShuffle (JVM and native)Shuffle (JVM and native)

enhancementNew feature or requestNew feature or request

performance

Status: Open.

#3925 In apache/datafusion-comet;

· andygrove opened on Apr 10, 2026