Issues

• Native CASE WHEN and COALESCE reconcile struct fields by name instead of position

  bugcorrectnessrequires-triage
  apache/datafusion-comet#6532 · Filter by author andygrove opened on Oct 1, 2026

• AQE skew join split makes the join fall back to Spark with no fallback reason

  performancerequires-triage
  apache/datafusion-comet#6530 · Filter by author comphead opened on Oct 1, 2026
  

• perf: Comet hash joins use more task time than Spark (skewed SHJ with nested payload, BHJ)

  performancerequires-triage
  apache/datafusion-comet#6528 · Filter by author comphead opened on Oct 1, 2026
  

• Reduce retained buffer allocation when map lookups select short nested values

  area:expressionsbugpriority:mediumrequires-triage
  apache/datafusion-comet#6525 · Filter by author andygrove opened on Oct 1, 2026

• Native Iceberg sorted-merge scan rebuilds the delete-file cache per file (shared deletes re-read)

  bug
  apache/datafusion-comet#6524 · Filter by author parthchandra opened on Oct 1, 2026
  

• Clarify how to run native Comet -> Celeborn shuffle end-to-end

  requires-triage
  apache/datafusion-comet#6523 · Filter by author unikdahal opened on Oct 1, 2026
  3

• signum(-0.0) returns 0.0 instead of -0.0

  bugrequires-triage
  apache/datafusion-comet#6522 · Filter by author andygrove opened on Oct 1, 2026

• Run array_contains on float elements natively with Spark's equality instead of through the codegen dispatcher

  enhancementrequires-triage
  apache/datafusion-comet#6520 · Filter by author andygrove opened on Oct 1, 2026

• percentile_approx returns different percentiles from Spark when its input holds a NaN with the sign bit set

  bugrequires-triage
  apache/datafusion-comet#6519 · Filter by author andygrove opened on Oct 1, 2026

• Support native existence sort-merge joins

  requires-triage
  apache/datafusion-comet#6514 · Filter by author coderfender opened on Oct 1, 2026
  

• Native Parquet scan assigns row groups to splits differently from Spark

  area:scanenhancementrequires-triage
  apache/datafusion-comet#6512 · Filter by author andygrove opened on Oct 1, 2026 · 1.2.0
  

• S3 credential SPI: honor expirationEpochMillis consistently on the Parquet and Iceberg paths

  requires-triage
  apache/datafusion-comet#6508 · Filter by author snmvaughan opened on Oct 1, 2026

• Native Iceberg scan fails on files written before a nested field was added, and since 1.1.0 null checks and explode hit it too

  area:Icebergbugregressionrequires-triage
  apache/datafusion-comet#6504 · Filter by author andygrove opened on Oct 1, 2026
  

• Experimental local execution mode that runs a whole query as one DataFusion graph

  enhancementrequires-triage
  apache/datafusion-comet#6499 · Filter by author viirya opened on Oct 1, 2026

• Assess native (Rust) code generation for fused expression evaluation

  area:expressionsenhancementperformancerequires-triage
  apache/datafusion-comet#6485 · Filter by author comphead opened on Oct 1, 2026
  

• Native existence join enumerates every duplicate build match (N*M candidates for M markers)

  requires-triage
  apache/datafusion-comet#6484 · Filter by author coderfender opened on Sep 30, 2026
  1

  

• Native CASE WHEN names its struct result's fields after the ELSE branch instead of the first THEN branch

  bugcorrectnessrequires-triage
  apache/datafusion-comet#6482 · Filter by author andygrove opened on Sep 30, 2026
  2

  

• Native corr, covariance, variance and stddev return wrong values for a constant fractional column merged from several partitions

  bugcorrectnessrequires-triage
  apache/datafusion-comet#6481 · Filter by author andygrove opened on Sep 30, 2026

• RANGE window frames over an array or struct key with a null element span the whole partition

  bugrequires-triage
  apache/datafusion-comet#6477 · Filter by author andygrove opened on Sep 30, 2026

• Native sort orders null elements of array and struct keys by the key's null order, unlike Spark

  bugrequires-triage
  apache/datafusion-comet#6476 · Filter by author andygrove opened on Sep 30, 2026

• array_contains, arrays_overlap, array_distinct and array_union ignore string collation

  bugrequires-triage
  apache/datafusion-comet#6470 · Filter by author viirya opened on Sep 30, 2026

• Investigate nested TPC-H q21 slowdown: Comet 37% slower than Spark at SF1000

  performancerequires-triage
  apache/datafusion-comet#6467 · Filter by author comphead opened on Sep 30, 2026
  3

  

• Trying to reduce CI time

  requires-triage
  apache/datafusion-comet#6465 · Filter by author rluvaton opened on Sep 30, 2026

• The SQL tab and event log lose the cached plan under CometInMemoryTableScan

  bugpriority:lowrequires-triage
  apache/datafusion-comet#6463 · Filter by author andygrove opened on Sep 30, 2026
  2

• S3 credential SPI: per-location credentials for native Iceberg reads and writes

  requires-triage
  apache/datafusion-comet#6462 · Filter by author snmvaughan opened on Sep 30, 2026
  1