1.2.0

Issues

• Sort-aware Iceberg reads: per-partition streaming merge + report ordering and grouping (v1)

  area:scanenhancement
  apache/datafusion-comet#5337 · Filter by author parthchandra opened on Aug 12, 2026 · 1.2.0
  

• Merge on sort keys even when they are not selected

  area:scanenhancement
  apache/datafusion-comet#5338 · Filter by author parthchandra opened on Aug 12, 2026 · 1.2.0
  

• Support transformed sort orders (bucket / truncate / etc.)

  area:scanenhancement
  apache/datafusion-comet#5339 · Filter by author parthchandra opened on Aug 12, 2026 · 1.2.0
  

• Keep read concurrency in the sorted merge path

  area:scanenhancement
  apache/datafusion-comet#5340 · Filter by author parthchandra opened on Aug 12, 2026 · 1.2.0
  

• Skip the merge wrapper for single-file partitions

  area:scanenhancement
  apache/datafusion-comet#5341 · Filter by author parthchandra opened on Aug 12, 2026 · 1.2.0
  

• Broaden storage-partitioned-join tests, then enable reportPartitioning by default

  area:scanenhancement
  apache/datafusion-comet#5342 · Filter by author parthchandra opened on Aug 12, 2026 · 1.2.0
  

• Bound memory when a partition has many files

  area:scanenhancement
  apache/datafusion-comet#5343 · Filter by author parthchandra opened on Aug 12, 2026 · 1.2.0
  

• Sort-aware Iceberg reads in Comet via a per-partition streaming merge

  area:scanenhancementrun-iceberg-testsrun-spark-4.1-tests
  Feature

  apache/datafusion-comet#5323 · Filter by author parthchandra opened on Aug 10, 2026 · 1.2.0
  

• Codify Iceberg version compatibility

  area:ciarea:Icebergenhancement
  apache/datafusion-comet#4871 · Filter by author mbutrovich opened on Jul 9, 2026 · 1.2.0
  3

  

• Parquet reader: Add support for reading row index metadata columns

  enhancementnative_datafusion
  apache/datafusion-comet#3432 · Filter by author andygrove opened on Feb 6, 2026 · 1.2.0
  3

  

• array_append: ANSI item error is swallowed when the array is NULL

  area:expressionsbackport-1.1bugcorrectnesspriority:critical
  apache/datafusion-comet#6086 · Filter by author andygrove opened on Sep 21, 2026 · 1.2.0
  

• Codegen dispatcher writes a null map key as the key type's default value

  area:expressionsbugpriority:critical
  apache/datafusion-comet#6172 · Filter by author Smallfu666 opened on Sep 24, 2026 · 1.2.0
  1

  

• AQE reuses one exchange for scans with different dynamic pruning filters and drops rows

  area:scanbugcorrectnesspriority:critical
  apache/datafusion-comet#6264 · Filter by author dwsmith1983 opened on Sep 27, 2026 · 1.2.0
  6

  

• Do not accelerate a query stage that contains a columnar-to-row fallback (enable whole-stage revert by default)

  enhancementperformanceuser experience
  apache/datafusion-comet#5207 · Filter by author andygrove opened on Aug 1, 2026 · 1.2.0
  

• Comet 1.1.0 Release (September)

  enhancement
  apache/datafusion-comet#5327 · Filter by author andygrove opened on Aug 11, 2026 · 1.2.0
  12

  

• NegativeExpr::get_properties reports child ordering and range unchanged

  area:expressionsbugpriority:medium
  apache/datafusion-comet#5330 · Filter by author Smallfu666 opened on Aug 11, 2026 · 1.2.0
  1

  

• Use end to end microbenchmarks to prevent performance regressions between releases

  area:cienhancement
  apache/datafusion-comet#5373 · Filter by author andygrove opened on Aug 15, 2026 · 1.2.0
  

• Incorrect AVG result from empty native partial buffers

  area:aggregationbugpriority:critical
  apache/datafusion-comet#5418 · Filter by author sunchao opened on Aug 22, 2026 · 1.2.0

• Date-to-timestamp casts can overflow or panic for wide dates

  area:expressionsbugcorrectnesspriority:critical
  apache/datafusion-comet#5456 · Filter by author sunchao opened on Aug 24, 2026 · 1.2.0
  

• Match Spark ObjectHashAggregate decimal AVG buffer semantics

  area:aggregationbugpriority:critical
  apache/datafusion-comet#5509 · Filter by author sunchao opened on Aug 27, 2026 · 1.2.0
  

• Checked TIMESTAMP_MILLIS overflow for nested fields and nested-predicate scans is blocked on DataFusion nested-field pruning

  area:scanbugcorrectnesspriority:critical
  apache/datafusion-comet#5553 · Filter by author peterxcli opened on Aug 29, 2026 · 1.2.0
  2

  

• [EPIC] DataFusion 55 upgrade follow-ups

  enhancementEPIC
  apache/datafusion-comet#5709 · Filter by author andygrove opened on Sep 5, 2026 · 1.2.0
  3

• Track nested-field statistics pruning and TIMESTAMP_MILLIS overflow parity in filtered scans

  area:scanbugpriority:critical
  apache/datafusion-comet#5739 · Filter by author peterxcli opened on Sep 6, 2026 · 1.2.0
  2

  

• size, arrays_zip, map_from_arrays and array_append return wrong answers for a nondeterministic child

  area:expressionsarray expressionsbugcorrectnessmap expressionspriority:critical
  apache/datafusion-comet#5781 · Filter by author andygrove opened on Sep 8, 2026 · 1.2.0
  4

  

• perf: broadcast hash join rebuilds the build-side hash table in every task

  enhancementperformance
  apache/datafusion-comet#6013 · Filter by author andygrove opened on Sep 18, 2026 · 1.2.0
  2