apache/datafusion

Apache DataFusion SQL Query Engine

Stars: 9.3k
Forks: 2.4k
Open beginner issues: 0
Indexed issues: 1.8k
Avg merge: 3d 6h
Merged PRs (30d): 363

Dominant language: Rust
License: Apache-2.0
Last GitHub push: Sep 19, 2026
Latest indexed: Sep 14, 2026
Contributing guide: Contributing guide
Code of conduct: Code of conduct
Beginner labels: good first issue help wanted

Beginner friendly Everything

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1,802 open issues indexed

Implement dynamic discrete pruning through a join Open

enhancement

Difficulty 5/5 Over a week Newbie friendliness 45/100

apache/datafusion#25291 · Opened Sep 14, 2026
Correlated `EXISTS` subquery with `OFFSET` returns wrong results Open

bug

Difficulty 4/5 3-5 days Newbie friendliness 58/100

apache/datafusion#25283 · Opened Sep 14, 2026
panic: GROUP BY or SELECT DISTINCT over a zero-field (empty) struct key Open

bug

Difficulty 3/5 1-2 days Newbie friendliness 76/100

apache/datafusion#25281 · Opened Sep 13, 2026
Track PR release version with labels/milestones Open

apache/datafusion#25280 · 1 assignee · Opened Sep 13, 2026
`RewriteSetComparison` is overly aggressive rewriting some set comparison into multiple mark joins Open

apache/datafusion#25276 · 2 comments · 1 assignee · Opened Sep 13, 2026
SortPreservingMerge over-reserves memory by orders of magnitude for Utf8View sort keys: reservation measured before gc(), causing spurious ResourcesExhausted Open

bug

apache/datafusion#25271 · 1 assignee · Opened Sep 13, 2026
PiecewiseMergeJoin classic join materializes O(buffered_len) intermediate batches with no memory accounting on the output path Open

bug

apache/datafusion#25270 · 1 assignee · Opened Sep 13, 2026
CollectLeft hash join build holds ~2x build side while charging the memory pool 1x: concat_batches copy is never reserved and superseded batches are never shrunk Open

bug

apache/datafusion#25269 · 1 assignee · Opened Sep 13, 2026
Wrong results: filter marked as pushed down at plan time can be silently dropped per-file when schema evolution makes the runtime pushdown checker reject the adapted predicate Open

bug

apache/datafusion#25268 · 1 assignee · Opened Sep 13, 2026
`percentile_cont` overflows while interpolating finite Float64 values Open

bug

Difficulty 3/5 1-2 days Newbie friendliness 76/100

apache/datafusion#25267 · 2 comments · Opened Sep 13, 2026
`percentile_cont` truncates Float64 interpolation weights to six decimal places Open

bug

Difficulty 2/5 1-3 hours Newbie friendliness 82/100

apache/datafusion#25266 · 2 comments · Opened Sep 13, 2026
When performing set comparison subqueries (such as > ANY / > ALL / = ANY, etc.) on the same table (without using aliases), silently returns wrong results (0 rows or all rows). Open

apache/datafusion#25258 · 5 comments · 1 assignee · Opened Sep 13, 2026
Treat missing Parquet null counts as zero for files written by parquet-rs < 53.1.0 Open

enhancement

Difficulty 4/5 3-5 days Newbie friendliness 68/100

apache/datafusion#25253 · Opened Sep 13, 2026
`SqlToRel::statement_to_plan` is superlinear for a wide `Aggregate` (exponent ≈ 1.8, DataFusion 54.1.0) Open

Difficulty 4/5 3-5 days Newbie friendliness 52/100

apache/datafusion#25248 · Opened Sep 13, 2026
Wrong results: EmitTo::First(n) collision-list compaction in GroupValuesColumn can overwrite a not-yet-visited entry's list Open

bug

apache/datafusion#25233 · 1 assignee · Opened Sep 12, 2026
`flatten` mishandles NULL values with non-empty offset ranges Open

bug

apache/datafusion#25224 · 1 assignee · Opened Sep 12, 2026
CAST statistics can produce incorrect MIN/MAX results Open

bug

apache/datafusion#25221 · 1 comment · 1 assignee · Opened Sep 12, 2026
Use exact column statistics to prove ordering through integer arithmetic Open

enhancement

apache/datafusion#25220 · 1 comment · 1 assignee · Opened Sep 12, 2026
Reuse the cached dictionary value→slot map in vectorized_equal_to instead of rebuilding it per batch Open

enhancement performance

apache/datafusion#25219 · 1 comment · 1 assignee · Opened Sep 12, 2026
CSV null_regex is applied to schema inference but never to the reader, so matching values are not null Open

Difficulty 2/5 1-3 hours Newbie friendliness 84/100

apache/datafusion#25213 · 1 comment · Opened Sep 12, 2026
Substrait: the grouping set column holds `__grouping_id`, not the set's index Open

Difficulty 3/5 1-2 days Newbie friendliness 68/100

apache/datafusion#25208 · Opened Sep 11, 2026
SortMergeJoinExec reads and sorts the whole buffered side of a partition whose streamed side is empty Open

Difficulty 4/5 3-5 days Newbie friendliness 68/100

apache/datafusion#25205 · Opened Sep 11, 2026
Ordered ARRAY_AGG accumulator retains one Arrow array per update_batch call, inflating per-row memory for grouped aggregation Open

enhancement

apache/datafusion#25199 · 1 comment · 1 assignee · Opened Sep 11, 2026
Substrait producer emits non-boolean IfThen clauses for CASE with a base expression Open

apache/datafusion#25190 · 5 comments · 1 assignee · Opened Sep 11, 2026
Clarify memory-limit guarantees for external-sort spilling Open

apache/datafusion#25183 · 2 comments · 1 assignee · Opened Sep 11, 2026
`AT TIME ZONE '+05:30'` uses the opposite sign convention from PostgreSQL Open

Difficulty 5/5 Over a week Newbie friendliness 35/100

apache/datafusion#25170 · Opened Sep 10, 2026
Document that `date_bin` with an explicit origin drifts an hour across a DST transition Open

documentation

Difficulty 2/5 1-3 hours Newbie friendliness 74/100

apache/datafusion#25168 · 1 comment · Opened Sep 10, 2026
`date_bin` and `date_trunc` disagree on timezone-aware timestamps Open

bug

Difficulty 5/5 Over a week Newbie friendliness 35/100

apache/datafusion#25167 · Opened Sep 10, 2026
TIMESTAMP WITH TIME ZONE can resolve to a timezone-naive type, and casting to it discards an existing timezone Open

bug

Difficulty 5/5 Over a week Newbie friendliness 35/100

apache/datafusion#25166 · Opened Sep 10, 2026
TPC-DS Q75 regression in DF 55 Open

bug regression

Difficulty 4/5 3-5 days Newbie friendliness 50/100

apache/datafusion#25157 · 1 comment · Opened Sep 10, 2026
`ExecutionPlan` downcast identity is broken both ways at the FFI boundary: `ForeignExecutionPlan` is opaque to host rules, and `FFI_ExecutionPlan::new`'s foreign-echo shortcut is too transparent for wrapper nodes Open

bug ffi

Difficulty 5/5 Over a week Newbie friendliness 35/100

apache/datafusion#25155 · Opened Sep 10, 2026
FFI serialization uses DefaultPhysicalProtoConverter, severing shared dynamic filter references Open

bug ffi

Difficulty 3/5 1-2 days Newbie friendliness 70/100

apache/datafusion#25154 · Opened Sep 10, 2026
FFI_PlanProperties drops scheduling_type and evaluation_type, so every plan crossing FFI misreports both Open

bug ffi

Difficulty 3/5 1-2 days Newbie friendliness 76/100

apache/datafusion#25153 · Opened Sep 10, 2026
[Umbrella] FFI planner boundary: foreign-wrapped nodes, lost plan properties, and severed dynamic filters Open

bug ffi

Difficulty 5/5 Over a week Newbie friendliness 25/100

apache/datafusion#25152 · Opened Sep 10, 2026
Reduce GitHub Actions usage (DataFusion is currently the top ASF consumer of GHA minutes) Open

development-process

Difficulty 4/5 3-5 days Newbie friendliness 45/100

apache/datafusion#25148 · 24 comments · 2 reactions · Opened Sep 10, 2026
MIN dynamic filter race across partitions Open

bug

apache/datafusion#25147 · 1 comment · 1 assignee · Opened Sep 10, 2026
Make object_store support optional for embedded DataFusion Open

Difficulty 5/5 Over a week Newbie friendliness 42/100

apache/datafusion#25145 · 4 comments · Opened Sep 10, 2026
StatisticsContext: make the pointer-keyed cache robust against node reuse when shared across a plan-rewriting pass Open

Difficulty 5/5 Over a week Newbie friendliness 38/100

apache/datafusion#25141 · Opened Sep 10, 2026
power and log simplifications return wrong results for base 1, 0 or negative Open

bug

Difficulty 3/5 1-2 days Newbie friendliness 68/100

apache/datafusion#25137 · Opened Sep 9, 2026
Lack of benchmarks for RepartionExec Open

enhancement

Difficulty 3/5 1-2 days Newbie friendliness 64/100

apache/datafusion#25127 · Opened Sep 9, 2026
[DISCUSS] Separate stable API into separate crates Open

enhancement

Difficulty 5/5 Over a week Newbie friendliness 25/100

apache/datafusion#25124 · 2 comments · Opened Sep 9, 2026
collect_list / collect_set have no GroupsAccumulator, and ArrayAggGroupsAccumulator merges per row Open

enhancement performance spark

Difficulty 5/5 Over a week Newbie friendliness 42/100

apache/datafusion#25118 · Opened Sep 9, 2026
GroupsAccumulatorAdapter: per-batch cost scales with total group count, not batch rows Open

enhancement

Difficulty 4/5 3-5 days Newbie friendliness 58/100

apache/datafusion#25116 · Opened Sep 9, 2026
Add support for SQL based registration of external catalogs Open

enhancement

Difficulty 4/5 3-5 days Newbie friendliness 48/100

apache/datafusion#25111 · Opened Sep 9, 2026
December 2026 DataFusion ASF Board Report Open

Difficulty 3/5 1-2 days Newbie friendliness 68/100

apache/datafusion#25110 · Opened Sep 9, 2026
Enable pushdown of (non-negative-cost) scalar_fn in aggregations into `TableScan` nodes Open

enhancement

Difficulty 4/5 3-5 days Newbie friendliness 48/100

apache/datafusion#25106 · 2 comments · Opened Sep 9, 2026
Substrait producer emits AGGREGATION_PHASE_UNSPECIFIED for every aggregate and window function Open

apache/datafusion#25100 · 7 comments · 1 assignee · Opened Sep 9, 2026
Make RowValues::compare's current-offset assumption self-checking Open

enhancement

apache/datafusion#25097 · 1 comment · 1 assignee · Opened Sep 9, 2026
unwrap_cast_in_comparison drops the timezone shift when unwrapping CAST(timestamp AS timestamptz) = literal Open

bug

Difficulty 3/5 1-2 days Newbie friendliness 72/100

apache/datafusion#25095 · Opened Sep 9, 2026
`PhysicalExtensionCodec` should take a `PhysicalPlanDecodeContext` instead of a `TaskContext` Open

enhancement

apache/datafusion#25089 · 2 comments · 1 assignee · Opened Sep 8, 2026

A short digest of beginner-friendly GitHub issues.