Apache DataFusion SQL Query Engine
C-Rank Grade: A (Welcoming) - 63/100
External PR Merge Rate: 63%
Response Time: 20h
First Timer Success: 57%
apache/datafusion has a recorded first-timer success rate of 56.6%. Repositories ranked A typically provide actionable feedback during code reviews and actively nurture new community contributors.
Maintainers in apache/datafusion respond to incoming external pull requests in approximately 20.2 hours on average. Keeping PRs focused on single tasks and ensuring tests pass helps maintainers review faster.
The C-Rank™ system evaluates GitHub projects on a 0–100 scale using real data: PR merge rates, review turnaround time, active maintainer presence, and first-time contributor success. A score of 63.3 places apache/datafusion in the A tier.
The external contributor pull request merge rate for apache/datafusion is 62.6%, based on public PR activity from non-core contributors.
apache/datafusion currently has 16 active issue(s) tagged with beginner-friendly labels like "good first issue", "beginner", or "up-for-grabs".
Highly welcoming maintainers in apache/datafusion. Prompt code reviews with positive guidance for new contributors.
Average Response Latency
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External Acceptance Rate
Percentage of community pull requests successfully merged into main.
First PR Conversion
Rate at which developers submitting their first repository PR succeed.
Show contributors that your repository actively reviews and merges external pull requests.
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Historical health & responsiveness evolution
External PR acceptance
First PR success rate
50% receive response in
90% receive response in
Maintainer review activity heatmap & prime window prediction
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Maintainers are most responsive around 18:00 UTC (18:00 UTC in your timezone). Recommended submission window is Monday - Wednesday from 16:00 to 20:00 UTC (16:00 - 20:00 UTC local).
Limited recent maintainer review activity recorded for this repository. Prediction based on heuristic baseline.
Maintainer Strategy: Maintainer Sweet Spot: PRs under 150 lines merge in ~13 hours (78% approval). Large PRs (>500 lines) take ~97 hours (28% approval). Keep your diff compact for rapid review.
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context apache/arrow-rs#3199 apache/arrow-rs#10902 once apache/arrow-rs#10902 (arrow-rs v60.0.0) is merged update call sites in DataFusion to use the new equal_datatypes instead of custom logic. know callsites #4347 #4233
Describe the bug When a query renames a column using a DataFusion reserved name, it currently fails with an error message that does not clearly tell the user how to resolve the issue. For example: Arrow error: Invalid argument error: Invalid comparison operation: Float64 > Boolean Even though the user's query doesn't contain a Float64 > Boolean comparison, the error message is misleading. It would be good to improve the error message so that it clearly tells the user to choose a different column name instead of using a DF reserved name. To Reproduce ❯ datafusion-cli DataFusion CLI v55.0.0 > CREATE TABLE readings(range_idx INT) AS VALUES (1); 0 row(s) fetched. Elapsed 0.039 seconds. -- ❌ bug reproducer, `__common_expr_2` is a DF reserved column name > SELECT CASE WHEN (range_idx = 1) THEN normalized_value ELSE 0.0 END AS result FROM ( SELECT range_idx, CASE WHEN (range_idx = 1) THEN capped_value ELSE 0.0 END AS normalized_value FROM ( SELECT range_idx,
Is your feature request related to a problem or challenge? The API health policy deprecation guidelines say deprecated APIs remain for 6 major versions or 6 months, whichever is longer main is at 55.0.0, so the next release is 56.0.0 and anything deprecated in 50.0.0 or earlier can now be removed. These eight are independent one-offs, each a few lines in a different crate: Item Deprecated in Replacement ScalarValue::raw_data 46.0.0 to_array get_statistics_with_limit 47.0.0 get_files_with_limit and compute_all_files_statistics DisplayableExecutionPlan::to_stringified 47.0.0 indent or tree_render ExprSimplifier::simplify_with_cycle_count 48.0.0 simplify_with_cycle_count_transformed DynEq / DynHash re-export 50.0.0 datafusion_expr_common::dyn_eq ExecutionProps::start_execution 50.0.0 mark_start_execution UserDefinedFunctionPlanner 50.0.0 UnicodeFunctionPlanner and DateTimeFunctionPlanner Now::new 50.2.0 new_with_config Describe the solution you'd like Remove all
Is your feature request related to a problem or challenge? The API health policy deprecation guidelines say deprecated APIs remain for 6 major versions or 6 months, whichever is longer main is at 55.0.0, so the next release is 56.0.0 and anything deprecated in 50.0.0 or earlier can now be removed. Four such items remain in the datafusion-datasource-parquet crate: Item Deprecated in Replacement fetch_parquet_metadata 50.0.0 DFParquetMetadata::fetch_metadata fetch_statistics 50.0.0 DFParquetMetadata::fetch_statistics statistics_from_parquet_meta_calc 50.0.0 DFParquetMetadata::statistics_from_parquet_metadata ParquetSource::predicate 50.2.0 ParquetSource::filter Describe the solution you'd like Remove all four items and supporting code While this is a breaking Rust API change, the PR should carry the api change label DO NOT add a note to the 56.0.0 upgrade guide, as removing deprecated APIs is clear and the compiler has guided people off them in the past Describe alter
Is your feature request related to a problem or challenge? The API health policy deprecation guidelines say deprecated APIs remain for 6 major versions or 6 months, whichever is longer main is at 55.0.0, so the next release is 56.0.0 and anything deprecated in 50.0.0 or earlier can now be removed. Four such methods remain in datafusion/expr/src/udf.rs: Item Deprecated in Replacement ScalarUDFImpl::is_nullable 45.0.0 return_field_from_args ScalarUDF::display_name 50.0.0 none, method is unused ScalarUDF::is_nullable 50.0.0 return_field_from_args ScalarUDFImpl::display_name 50.0.0 none, method is unused Describe the solution you'd like Remove all four methods and supporting code While this is a breaking Rust API change, the PR should carry the api change label DO NOT add a note to the 56.0.0 [upgrade guide], as removing deprecated APIs is clear and the compiler has guided people off them in the past Describe alternatives you've considered N/A Additional context Follow
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When evaluating whether to contribute to apache/datafusion, response velocity and maintainer engagement are crucial. GetMerged continuously tracks pull request trajectories, first-comment latency, and code review rounds to help developers avoid submitting pull requests to backlogged repositories.
Currently, maintainers of apache/datafusion acknowledge new external contributions in approximately 20 hours. Out of all submitted pull requests from non-core authors in the last 180-day window, 62.6% were successfully merged into the primary branch.
apache/datafusion has a recorded first-timer success rate of 56.6%. Repositories ranked Welcoming typically provide actionable feedback during code reviews and actively nurture new community contributors.
The initial maintainer response time averages ~20 hours. Keeping PRs scoped to single concerns and ensuring CI checks succeed will optimize review turnaround.
The C-Rank™ index scores repositories on a 0 to 100 scale using an objective formula: external PR merge rates, initial response speed, active maintainer count, and first-time contributor retention. A score of 63.3 places apache/datafusion in the Welcoming tier.
The external pull request merge rate is 62.6%. GetMerged isolates non-core community contributions so external developers get an accurate benchmark of PR acceptance probability.
Yes, apache/datafusion currently has 16 active issue(s) tagged with beginner-friendly labels. You can inspect these directly from the repository issues tab.
All metrics displayed for apache/datafusion are automatically retrieved via the public GitHub API and recalculated daily. Insider pull requests submitted by repository owners or organization members are excluded from merge rate calculations to preserve objective external contributor statistics.