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# Apache DataFusion Comet

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<img src="docs/source/_static/images/DataFusionComet-Logo-Light.png" width="512" alt="logo"/>

Apache DataFusion Comet is a high-performance accelerator for Apache Spark, built on top of the powerful
[Apache DataFusion] query engine. Comet is designed to significantly enhance the
performance of Apache Spark workloads while leveraging commodity hardware and seamlessly integrating with the
Spark ecosystem without requiring any code changes.

Comet also accelerates Apache Iceberg, when performing Parquet scans from Spark.

[Apache DataFusion]: https://datafusion.apache.org

# Benefits of Using Comet

## Run Spark Queries at DataFusion Speeds

Comet delivers a performance speedup for many queries, enabling faster data processing and shorter time-to-insights.

The following chart shows the time it takes to run the 22 TPC-H queries against 100 GB of data in Parquet format
using a single executor with 8 cores. See the [Comet Benchmarking Guide](https://datafusion.apache.org/comet/contributor-guide/benchmarking.html)
for details of the environment used for these benchmarks.

When using Comet, the overall run time is reduced from 687 seconds to 302 seconds, a 2.2x speedup.

![](docs/source/_static/images/benchmark-results/0.11.0/tpch_allqueries.png)

Here is a breakdown showing relative performance of Spark and Comet for each TPC-H query.

![](docs/source/_static/images/benchmark-results/0.11.0/tpch_queries_compare.png)

The following charts shows how much Comet currently accelerates each query from the benchmark.

### Relative speedup

![](docs/source/_static/images/benchmark-results/0.11.0/tpch_queries_speedup_rel.png)

### Absolute speedup

![](docs/source/_static/images/benchmark-results/0.11.0/tpch_queries_speedup_abs.png)

These benchmarks can be reproduced in any environment using the documentation in the
[Comet Benchmarking Guide](https://datafusion.apache.org/comet/contributor-guide/benchmarking.html). We encourage
you to run your own benchmarks.

Results for our benchmark derived from TPC-DS are available in the [benchmarking guide](https://datafusion.apache.org/comet/contributor-guide/benchmark-results/tpc-ds.html).

## Use Commodity Hardware

Comet leverages commodity hardware, eliminating the need for costly hardware upgrades or
specialized hardware accelerators, such as GPUs or FPGA. By maximizing the utilization of commodity hardware, Comet
ensures cost-effectiveness and scalability for your Spark deployments.

## Spark Compatibility

Comet aims for 100% compatibility with all supported versions of Apache Spark, allowing you to integrate Comet into
your existing Spark deployments and workflows seamlessly. With no code changes required, you can immediately harness
the benefits of Comet's acceleration capabilities without disrupting your Spark applications.

## Tight Integration with Apache DataFusion

Comet tightly integrates with the core Apache DataFusion project, leveraging its powerful execution engine. With
seamless interoperability between Comet and DataFusion, you can achieve optimal performance and efficiency in your
Spark workloads.

## Active Community

Comet boasts a vibrant and active community of developers, contributors, and users dedicated to advancing the
capabilities of Apache DataFusion and accelerating the performance of Apache Spark.

## Getting Started

To get started with Apache DataFusion Comet, follow the
[installation instructions](https://datafusion.apache.org/comet/user-guide/installation.html). Join the
[DataFusion Slack and Discord channels](https://datafusion.apache.org/contributor-guide/communication.html) to connect
with other users, ask questions, and share your experiences with Comet.

Follow [Apache DataFusion Comet Overview](https://datafusion.apache.org/comet/about/index.html#comet-overview) to get more detailed information

## Contributing

We welcome contributions from the community to help improve and enhance Apache DataFusion Comet. Whether it's fixing
bugs, adding new features, writing documentation, or optimizing performance, your contributions are invaluable in
shaping the future of Comet. Check out our
[contributor guide](https://datafusion.apache.org/comet/contributor-guide/contributing.html) to get started.

## License

Apache DataFusion Comet is licensed under the Apache License 2.0. See the [LICENSE.txt](LICENSE.txt) file for details.

## Acknowledgments

We would like to express our gratitude to the Apache DataFusion community for their support and contributions to
Comet. Together, we're building a faster, more efficient future for big data processing with Apache Spark.
