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apache / impala / 0616a8f831d63b3c77d80198ff24b64f07b3b849
commit0616a8f831d63b3c77d80198ff24b64f07b3b849[log] [tgz]
authorRiza Suminto <riza.suminto@cloudera.com>Wed Nov 08 12:24:14 2023 -0800
committerRiza Suminto <riza.suminto@cloudera.com>Thu Nov 09 19:47:24 2023 +0000
tree25ed201875635e507033673e6456773ba0a84138
parent3e99dfcd169fe380356eeb74064372fc38201cdc [diff]
IMPALA-12548: Fix behavior of AGG_MEM_CORRELATION_FACTOR

AGG_MEM_CORRELATION_FACTOR has a valid value between 0.0 to 1.0. Like
JOIN_SELECTIVITY_CORRELATION_FACTOR option, the correlation factor here
is meant to reflect the correlation coefficient between grouping
columns. A high value of AGG_MEM_CORRELATION_FACTOR should mean a high
correlation between grouping columns.

However, the implementation of this query option behaves the opposite.
1.0 is interpreted as no correlation at all in the code, while <1.0 is
interpreted as somewhat correlated.

This patch fixes the behavior so that the planner lower memory estimate
as AGG_MEM_CORRELATION_FACTOR go higher.

Testing:
- Fix and pass PlannerTest#testAggNodeMaxMemEstimate.
- Add testAggNodeLowMemEstimate and testAggNodeHighMemEstimate.

Change-Id: I6f81db32a1818abc257957f6de942b5c9f36211a
Reviewed-on: http://gerrit.cloudera.org:8080/20684
Reviewed-by: Michael Smith <michael.smith@cloudera.com>
Reviewed-by: Kurt Deschler <kdeschle@cloudera.com>
Tested-by: Impala Public Jenkins <impala-public-jenkins@cloudera.com>
5 files changed
tree: 25ed201875635e507033673e6456773ba0a84138
  1. .devcontainer/
  2. be/
  3. bin/
  4. cmake_modules/
  5. common/
  6. docker/
  7. docs/
  8. fe/
  9. infra/
  10. java/
  11. lib/
  12. package/
  13. security/
  14. shell/
  15. ssh_keys/
  16. testdata/
  17. tests/
  18. www/
  19. .clang-format
  20. .clang-tidy
  21. .gitattributes
  22. .gitignore
  23. buildall.sh
  24. CMakeLists.txt
  25. EXPORT_CONTROL.md
  26. LICENSE.txt
  27. LOGS.md
  28. NOTICE.txt
  29. README-build.md
  30. README.md
  31. setup.cfg
README.md

Welcome to Impala

Lightning-fast, distributed SQL queries for petabytes of data stored in Apache Hadoop clusters.

Impala is a modern, massively-distributed, massively-parallel, C++ query engine that lets you analyze, transform and combine data from a variety of data sources:

  • Best of breed performance and scalability.
  • Support for data stored in HDFS, Apache HBase, Apache Kudu, Amazon S3, Azure Data Lake Storage, Apache Hadoop Ozone and more!
  • Wide analytic SQL support, including window functions and subqueries.
  • On-the-fly code generation using LLVM to generate lightning-fast code tailored specifically to each individual query.
  • Support for the most commonly-used Hadoop file formats, including Apache Parquet and Apache ORC.
  • Support for industry-standard security protocols, including Kerberos, LDAP and TLS.
  • Apache-licensed, 100% open source.

More about Impala

The fastest way to try out Impala is a quickstart Docker container. You can try out running queries and processing data sets in Impala on a single machine without installing dependencies. It can automatically load test data sets into Apache Kudu and Apache Parquet formats and you can start playing around with Apache Impala SQL within minutes.

To learn more about Impala as a user or administrator, or to try Impala, please visit the Impala homepage. Detailed documentation for administrators and users is available at Apache Impala documentation.

If you are interested in contributing to Impala as a developer, or learning more about Impala's internals and architecture, visit the Impala wiki.

Supported Platforms

Impala only supports Linux at the moment. Impala supports x86_64 and has experimental support for arm64 (as of Impala 4.0). Impala Requirements contains more detailed information on the minimum CPU requirements.

Supported OS Distributions

Impala runs on Linux systems only. The supported distros are

  • Ubuntu 16.04/18.04
  • CentOS/RHEL 7/8

Other systems, e.g. SLES12, may also be supported but are not tested by the community.

Export Control Notice

This distribution uses cryptographic software and may be subject to export controls. Please refer to EXPORT_CONTROL.md for more information.

Build Instructions

See Impala's developer documentation to get started.

Detailed build notes has some detailed information on the project layout and build.