IMPALA-12925: Fix decimal data type for external JDBC table

Decimal type is a primitive data type for Impala. Current code returns
wrong values for columns with decimal data type in external JDBC tables.

This patch fixes wrong values returned from JDBC data source, and
supports pushing down decimal type of predicates to remote database
and remote Impala.
The decimal precision and scale of the columns in external JDBC table
must be no less than the decimal precision and scale of the
corresponding columns in the table of remote database. Otherwise,
Impala fails with an error since it may cause truncation of decimal
data.

Testing:
 - Added Planner test for pushing down decimal type of predicates.
 - Added end-to-end unit-tests for tables with decimal type of columns
   for Postgres, MySQL, and Impala-to-Impala.
 - Passed core-tests.

Change-Id: I8c9d2e0667c42c0e52436b158e3dfe3ec14b9e3b
Reviewed-on: http://gerrit.cloudera.org:8080/21218
Reviewed-by: Michael Smith <michael.smith@cloudera.com>
Reviewed-by: Abhishek Rawat <arawat@cloudera.com>
Tested-by: Impala Public Jenkins <impala-public-jenkins@cloudera.com>
14 files changed
tree: b07353711947927d09389d0b87ae467f7a986e4c
  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 open data and table formats.

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:

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.