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The TableFlattener takes a nested dataset and creates an equivalent unnested dataset. The unnested dataset is saved as Parquet. When an array or map is encountered in the original table, the flattener creates a new table and adds an id column to it which references the row in the parent table. Joining on the id column should produce the original dataset. The flattened dataset should be loaded into Postgres in order to run the query generator (in nested types mode) on it. There is a script that automates generaration, flattening and loading random data into Postgres and Impala: testdata/bin/generate-load-nested.sh -f Testing: - ran ./testdata/bin/generate-load-nested.sh -f and random nested data was generated and flattened as expected. Change-Id: I7e7a8e53ada9274759a3e2128b97bec292c129c6 Reviewed-on: http://gerrit.cloudera.org:8080/5787 Reviewed-by: Alex Behm <alex.behm@cloudera.com> Tested-by: Impala Public Jenkins
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 and Amazon S3.
- Wide analytic SQL support, including window functions and subqueries.
- On-the-fly code generation using LLVM to generate CPU-efficient code tailored specifically to each individual query.
- Support for the most commonly-used Hadoop file formats, including the Apache Parquet (incubating) project.
- Apache-licensed, 100% open source.
More about Impala
To learn more about Impala as a business user, or to try Impala live or in a VM, please visit the Impala homepage.
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.
Build Instructions
See bin/bootstrap_build.sh.
Export Control Notice
This distribution uses cryptographic software and may be subject to export controls. Please refer to EXPORT_CONTROL.md for more information.