mirror of
https://github.com/apache/impala.git
synced 2026-01-02 12:00:33 -05:00
54a46e9459
The bug: Evaluating !empty() predicates at non-scan nodes interacts poorly with our BE projection of collection slots. For example, rows could incorrectly be filtered if a !empty() predicate is assigned to a plan node that comes after the unnest of the collection that also performs the projection. The fix: This patch reworks the generation of !empty() predicates introduced in IMPALA-2663 for correctness purposes. The predicates are generated in cases where we can ensure that they will be assigned only by the parent scan, and no other plan node. The conditions are as follows: - collection table ref is relative and non-correlated - collection table ref represents the rhs of an inner/cross/semi join - collection table ref's parent tuple is not outer joined Change-Id: Ie975ce139a103285c4e9f93c59ce1f1d2aa71767 Reviewed-on: http://gerrit.cloudera.org:8080/2399 Reviewed-by: Alex Behm <alex.behm@cloudera.com> Reviewed-by: Silvius Rus <srus@cloudera.com> Tested-by: Internal 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.