Stamatis Zampetakis created HIVE-27830:
------------------------------------------
Summary: Deprecate hive.cbo.enable property
Key: HIVE-27830
URL: https://issues.apache.org/jira/browse/HIVE-27830
Project: Hive
Issue Type: Task
Reporter: Stamatis Zampetakis
Assignee: Stamatis Zampetakis
CBO was enabled by default in Hive 1.1.0 (HIVE-8395) back in 2014. Since then
the CBO planner has matured a lot and most production environments are running
with this flag always on.
Nowadays, disabling CBO is strongly discouraged not only for performance
reasons but also because various features depend on it.
Moreover, the vast majority of testing is done using CBO on and there is not
much test coverage for the legacy code path.
It is impossible to fully support all Hive features using both CBO on/off and
keeping this flag around significantly increases maintenance cost.
The goal of this ticket is to deprecate hive.cbo.enable property and inform
users that its use is discouraged and unsupported. This would allow us to
remove this property in a subsequent release.
Ideally we should emit an informative warning message when we detect that
hive.cbo.enable is set to false.
--
This message was sent by Atlassian Jira
(v8.20.10#820010)
