Naveen Gangam created HIVE-21718:
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Summary: Improvement performance of UpdateInputAccessTimeHook
Key: HIVE-21718
URL: https://issues.apache.org/jira/browse/HIVE-21718
Project: Hive
Issue Type: Improvement
Components: HiveServer2
Affects Versions: 2.1.1
Reporter: Naveen Gangam
Assignee: Naveen Gangam
Currently, Hive does not update the lastAccessTime property for any entities
when a query accesses them. Thus it has not possible to know when a table was
last accessed.
Hive does provide a configurable hook to HS2 that is execcuted as a pre-query
hook prior to the query being executed. However, this hook is inefficient
because for each table or partition it is attempting to update time for, it
executes an "alter table ... " command internally. This is bad
1) For a query touching 1000's of partitions, this hook takes forever to update
them.
2) Meanwhile, it is holding up the original query from executing.
So even though we do not recommend using the hook, because the reward is too
little (having lastAccessTime updated), we realize there is no other means to
achieve this.
Also, we can improve the performance of the hook significantly by adding a new
thrift API on HMS to update the lastAccessTime on the database rows directly
instead of going to HMS front end for 1 entity at time (leading to 1000's of
HMS calls that lead to multiple 1000's of calls to the database).
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