kangkaisen created KYLIN-1695:
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Summary: disable cardinality calculation job when loading hive
table
Key: KYLIN-1695
URL: https://issues.apache.org/jira/browse/KYLIN-1695
Project: Kylin
Issue Type: Bug
Components: Job Engine
Affects Versions: v1.5.1
Reporter: kangkaisen
Assignee: Dong Li
When user loads/reloads hive tables from web console, kylin will submit a mr
job asynchronously to calculate column cardinalities. This has four major
problems:
# the calculated cardinality is stored in table metadata, but never used in
cubing/querying
# table may change after loading, so the cardinality doesn't necessarily
reflect the actual value
# the current `HiveColumnCardinalityJob` has many limitations, e.g., it doesn't
support views
# the `HiveColumnCardinalityJob` may use lots of resources when computing
cardinality of partitioned table
Due to these problems, we should disable it by default and (maybe) remove it in
future releases.
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