Dayue Gao created KYLIN-2079:
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Summary: add explicit configuration knob for coprocessor timeout
Key: KYLIN-2079
URL: https://issues.apache.org/jira/browse/KYLIN-2079
Project: Kylin
Issue Type: Sub-task
Components: Storage - HBase
Affects Versions: v1.5.4.1
Reporter: Dayue Gao
Assignee: Dayue Gao
Fix For: v1.6.0
Current self-termination timeout for CubeVisitService is calculated as the
product of three parameters:
* hbase.rpc.timeout
* hbase.client.retries.number (hardcode to 5)
* kylin.query.cube.visit.timeout.times
It has a few problems:
# due to this timeout being longer than hbase.rpc.timeout, user sees "Error in
coprocessor" instead of more descriptive GTScanSelfTerminatedException.
moreover, the request (probably a bad query) will be retried 5 times,
increasing pressure on regionserver
# it's not intuitive to set coprocessor timeout by adjusting
kylin.query.cube.visit.timeout.times
I propose the following changes:
# add a new kylin configuration "kylin.query.coprocessor.timeout.seconds" to
explicitly set coprocessor timeout. It defaults to 0, which means no value, use
hbase.rpc.timeout x 0.9 instead. When user sets it to a positive number, kylin
will use min(hbase.rpc.timeout x 0.9, kylin.query.coprocessor.timeout.seconds)
as coprocessor timeout
# remove "kylin.query.cube.visit.timeout.times". For cube visit timeout
(ExpectedSizeIterator), it's really a last resort, in case coprocessor didn't
terminate itself. I don't see too much needs for user to control it, set it to
coprocessor timeout x 10 should be a large enough.
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