Michael Ho created IMPALA-8339:
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Summary: Coordinator should be more resilient to fragment
instances startup failure
Key: IMPALA-8339
URL: https://issues.apache.org/jira/browse/IMPALA-8339
Project: IMPALA
Issue Type: Improvement
Components: Distributed Exec
Reporter: Michael Ho
Impala currently relies on statestore for cluster membership. When an Impala
executor goes offline, it may take a while for statestore to declare that node
as unavailable and for that information to be propagated to all coordinator
nodes. Within this window, some coordinator nodes may still attempt to issue
RPCs to the faulty node, resulting in RPC failures which resulted in query
failures. In other words, many queries may fail to start within this window
until all coordinator nodes get the latest information on cluster membership.
Going forward, coordinator may need to fall back to using backup executors for
each fragments in case some of the executors are not available. Moreover,
*coordinator should treat the cluster membership information from statestore
(or any external source of truth e.g. etcd) as hints instead of ground truth*
and adjust the scheduling of fragment instances based on the availability of
the executors from the coordinator's perspective.
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