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https://issues.apache.org/jira/browse/IMPALA-8712?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16873765#comment-16873765
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Michael Ho edited comment on IMPALA-8712 at 6/28/19 7:22 AM:
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On the other hand, {{exec_rpc_thread_pool_}} allows serialization of the RPC
parameters to happen in parallel so it may not strictly be a simple conversion
to asynchronous RPC without regression. So careful evaluation with huge RPC
parameters (e.g. a large number of scan ranges) may be needed to see if there
may be regression as a result.
Some of the serialization overhead with ExecQueryFInstance() RPC even after
IMPALA-7467 is still Thrift related as we just serialize a bunch of Thrift
structures into a binary blob and send them via KRPC sidecar. The serialization
is done in parallel by threads in {{exec_rpc_thread_pool_}}. -If we convert
those Thrift structures into Protobuf, then the serialization can be done in
parallel by reactor threads in the KRPC stack.-
was (Author: kwho):
On the other hand, {{exec_rpc_thread_pool_}} allows serialization of the RPC
parameters to happen in parallel so it may not strictly be a simple conversion
to asynchronous RPC without regression. So careful evaluation with huge RPC
parameters (e.g. a large number of scan ranges) may be needed to see if there
may be regression as a result.
Some of the serialization overhead with ExecQueryFInstance() RPC even after
IMPALA-7467 is still Thrift related as we just serialize a bunch of Thrift
structures into a binary blob and send them via KRPC sidecar. The serialization
is done in parallel by threads in {{exec_rpc_thread_pool_}}. If we convert
those Thrift structures into Protobuf, then the serialization can be done in
parallel by reactor threads in the KRPC stack.
> Convert ExecQueryFInstance() RPC to become asynchronous
> -------------------------------------------------------
>
> Key: IMPALA-8712
> URL: https://issues.apache.org/jira/browse/IMPALA-8712
> Project: IMPALA
> Issue Type: Sub-task
> Components: Distributed Exec
> Affects Versions: Impala 3.3.0
> Reporter: Michael Ho
> Assignee: Thomas Tauber-Marshall
> Priority: Major
>
> Now that IMPALA-7467 is fixed, ExecQueryFInstance() can utilize the async RPC
> capabilities of KRPC instead of relying on the half-baked way of using
> {{ExecEnv::exec_rpc_thread_pool_}} to start query fragment instances. We
> already have a reactor thread pool in KRPC to handle sending client RPCs
> asynchronously. Also various tasks under IMPALA-5486 can also benefit from
> making ExecQueryFInstance() asynchronous so the RPCs can be cancelled.
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