[jira] [Commented] (IMPALA-9124) Transparently retry queries that fail due to cluster membership changes

["ASF subversion and git services (Jira)" <ji...@apache.org>]

    [ https://issues.apache.org/jira/browse/IMPALA-9124?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16992006#comment-16992006 ] 

ASF subversion and git services commented on IMPALA-9124:
---------------------------------------------------------

Commit 85425b81f04c856d7d5ec375242303f78ec7964e in impala's branch refs/heads/master from Sahil Takiar
[ https://gitbox.apache.org/repos/asf?p=impala.git;h=85425b8 ]

IMPALA-9124: ImpalaServer and ClientRequestState refactoring

Re-factoring several areas of the ImpalaServer and ClientRequestState
in preparation for future work required for transparent query retries.

Re-factored TExecRequest ownership in ClientRequestState. Previously,
the TExecRequest was passed to the ClientRequestState via the
Exec(TExecRequest) method. Now it is created and owned by the
ClientRequestState and only exposed as a constant reference. It is
stored as a plain member variable.

Re-factored ImpalaServer::UnregisterQuery into multiple methods. Made
ClientRequestStateMap a dedicated class that extends ShardedQueryMap
with additional methods to add and delete a ClientRequestState. The
re-factoring breaks up the large UnregisterQuery method into multiple
smaller method and adds some additional code documentation.

Re-factored ImpalaServer::client_request_state_map_ into a separate
class.

Testing:
* Ran core tests

Change-Id: Ib92c932a69802225af3fd9bf15f85c85317acaca
Reviewed-on: http://gerrit.cloudera.org:8080/14755
Reviewed-by: Sahil Takiar <st...@cloudera.com>
Tested-by: Impala Public Jenkins <im...@cloudera.com>


> Transparently retry queries that fail due to cluster membership changes
> -----------------------------------------------------------------------
>
>                 Key: IMPALA-9124
>                 URL: https://issues.apache.org/jira/browse/IMPALA-9124
>             Project: IMPALA
>          Issue Type: New Feature
>          Components: Backend, Clients
>            Reporter: Sahil Takiar
>            Assignee: Sahil Takiar
>            Priority: Critical
>         Attachments: Impala Transparent Query Retries.pdf
>
>
> Currently, if the Impala Coordinator or any Executors run into errors during query execution, Impala will fail the entire query. It would improve user experience to transparently retry the query for some transient, recoverable errors.
> This JIRA focuses on retrying queries that would otherwise fail due to cluster membership changes. Specifically, node failures that cause changes in the cluster membership (currently the Coordinator cancels all queries running on a node if it detects that the node is no longer part of the cluster) and node blacklisting (the Coordinator blacklists a node because it detects a problem with that node - can’t execute RPCs against the node). It is not focused on retrying general errors (e.g. any frontend errors, MemLimitExceeded exceptions, etc.).



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