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https://issues.apache.org/jira/browse/FLINK-26793?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=17516904#comment-17516904
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Etienne Chauchot commented on FLINK-26793:
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[~bumblebee] in particular do you see in Flink logs the message you referred
from stackoverflow: "{_}query is not prepared on /XX.YY.91.205:9042, preparing
before retrying executing. Seeing this message a few times is fine, but seeing
it a lot may be source of performance problems"{_} in addition to the scylla
message you referred in the ticket.
Also, please go to Flink monitoring UI in the _Checkpoints/Overview_ tab and
search for _Latest Restore._ That way we can check if there was a checkpoint
restore and validate/invalidate my supposition about restoring entailing a
re-creation of the MappingManager (in case it is not part of the Sink Operator
snapshot state).
Also please confirm that in the code you showed above _datastream_ object
contains POJOs and not tuples so that we make sure the pipeline indeed uses
_CassandraPojoSink_ (sink instanciation is automatic depending on the content
of your DataStream)
> Flink Cassandra connector performance issue
> --------------------------------------------
>
> Key: FLINK-26793
> URL: https://issues.apache.org/jira/browse/FLINK-26793
> Project: Flink
> Issue Type: Improvement
> Components: Connectors / Cassandra
> Affects Versions: 1.14.4
> Reporter: Jay Ghiya
> Assignee: Etienne Chauchot
> Priority: Major
>
> A warning is observed during long runs of flink job stating “Insertions into
> scylla might be suffering. Expect performance problems unless this is
> resolved.”
> Upon initial analysis - “flink cassandra connector is not keeping instance of
> mapping manager that is used to convert a pojo to cassandra row. Ideally the
> mapping manager should have the same life time as cluster and session objects
> which are also created once when the driver is initialized”
> Reference:
> https://stackoverflow.com/questions/59203418/cassandra-java-driver-warning
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