We have different applications/scripts that are fetching data via Impala.
These are jdbc connections. The output of the queries ends up with exceptions
Caused by: com.cloudera.support.exceptions.GeneralException: [Simba][ImpalaJDBCDriver](500051) ERROR processing query/statement. Error Code: null, SQL state: HY000,
The issue gets resolved after a service restart of Impala.
Is there a way to check how many open connections ? Please let us know.
Thanks and regards
You might also create triggers in CM by going to CM > Impala > Charts on the right hand side > Queries Across Impala Daemons
And then follow on screen instructions.
More details here:
If you are looking for number of sessions against HS2 in impala you can use the chart library that you can found in CM -> IMPALA -> Chart library - >
You should look at fe_service_threads, what is your current setting and consider increasing it if needed. When you are seeing exception/timeout on connection have a look at dashboard using following ts_query
'select thrift_server_hiveserver2_frontend_connections_in_use' if this value is approaching the default setting of fe_service_threads then you know your running out of connections. The default setting can be viewed in the service page/varz.