Impala connections to the backend client are subject to failure
in cases when the network is momentarily overloaded.
To avoid failed queries due to transient network problems, you can
configure the number of Thrift connection retries using the following
option:
-
Log in to the CDP web interface and navigate to the Data Warehouse service.
-
In the Data Warehouse service, click Virtual Warehouses in
the left navigation panel.
-
Select the Impala Virtual Warehouse, click options
for the warehouse you want to
set the timeout and retry options.
-
Click Edit and navigate to Impala Coordinatorunder Configurationstab.
-
Using the + sign, specify the following if the options are not already added.
To avoid failed queries due to transient network problems, you can
configure the number of Thrift connection retries using the
following option:
- The
--backend_client_connection_num_retries
option specifies the number of times Impala will try connecting to
the backend client after the first connection attempt fails. By
default, impalad will attempt three
re-connections before it returns a failure.
You can configure timeouts for sending and receiving data from the
backend client. Therefore, if for some reason a query does not respond, instead
of waiting indefinitely for a response, Impala will terminate the
connection after a configurable timeout.
- The
--backend_client_rpc_timeout_ms option can
be used to specify the number of milliseconds Impala should wait
for a response from the backend client before it terminates the
connection and signals a failure. The default value for this
property is 300000 milliseconds, or 5 minutes.
- Click Apply and restart
Impala.
