rok commented on code in PR #13873: URL: https://github.com/apache/arrow/pull/13873#discussion_r949530023
########## docs/source/cpp/flight.rst: ########## @@ -172,6 +172,110 @@ request/response. On the server, they can inspect incoming headers and fail the request; hence, they can be used to implement custom authentication methods. +.. _flight-best-practices: + +Best practices +============== + +gRPC +---- + +When using default gRPC transport options can be passed to it via +:member:`arrow::flight::FlightClientOptions::generic_options`. For example: + +.. code-block:: cpp + + auto options = FlightClientOptions::Defaults(); + // Set a very low limit at the gRPC layer to fail all calls + options.generic_options.emplace_back(GRPC_ARG_MAX_RECEIVE_MESSAGE_LENGTH, 4); + +Also see `best gRPC practices`_ and available `gRPC keys`_. + + +Re-use clients whenever possible +-------------------------------- + +Closing clients causes gRPC to close and clean up connections which can take +several seconds per connection. This will stall server and client threads if +done too frequently. Client reuse will avoid this issue. + +Don’t round-robin load balance +------------------------------ + +Round robin balancing can cause every client to have an open connection to +every server causing an unexpected number of open connections and a depletion +of resources. + +Debugging +--------- + +Use netstat to see the number of open connections. +For debug - env GRPC_VERBOSITY=info GRPC_TRACE=http will print the initial +headers (on both sides) so you can see if grpc established the connection or +not. It will also print when a message is sent, so you can tell if the +connection is open or not. +Note: "connect" isn't really a connect and we’ve observed that gRPC does not +give you the actual error until you first try to make a call. This can cause +error being reported at unexpected times. + +Use ListFlights sparingly Review Comment: Removed from here and from Go doc. ########## docs/source/cpp/flight.rst: ########## @@ -172,6 +172,110 @@ request/response. On the server, they can inspect incoming headers and fail the request; hence, they can be used to implement custom authentication methods. +.. _flight-best-practices: + +Best practices +============== + +gRPC +---- + +When using default gRPC transport options can be passed to it via +:member:`arrow::flight::FlightClientOptions::generic_options`. For example: + +.. code-block:: cpp + + auto options = FlightClientOptions::Defaults(); + // Set a very low limit at the gRPC layer to fail all calls + options.generic_options.emplace_back(GRPC_ARG_MAX_RECEIVE_MESSAGE_LENGTH, 4); + +Also see `best gRPC practices`_ and available `gRPC keys`_. + + +Re-use clients whenever possible +-------------------------------- + +Closing clients causes gRPC to close and clean up connections which can take +several seconds per connection. This will stall server and client threads if +done too frequently. Client reuse will avoid this issue. + +Don’t round-robin load balance +------------------------------ + +Round robin balancing can cause every client to have an open connection to Review Comment: Added. -- This is an automated message from the Apache Git Service. To respond to the message, please log on to GitHub and use the URL above to go to the specific comment. To unsubscribe, e-mail: [email protected] For queries about this service, please contact Infrastructure at: [email protected]
