14.4. Configuring the Netty transport

If this is true then Java non-blocking NIO will be used. If set to false the older, blocking Java IO will be used. If handling many concurrent connections to the server is a requirement, the non-blocking Java NIO method is highly recommended. Java NIO does not maintain a thread per connection so can scale to many more concurrent connections than the older blocking IO method. If handling many concurrent connections is not required, slightly better performance might be gained by using older blocking IO method. The default value for this property is false on the server side and false on the client side.

The host name or IP address to connect to (for connectors) or listen on (for acceptors). The default value is localhost.

Acceptors can be configured with multiple comma-delimited hosts or IP addresses. Multiple addresses are not valid for connectors. 0.0.0.0 specifies that all network interfaces of a host should be accepted.

Specifies the port to connect to (for connectors) or listen on (for acceptors). The default value is 5445.

If true, Nagle's algorithm is enabled. The default value is true.

Defines the size of the TCP send buffer in bytes. The default value is 32768 (32 kilobytes). TCP buffer size should be tuned according to the bandwidth and latency of your network. The buffer size in bytes should be equal to the bandwidth in bytes-per-second multiplied by the network round-trip-time (RTT) in seconds. RTT can be measured using the ping utility. For fast networks, you may wish to increase the buffer size from the default value.

Defines the size of the TCP receive buffer in bytes. The default value is 32768 (32 kilobytes).

HornetQ can be configured to place write operations into batches for up to batch-delay milliseconds. This can increase overall throughput for very small messages, but does so at the expense of an increase in average latency for message transfer. The default value is 0 milliseconds.

When a message arrives on the server and is delivered to consumers, by default the delivery occurs on a different thread to that in which the message arrived. This gives the best overall throughput and scalability, especially on multi-core machines. However, it also introduces additional latency due to the context switch required. For the lowest latency (and possible reduction of throughput), set direct-deliver to true (the default). For highest throughput, set to false.

When configured to use NIO, by default HornetQ uses three times the number of threads as cores (or hyper-threads) reported by Runtime.getRuntime().availableProcessors() to process incoming packets. nio-remoting-threads overrides this and defines the number of threads to use. The default is -1, which represents three times the value from Runtime.getRuntime().availableProcessors().