Setting Batch Size

The AMPS clients include a batch size parameter that specifies how many messages the AMPS server will return to the client in a single batch when returning the results of a SOW query. The 60East clients set a batch size of 10 by default. This batch size works well for common message sizes and network configurations.

Adjusting the batch size may produce better network utilization and produce better performance overall for the application. The larger the batch size, the more messages AMPS will send to the network layer at a time. This can result in fewer packets being sent, and therefore less overhead in the network layer. The effect on performance is generally most noticeable for small messages, where setting a larger batch size will allow several messages to fit into a single packet. For larger messages, a batch size may still improve performance, but the improvement is less noticeable.

In general, 60East recommends setting a batch size that is large enough to produce few partially-filled packets. Bear in mind that AMPS holds the messages in memory while batching them, and the client must also hold the messages in memory while receiving the messages. Using batch sizes that require large amounts of memory for these operations can reduce overall application performance, even if network utilization is good.

For smaller message sizes, 60East recommends using the default batch size, and experimenting with tuning the batch size if performance improvements are necessary. For relatively large messages (especially messages with sizes over 1MB), 60East recommends explicitly setting a batch size of 1 as an initial value, and increasing the batch size only if performance testing with a larger batch size shows improved network utilization or faster overall performance.