Chapter 2. Changes in 3.0.0

2.1. Known Issues

qpid-cpp

1095809 - Unwanted and misleading SSL info messages on qpidd service startup

It was discovered that misleading SSL messages appeared in logs if the HA Module was loaded into the Broker and logging was turned up to INFO or higher. Messages similar to the following are displayed: "2014-04-29 10:17:34 [Security] info SSL connector not enabled, you must set QPID_SSL_CERT_DB to enable it." This message is harmless. The message is not referring to the regular SSL functionality of the broker: it is referring to the outgoing client functionality of the HA client. There is no workaround to this issue, except to disregard this message if it appears in the logs.
1129997 - qpid c++ client AMQP 1.0 throughput performance regression

It was discovered that if the capacity (property of qpid::messaging::Receiver class) and ack-frequency (setting on qpid-recv utility) were both at 100, there was a sudden drop in throughput. Reducing the ack-frequency or increasing the capacity, even by a very small amount, was found to make a considerable difference in throughput.

In general, a value higher than 100 is recommended to test throughput. A suggested value for the qpid::messaging::Receiver capacity parameter would be between 500-1000. A lower value is suitable for the qpid-recv utility ack-frequency parameter (which sets the frequency at which qpid::messaging::Session::acknowledge() is called). For example, acknowledging every 10 messages is unlikely to negatively impact the performance.