Although MQ was built for high transaction volumes, poor architecture and application design can compromise its ability to process messages as fast and effectively as possible. To mitigate potential performance issues, here are several recommendations:
- Message size and length can affect the performance of the application that processes the message, and the network time of data transmission. Send only essential data in the message.
- Use persistent messages for critical or essential data only. Persistent messages are logged to disk and can reduce the performance of your application.
- Retrieving messages from a queue by message or correlation identifiers will reduce application performance. It causes the queue manager to search all messages in the queue until it finds the desired message. If applications have high-performance requirements, applications should be designed to process messages sequentially.
- The MaxMsgLength parameter stores the value for the maximum size of a message allowed on the queue. The 4 MB default can be changed to better align with your application processing needs, which will have the benefit of using system resources in the most efficient manner.
- Ensure that messaging applications are designed to work in parallel with each other and with multiple instances of applications. The queue manager executes one service request within a queue at a given time to maintain integrity. Avoid programs that use numerous MQPUT calls in a sync point without committing them. Affected queues can fill up with messages that are currently inaccessible while other applications or tasks might be waiting to get these messages.
- When applications have intermittent message transmission needs, use the MQPUT1 call to put only one message on the queue. For higher volume applications, where multiple messages are being put, the traditional usage use MQOPEN call followed by a series of MQPUT calls and an MQCLOSE call is more appropriate.
- Keep connections and queues open if you are going to reuse them instead of repeatedly opening and closing, connecting and disconnecting.
- The maximum number of threads an application can run on a system can affect the performance of the solution, especially on Windows.
- Configure channels with a disconnect interval so that they can go inactive when there is no activity on the channel after a period of time. This will reduce overhead and help improve overall performance.
- MQ performance is commonly bound by disk I/O writes. Ensure that the storage team is involved with disk layouts to ensure the fastest reliable disk writes possible.