About Message Compression
Message compression is especially useful when messages will be stored on the server (persistent queue messages, or topics with durable subscribers). Setting compression ensures that messages will take less memory space in storage. When messages are compressed and then stored, they are handled by the server in the compressed form. Compression assures that the messages will usually consume less space on disk and will be handled faster by the EMS server.
The compression option only compresses the body of a message. Headers and properties are never compressed. It is best to use compression when the message bodies will be large and the messages will be stored on a server.
When messages will not be stored, compression is not as useful. Compression normally takes time, and therefore the time to send or publish and receive compressed messages is generally longer than the time to send the same messages uncompressed. There is little purpose to message compression for small messages that are not be stored by the server.