@sateesh it is a configuration on the queue. The default is 10,000. You can configure this in either the WebManager GUI or via CLI.
Still, 25GB for a single client application sounds pretty crazy! I’m wondering if there is something else going on here. By my quick calcs, that many consumers pulling as many 2kB messages they can, should only consumer about 1GB of RAM.
Did the performance with SdkPerf scale linearly with the number of client connections? 60 msg/s @ 2kB is pretty bad. Are you in the cloud? I’m wondering about the disk performance…?