This configuration is used when optimizing streaming blob/clob from server to client.
If there were found many small packets, of which sizes are much lower than maximum size of packet possible in the network, it will improve performance of streaming to setting this configuration.
Recommended value of this configuration is maximum packet size possible in the network minus appropriate size for header.
derby.drda.streamOutBufferSize=size of buffer
Dynamic. System values can be changed by using commands or the servlet interface after the Network Server has been started.