When many similar sessions are logged on to perform some quick activity then logged off, the time to establish the session can be much longer than the time to perform the activity. In such cases, session pools can be established. Sessions for a pool are logged on once and re-used for subsequent logons, thus eliminating the overhead of subsequent logons. Session pools are established using the TDP START POOL command. In diagnostic situations, messages can be requested whenever a pool session is assigned or released using the TDP ENABLE POOL STATUS command. It is not recommended during normal operations if the rate of session pool activity is large because of potential adverse impact on system console processing. The TDP DISABLE POOL STATUS command reverses the ENABLE command. When POOL STATUS is enabled, a TDP0802 message indicates when a pool session is assigned, and a TDP0803 message indicates when a pool session is released. It can occasionally be difficult to understand why a session pool session is not assigned, so in such diagnostic situations the TDP ENABLE POOL DETAIL command can be used to produce TDP3100 through TDP3105 messages, which describe the reason a logon was not eligible to use a pool session, or TDP3120 through TDP3127 messages, which describe why a pool session could not be assigned.