Suspicious wait on SQL*NET MESSAGE FROM CLIENT

Hi everybody,

We have a strange performance problem on Oracle 12.1.2.0. When the server is "loaded" we can see high wait values for:

SQL*NET MESSAGE FROM CLIENT

When tracing an application that run on a client machine.

But when the server is "not loaded" the same application functionality traced shows low values for:

SQL*NET MESSAGE FROM CLIENT

We have seen this kind of figure when the server was "loaded":

 

Elapsed times include waiting on following events:

 

  Event waited on Times   Max. Wait  Total Waited

 

----------------------------------------   Waited ----------  ------------

 

  SQL*Net message to client 20945 0.00          0.07

 

  SQL*Net message from client 20945 0.08         88.43

 

  db file sequential read 23 0.17          0.55