Writes all error messages to error log as well. SC903 - Send all logged messages to the client. . SC906 - Log session startup and shutdown. Writes to error log. Default is 10, valid range is 1-10000.
Larger values means that the optimizer runs longer before the 'good enough' criteria is satisfied.
If this is a repeat query then this space is saved for as long as the repeat query is active. Otherwise it is reused by the next query. Default is 10. Valid range 3-15 inclusive. Suggest prime number like 11.