SQL Guide : Tuning performance with SQL : Waiting on events
  
Waiting on events
In many programs, you may have to wait for a particular condition to occur before you can perform a certain task. In some cases, you may use a “while” loop to check whether the condition has occurred. solidDB® provides Events, which in some cases allow you to avoid wasting CPU time spinning in a loop waiting for a condition.
One (or more) clients or threads can wait on an event, and another client or thread can post that event. For example, several threads might wait for a sensor to get a new piece of data. Another thread (working with that sensor) can post an event indicating that the data is available. For more information about events, see Events and various sections of solidDB® SQL statements, including CREATE EVENT.
See also
Tuning performance with SQL