The Parse Ratio alarm is raised when the ratio of parse calls to execute calls exceeds a threshold. A parse call is required to prepare a SQL statement for execution. Once parsed, a statement can be executed many times. Excessive parsing wastes CPU and can cause latch contention.
Note: By default, the Parse Ratio alarm is disabled. It has been superseded (Oracle 10.2 and later) by the Total Parse Wait Time Ratio alarm. You may want to enable the Parse Ratio alarm when monitoring earlier versions of Oracle systems.