Class OptimizerTrace

java.lang.Object
org.apache.derby.iapi.db.OptimizerTrace

public class OptimizerTrace extends Object

This class provides static methods for controlling the optimizer tracing in a Derby database.

  • Constructor Details

    • OptimizerTrace

      public OptimizerTrace()
  • Method Details

    • setOptimizerTrace

      public static void setOptimizerTrace(boolean onOrOff)
      Turn default optimizer tracing on or off.
      Parameters:
      onOrOff - Whether to turn optimizer tracing on (true) or off (false).
    • setOptimizerTracer

      public static void setOptimizerTracer(OptTrace tracer)
      Install an optimizer tracer (to enable tracing) or uninstall the current optimizer tracer (to disable tracing).
      Parameters:
      tracer - Null if tracing is being turned off, otherwise an optimizer tracer
    • getOptimizerTracer

      public static OptTrace getOptimizerTracer()
      Get the current optimizer tracer, if any.
    • getOptimizerTraceOutput

      public static String getOptimizerTraceOutput()
      Get the optimizer trace output for the last optimized query as a String.
      Returns:
      The optimizer trace output for the last optimized query as a String. Null will be returned if optimizer trace output is off or not supported or no trace output was found or an exception occurred.