org.apache.derby.iapi.db

Class OptimizerTrace

java.lang.Object

org.apache.derby.iapi.db.OptimizerTrace

public class OptimizerTrace
extends java.lang.Object

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

Constructor Summary

Constructors

Constructor and Description
OptimizerTrace()

Method Summary

Modifier and Type	Method and Description
static java.lang.String	getOptimizerTraceOutput() Get the optimizer trace output for the last optimized query as a String.
static OptTrace	getOptimizerTracer() Get the current optimizer tracer, if any.
static void	setOptimizerTrace(boolean onOrOff) Turn default optimizer tracing on or off.
static void	setOptimizerTracer(OptTrace tracer) Install an optimizer tracer (to enable tracing) or uninstall the current optimizer tracer (to disable tracing).

Methods inherited from class java.lang.Object

equals, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Detail

OptimizerTrace

public OptimizerTrace()

Method Detail

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 java.lang.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.