org.apache.derby.impl.sql.compile

Class OptimizerTracer

java.lang.Object

org.apache.derby.impl.sql.compile.OptimizerTracer

All Implemented Interfaces:

OptionalTool

public class OptimizerTracer
extends java.lang.Object
implements OptionalTool

OptionalTool for tracing the Optimizer.

Constructor Summary

Constructors

Constructor and Description
OptimizerTracer() 0-arg constructor required by the OptionalTool contract

Method Summary

Modifier and Type	Method and Description
private java.sql.SQLException	cantInstantiate(java.lang.String className)
private static Context	getContext(java.lang.String contextID) Privileged lookup of a Context.
void	loadTool(java.lang.String... configurationParameters) Turns on optimizer tracing.
void	unloadTool(java.lang.String... configurationParameters) Print the optimizer trace and turn off tracing.
private java.sql.SQLException	wrap(java.lang.String errorMessage)
private java.sql.SQLException	wrap(java.lang.Throwable t) Wrap an exception in a SQLException

Methods inherited from class java.lang.Object

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

Constructor Detail

OptimizerTracer

public OptimizerTracer()

0-arg constructor required by the OptionalTool contract

Method Detail

loadTool

public void loadTool(java.lang.String... configurationParameters)
              throws java.sql.SQLException

Turns on optimizer tracing. May take optional parameters:

• xml - If the first arg is the "xml" literal, then trace output will be formatted as xml.
• custom, $class - If the first arg is the "custom" literal, then the next arg must be the name of a class which implements org.apache.derby.iapi.sql.compile.OptTrace and which has a 0-arg constructor. The 0-arg constructor is called and the resulting OptTrace object is plugged in to trace the optimizer.

Specified by:

loadTool in interface OptionalTool

Throws:

java.sql.SQLException

cantInstantiate

private java.sql.SQLException cantInstantiate(java.lang.String className)

unloadTool

public void unloadTool(java.lang.String... configurationParameters)
                throws java.sql.SQLException

Print the optimizer trace and turn off tracing. Takes optional parameters:

• fileName - Where to write the optimizer trace. If omitted, the trace is written to System.out.

Specified by:

unloadTool in interface OptionalTool

Throws:

java.sql.SQLException

wrap

private java.sql.SQLException wrap(java.lang.Throwable t)

Wrap an exception in a SQLException

wrap

private java.sql.SQLException wrap(java.lang.String errorMessage)

getContext

private static Context getContext(java.lang.String contextID)

Privileged lookup of a Context. Must be private so that user code can't call this entry point.