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

OptimizerTrace()

Method Summary

static java.lang.String	getOptimizerTraceOutput() Get the optimizer trace output for the last optimized query as a String.
static void	nullifyTrace() Null out the optimizer trace.
static boolean	setOptimizerTrace(boolean onOrOff) Control whether or not optimizer trace is on.
static boolean	setOptimizerTraceHtml(boolean onOrOff) Control whether or not optimizer trace is generated in html.
static boolean	writeOptimizerTraceOutputHtml(java.lang.String fileName) Send the optimizer trace output for the last optimized query to a file with a .html extension.

Methods inherited from class java.lang.Object

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

Constructor Detail

OptimizerTrace

public OptimizerTrace()

Method Detail

setOptimizerTrace

public static boolean setOptimizerTrace(boolean onOrOff)

Control whether or not optimizer trace is on.

Parameters:

onOrOff - Whether to turn optimizer trace on (true) or off (false).

Returns:

Whether or not the call was successful. (false will be returned when optimizer tracing is not supported.)

nullifyTrace

public static void nullifyTrace()
                         throws java.sql.SQLException

Null out the optimizer trace.

Throws:

java.sql.SQLException

setOptimizerTraceHtml

public static boolean setOptimizerTraceHtml(boolean onOrOff)

Control whether or not optimizer trace is generated in html.

Parameters:

onOrOff - Whether or not optimizer trace will be in html (true) or not (false).

Returns:

Whether or not the call was successful. (false will be returned when optimizer tracing is not supported.)

getOptimizerTraceOutput

public static java.lang.String getOptimizerTraceOutput()

Get the optimizer trace output for the last optimized query as a String. If optimizer trace html is on, then the String will contain the html tags.

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.

writeOptimizerTraceOutputHtml

public static boolean writeOptimizerTraceOutputHtml(java.lang.String fileName)

Send the optimizer trace output for the last optimized query to a file with a .html extension. If optimizer trace html is on, then the output will contain the html tags.

Parameters:

fileName - The name of the file to write to. (.html extension will be added.)

Returns:

Whether or not the request was successful. false mayl be returned for a number of reasons, including if optimizer trace output is off or not supported or no trace output was found or an exception occurred.