Class OptimizerTracer
- java.lang.Object
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- org.apache.derby.impl.sql.compile.OptimizerTracer
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- All Implemented Interfaces:
OptionalTool
public class OptimizerTracer extends java.lang.Object implements OptionalTool
OptionalTool for tracing the Optimizer.
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Constructor Summary
Constructors Constructor Description OptimizerTracer()
0-arg constructor required by the OptionalTool contract
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Method Summary
All Methods Static Methods Instance Methods Concrete Methods Modifier and Type Method 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
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Method Detail
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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 interfaceOptionalTool
- Throws:
java.sql.SQLException
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cantInstantiate
private java.sql.SQLException cantInstantiate(java.lang.String className)
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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 interfaceOptionalTool
- Throws:
java.sql.SQLException
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wrap
private java.sql.SQLException wrap(java.lang.Throwable t)
Wrap an exception in a SQLException
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wrap
private java.sql.SQLException wrap(java.lang.String errorMessage)
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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.
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