Vertica::TransformFunction Class Reference

Interface for User-Defined Transform Function (UDTF). A UDTF operates on a table segment and returns zero or more rows of data. More...

Inheritance diagram for Vertica::TransformFunction:

Collaboration diagram for Vertica::TransformFunction:

Public Member Functions
void	cancelUDX (ServerInterface &srvInterface)
virtual void	destroy (ServerInterface &srvInterface, const SizedColumnTypes &argTypes)
virtual void	destroy (ServerInterface &srvInterface, const SizedColumnTypes &argTypes, SessionParamWriterMap &udSessionParams)
bool	isCanceled () const
virtual void	processPartition (ServerInterface &srvInterface, PartitionReader &input_reader, PartitionWriter &output_writer)=0
virtual void	setup (ServerInterface &srvInterface, const SizedColumnTypes &argTypes)

Protected Member Functions
virtual void	cancel (ServerInterface &srvInterface)

Detailed Description

Interface for User-Defined Transform Function (UDTF). A UDTF operates on a table segment and returns zero or more rows of data.

UDTFs can only be used in the SELECT list of a query. UDTFs are cancelable.

A TransformFunction must have an associated TransformFunctionFactory.

Member Function Documentation

cancel()

virtual void Vertica::UDXObject::cancel ( ServerInterface &  srvInterface )

inlineprotectedvirtualinherited

Cancel callback to be overridden by the UDX. Called when the query running the UDX has been canceled.

Note

• This method will be invoked at most once per UDX object. Once a UDX object has been canceled, it will never be un-canceled.

• This method may be called from a separate thread, concurrently with other methods of this UDX object (but never the constructor or destructor). Implementations must be thread-safe with all methods of this UDX.

• This method will be invoked for either an explicit user cancel, or in the event of an error during query execution.

Referenced by Vertica::UDXObject::cancelUDX().

cancelUDX()

void Vertica::UDXObject::cancelUDX ( ServerInterface &  srvInterface )

inlineinherited

Cancel callback invoked when the query running the UDX has been canceled. See cancel().

destroy() [1/2]

virtual void Vertica::UDXFunction::destroy ( ServerInterface &  srvInterface, const SizedColumnTypes &  argTypes  )

inlinevirtualinherited

Perform per instance destruction. This function may throw errors

Referenced by Vertica::UDXFunction::destroy().

destroy() [2/2]

virtual void Vertica::UDXFunction::destroy ( ServerInterface &  srvInterface, const SizedColumnTypes &  argTypes, SessionParamWriterMap &  udSessionParams  )

inlinevirtualinherited

Perform per instance destruction and write session parameters to be used by UDxs that are invoked after this one returns. This function may throw errors

isCanceled()

bool Vertica::UDXObject::isCanceled ( ) const

inlineinherited

Returns

true iff this UDX has been canceled

processPartition()

virtual void Vertica::TransformFunction::processPartition ( ServerInterface &  srvInterface, PartitionReader &  input_reader, PartitionWriter &  output_writer  )

pure virtual

Invoke a user defined transform on a set of rows. As the name suggests, a batch of rows are passed in for every invocation to amortize performance.

Parameters

srvInterface	a ServerInterface object used to communicate with Vertica
input_reader	input rows
output_writer	output location

setup()

virtual void Vertica::UDXFunction::setup ( ServerInterface &  srvInterface, const SizedColumnTypes &  argTypes  )

inlinevirtualinherited

Perform per instance initialization. This function may throw errors.