Vertica::AggregateFunction Class Reference

Interface for User-Defined Aggregate Function (UDAF). A UDAF operates on one column of data and returns one column of data. More...

Inheritance diagram for Vertica::AggregateFunction:

Collaboration diagram for Vertica::AggregateFunction:

Public Member Functions
virtual void	aggregateArrs (ServerInterface &srvInterface, void **dstTuples, int doff, const void *arr, int stride, const void *rcounts, int rcstride, int count, IntermediateAggs &intAggs, std::vector< int > &intOffsets, BlockReader &arg_reader)=0
void	cancelUDX (ServerInterface &srvInterface)
virtual void	combine (ServerInterface &srvInterface, IntermediateAggs &aggs_output, MultipleIntermediateAggs &aggs_other)=0
virtual void	destroy (ServerInterface &srvInterface, const SizedColumnTypes &argTypes)
virtual void	destroy (ServerInterface &srvInterface, const SizedColumnTypes &argTypes, SessionParamWriterMap &udSessionParams)
virtual void	initAggregate (ServerInterface &srvInterface, IntermediateAggs &aggs)=0
bool	isCanceled () const
virtual void	setup (ServerInterface &srvInterface, const SizedColumnTypes &argTypes)
virtual void	terminate (ServerInterface &srvInterface, BlockWriter &res_writer, IntermediateAggs &aggs)
virtual void	terminate (ServerInterface &srvInterface, BlockWriter &res_writer, IntermediateAggs &aggs, SessionParamWriterMap &udSessionParams)

Static Public Member Functions
static void	updateCols (BlockReader &arg_reader, char *arg, int count, IntermediateAggs &intAggs, char *aggPtr, std::vector< int > &intOffsets)

Protected Member Functions
virtual void	cancel (ServerInterface &srvInterface)

Detailed Description

Interface for User-Defined Aggregate Function (UDAF). A UDAF operates on one column of data and returns one column of data.

An AggregateFunction must have an associated AggregateFunctionFactory.

Member Function Documentation

aggregateArrs()

virtual void Vertica::AggregateFunction::aggregateArrs ( ServerInterface &  srvInterface, void **  dstTuples, int  doff, const void *  arr, int  stride, const void *  rcounts, int  rcstride, int  count, IntermediateAggs &  intAggs, std::vector< int > &  intOffsets, BlockReader &  arg_reader  )

pure virtual

Called by the server to perform aggregation on multiple blocks of data

Note

User should not explicity implement this function. It is implemented by calling the InlineAggregate() macro. User should follow the convention of implementing void aggregate(ServerInterface &srvInterface, BlockReader &arg_reader, IntermediateAggs &aggs) along with initAggregate, combine, and terminate. For references on what a fully implemented Aggregate Function looks like, check the examples in the example folder.

which the inlined aggregateArrs implemention will invoke

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().

combine()

virtual void Vertica::AggregateFunction::combine ( ServerInterface &  srvInterface, IntermediateAggs &  aggs_output, MultipleIntermediateAggs &  aggs_other  )

pure virtual

Called when intermediate aggregates need to be combined with each other

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

initAggregate()

virtual void Vertica::AggregateFunction::initAggregate ( ServerInterface &  srvInterface, IntermediateAggs &  aggs  )

pure virtual

Called by the server to set the starting values of the Intermediate aggregates.

Note

This can be called multiple times on multiple machines, so starting values should be idempotent.

isCanceled()

bool Vertica::UDXObject::isCanceled ( ) const

inlineinherited

Returns

true iff this UDX has been canceled

setup()

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

inlinevirtualinherited

Perform per instance initialization. This function may throw errors.

terminate() [1/2]

virtual void Vertica::AggregateFunction::terminate ( ServerInterface &  srvInterface, BlockWriter &  res_writer, IntermediateAggs &  aggs  )

inlinevirtual

Called by the server to get the output to the aggregate function

Referenced by terminate().

terminate() [2/2]

virtual void Vertica::AggregateFunction::terminate ( ServerInterface &  srvInterface, BlockWriter &  res_writer, IntermediateAggs &  aggs, SessionParamWriterMap &  udSessionParams  )

inlinevirtual

Called by the server to get the output to the aggregate function

updateCols()

void Vertica::AggregateFunction::updateCols ( BlockReader &  arg_reader, char *  arg, int  count, IntermediateAggs &  intAggs, char *  aggPtr, std::vector< int > &  intOffsets  )

static

Helper function for aggregateArrs.

Note

User should not call this function.