cudf::distinct_hash_join< HasNested > Class Template Reference

Distinct hash join that builds hash table in creation and probes results in subsequent *_join member functions. More...

#include <join.hpp>

Public Member Functions
	distinct_hash_join (distinct_hash_join const &)=delete
	distinct_hash_join (distinct_hash_join &&)=delete
distinct_hash_join &	operator= (distinct_hash_join const &)=delete
distinct_hash_join &	operator= (distinct_hash_join &&)=delete
	distinct_hash_join (cudf::table_view const &build, cudf::table_view const &probe, nullable_join has_nulls=nullable_join::YES, null_equality compare_nulls=null_equality::EQUAL, rmm::cuda_stream_view stream=cudf::get_default_stream())
	Constructs a distinct hash join object for subsequent probe calls. More...
std::pair< std::unique_ptr< rmm::device_uvector< size_type > >, std::unique_ptr< rmm::device_uvector< size_type > > >	inner_join (rmm::cuda_stream_view stream=cudf::get_default_stream(), rmm::mr::device_memory_resource *mr=rmm::mr::get_current_device_resource()) const
	Returns the row indices that can be used to construct the result of performing an inner join between two tables. More...
std::unique_ptr< rmm::device_uvector< size_type > >	left_join (rmm::cuda_stream_view stream=cudf::get_default_stream(), rmm::mr::device_memory_resource *mr=rmm::mr::get_current_device_resource()) const
	Returns the build table indices that can be used to construct the result of performing a left join between two tables. More...

Detailed Description

template<cudf::has_nested HasNested>
class cudf::distinct_hash_join< HasNested >

Distinct hash join that builds hash table in creation and probes results in subsequent *_join member functions.

Note

Behavior is undefined if the build table contains duplicates.

All NaNs are considered as equal

Template Parameters

HasNested

Flag indicating whether there are nested columns in build/probe table

Definition at line 462 of file join.hpp.

Constructor & Destructor Documentation

distinct_hash_join()

template<cudf::has_nested HasNested>

cudf::distinct_hash_join< HasNested >::distinct_hash_join	(	cudf::table_view const &	build,
		cudf::table_view const &	probe,
		nullable_join	has_nulls = nullable_join::YES,
		null_equality	compare_nulls = null_equality::EQUAL,
		rmm::cuda_stream_view	stream = cudf::get_default_stream()
	)

Constructs a distinct hash join object for subsequent probe calls.

Parameters

build	The build table that contains distinct elements
probe	The probe table, from which the keys are probed
has_nulls	Flag to indicate if there exists any nulls in the build table or any probe table that will be used later for join
compare_nulls	Controls whether null join-key values should match or not
stream	CUDA stream used for device memory operations and kernel launches

Member Function Documentation

inner_join()

template<cudf::has_nested HasNested>

std::pair<std::unique_ptr<rmm::device_uvector<size_type> >, std::unique_ptr<rmm::device_uvector<size_type> > > cudf::distinct_hash_join< HasNested >::inner_join	(	rmm::cuda_stream_view	stream = cudf::get_default_stream(),
		rmm::mr::device_memory_resource *	mr = rmm::mr::get_current_device_resource()
	)		const

Returns the row indices that can be used to construct the result of performing an inner join between two tables.

See also

cudf::inner_join().

Parameters

stream	CUDA stream used for device memory operations and kernel launches
mr	Device memory resource used to allocate the returned indices' device memory.

Returns

A pair of columns [build_indices, probe_indices] that can be used to construct the result of performing an inner join between two tables with build and probe as the join keys.

left_join()

template<cudf::has_nested HasNested>

std::unique_ptr<rmm::device_uvector<size_type> > cudf::distinct_hash_join< HasNested >::left_join	(	rmm::cuda_stream_view	stream = cudf::get_default_stream(),
		rmm::mr::device_memory_resource *	mr = rmm::mr::get_current_device_resource()
	)		const

Returns the build table indices that can be used to construct the result of performing a left join between two tables.

Note

For a given row index i of the probe table, the resulting build_indices[i] contains the row index of the matched row from the build table if there is a match. Otherwise, contains JoinNoneValue.

Parameters

stream	CUDA stream used for device memory operations and kernel launches
mr	Device memory resource used to allocate the returned table and columns' device memory.

Returns

A build_indices column that can be used to construct the result of performing a left join between two tables with build and probe as the join keys.

---

The documentation for this class was generated from the following file:

• join.hpp