cudf::hash_join Class Reference

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

#include <join.hpp>

Public Types
using	impl_type = typename cudf::detail::hash_join< cudf::hashing::detail::MurmurHash3_x86_32< cudf::hash_value_type > >
	Implementation type.

Public Member Functions
	hash_join (hash_join const &)=delete
	hash_join (hash_join &&)=delete
hash_join &	operator= (hash_join const &)=delete
hash_join &	operator= (hash_join &&)=delete
	hash_join (cudf::table_view const &build, null_equality compare_nulls, rmm::cuda_stream_view stream=cudf::get_default_stream())
	Construct a hash join object for subsequent probe calls. More...
	hash_join (cudf::table_view const &build, nullable_join has_nulls, null_equality compare_nulls, rmm::cuda_stream_view stream=cudf::get_default_stream())
	Construct a 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 (cudf::table_view const &probe, std::optional< std::size_t > output_size={}, rmm::cuda_stream_view stream=cudf::get_default_stream(), rmm::device_async_resource_ref mr=rmm::mr::get_current_device_resource()) const
std::pair< std::unique_ptr< rmm::device_uvector< size_type > >, std::unique_ptr< rmm::device_uvector< size_type > > >	left_join (cudf::table_view const &probe, std::optional< std::size_t > output_size={}, rmm::cuda_stream_view stream=cudf::get_default_stream(), rmm::device_async_resource_ref mr=rmm::mr::get_current_device_resource()) const
std::pair< std::unique_ptr< rmm::device_uvector< size_type > >, std::unique_ptr< rmm::device_uvector< size_type > > >	full_join (cudf::table_view const &probe, std::optional< std::size_t > output_size={}, rmm::cuda_stream_view stream=cudf::get_default_stream(), rmm::device_async_resource_ref mr=rmm::mr::get_current_device_resource()) const
std::size_t	inner_join_size (cudf::table_view const &probe, rmm::cuda_stream_view stream=cudf::get_default_stream()) const
std::size_t	left_join_size (cudf::table_view const &probe, rmm::cuda_stream_view stream=cudf::get_default_stream()) const
std::size_t	full_join_size (cudf::table_view const &probe, rmm::cuda_stream_view stream=cudf::get_default_stream(), rmm::device_async_resource_ref mr=rmm::mr::get_current_device_resource()) const

Detailed Description

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

This class enables the hash join scheme that builds hash table once, and probes as many times as needed (possibly in parallel).

Definition at line 296 of file join.hpp.

Constructor & Destructor Documentation

hash_join() [1/2]

cudf::hash_join::hash_join	(	cudf::table_view const &	build,
		null_equality	compare_nulls,
		rmm::cuda_stream_view	stream = cudf::get_default_stream()
	)

Construct a hash join object for subsequent probe calls.

Note

The hash_join object must not outlive the table viewed by build, else behavior is undefined.

Parameters

build	The build table, from which the hash table is built
compare_nulls	Controls whether null join-key values should match or not
stream	CUDA stream used for device memory operations and kernel launches

hash_join() [2/2]

cudf::hash_join::hash_join	(	cudf::table_view const &	build,
		nullable_join	has_nulls,
		null_equality	compare_nulls,
		rmm::cuda_stream_view	stream = cudf::get_default_stream()
	)

Construct a hash join object for subsequent probe calls.

Note

The hash_join object must not outlive the table viewed by build, else behavior is undefined.

Parameters

build	The build table, from which the hash table is built
compare_nulls	Controls whether null join-key values should match or not
stream	CUDA stream used for device memory operations and kernel launches
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

Member Function Documentation

full_join()

std::pair<std::unique_ptr<rmm::device_uvector<size_type> >, std::unique_ptr<rmm::device_uvector<size_type> > > cudf::hash_join::full_join	(	cudf::table_view const &	probe,
		std::optional< std::size_t >	output_size = {},
		rmm::cuda_stream_view	stream = cudf::get_default_stream(),
		rmm::device_async_resource_ref	mr = rmm::mr::get_current_device_resource()
	)		const

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

See also

cudf::full_join(). Behavior is undefined if the provided output_size is smaller than the actual output size.

Parameters

probe	The probe table, from which the tuples are probed
output_size	Optional value which allows users to specify the exact output size
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.

Exceptions

cudf::logic_error

If the input probe table has nulls while this hash_join object was not constructed with null check.

Returns

A pair of columns [left_indices, right_indices] that can be used to construct the result of performing a full join between two tables with build and probe as the join keys .

full_join_size()

std::size_t cudf::hash_join::full_join_size	(	cudf::table_view const &	probe,
		rmm::cuda_stream_view	stream = cudf::get_default_stream(),
		rmm::device_async_resource_ref	mr = rmm::mr::get_current_device_resource()
	)		const

Returns the exact number of matches (rows) when performing a full join with the specified probe table.

Parameters

probe	The probe table, from which the tuples are probed
stream	CUDA stream used for device memory operations and kernel launches
mr	Device memory resource used to allocate the intermediate table and columns' device memory.

Exceptions

cudf::logic_error

If the input probe table has nulls while this hash_join object was not constructed with null check.

Returns

The exact number of output when performing a full join between two tables with build and probe as the join keys .

inner_join()

std::pair<std::unique_ptr<rmm::device_uvector<size_type> >, std::unique_ptr<rmm::device_uvector<size_type> > > cudf::hash_join::inner_join	(	cudf::table_view const &	probe,
		std::optional< std::size_t >	output_size = {},
		rmm::cuda_stream_view	stream = cudf::get_default_stream(),
		rmm::device_async_resource_ref	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(). Behavior is undefined if the provided output_size is smaller than the actual output size.

Parameters

probe	The probe table, from which the tuples are probed
output_size	Optional value which allows users to specify the exact output size
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.

Exceptions

cudf::logic_error

If the input probe table has nulls while this hash_join object was not constructed with null check.

Returns

A pair of columns [left_indices, right_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 .

inner_join_size()

std::size_t cudf::hash_join::inner_join_size	(	cudf::table_view const &	probe,
		rmm::cuda_stream_view	stream = cudf::get_default_stream()
	)		const

Returns the exact number of matches (rows) when performing an inner join with the specified probe table.

Parameters

probe	The probe table, from which the tuples are probed
stream	CUDA stream used for device memory operations and kernel launches

Exceptions

cudf::logic_error

If the input probe table has nulls while this hash_join object was not constructed with null check.

Returns

The exact number of output when performing an inner join between two tables with build and probe as the join keys .

left_join()

std::pair<std::unique_ptr<rmm::device_uvector<size_type> >, std::unique_ptr<rmm::device_uvector<size_type> > > cudf::hash_join::left_join	(	cudf::table_view const &	probe,
		std::optional< std::size_t >	output_size = {},
		rmm::cuda_stream_view	stream = cudf::get_default_stream(),
		rmm::device_async_resource_ref	mr = rmm::mr::get_current_device_resource()
	)		const

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

See also

cudf::left_join(). Behavior is undefined if the provided output_size is smaller than the actual output size.

Parameters

probe	The probe table, from which the tuples are probed
output_size	Optional value which allows users to specify the exact output size
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.

Exceptions

cudf::logic_error

If the input probe table has nulls while this hash_join object was not constructed with null check.

Returns

A pair of columns [left_indices, right_indices] that can be used to construct the result of performing a left join between two tables with build and probe as the join keys.

left_join_size()

std::size_t cudf::hash_join::left_join_size	(	cudf::table_view const &	probe,
		rmm::cuda_stream_view	stream = cudf::get_default_stream()
	)		const

Returns the exact number of matches (rows) when performing a left join with the specified probe table.

Parameters

probe	The probe table, from which the tuples are probed
stream	CUDA stream used for device memory operations and kernel launches

Exceptions

cudf::logic_error

If the input probe table has nulls while this hash_join object was not constructed with null check.

Returns

The exact number of output when performing a left join between two tables with build and probe as the join keys .

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

• join.hpp