#include <hashjoin.h>

Inheritance diagram for HashJoin:

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Collaboration diagram for HashJoin:

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Public Member Functions
	HashJoin (FileId outer_id, FileId inner_id, FileId result_id, std::vector< FieldId > outer_fields, std::vector< FieldId > inner_fields, std::uint32_t num_buckets, std::string temp_path, Catalog catalog, BufferManager buf_mgr, FileManager *file_mgr)
	Constructor for the join operater using a hash join algorithm. Sets up the state for a single join operation using the specified state.

	~HashJoin ()
	Destructor for hashjoin class.

void	runOperation ()
	Performs the join operation using the hash join alogrithm.

Public Member Functions inherited from Join
	Join (FileId outer_id, FileId inner_id, FileId result_id, std::vector< FieldId > outer_fields, std::vector< FieldId > inner_fields, Catalog *catalog)
	Constructor for Join operation. Join subclasses use this constructor.

	~Join ()
	Destructor for the Join Operation.

Public Member Functions inherited from Operation
	Operation (FileId result_id, Catalog *catalog)
	Constructor for the Operation class. Because Operation is an abstract class, an object cannot be created, but this constructor is used by derived classes.

virtual	~Operation ()
	Destructor for the Operation class. Cleans up dynamic memory in result state.

Protected Member Functions
std::uint32_t	hash1 (Record *rec, bool is_outer)
	Performs the first hash function on the inputted record.

void	_createTempFiles ()
	Performs the set up phase of hash join, creating temporary hashed files to be used by hash join algorithm.

void	_firstHash (bool is_outer)
	Performs the initial hashing of each relation for the first step of hash join.

void	_secondHash ()
	Performs the second hashing of each relation for the second step of hash join.

RecordId	_part1 (Record record, bool is_outer, BlockHeapFileScanner scanner)
	Performs the main looping functionality for first hash.

void	cleanup ()
	Function that cleans up state and deletes all allocated memory. It will be called once by one thread when any function throws an error.

Protected Member Functions inherited from Operation
void	_initState (FileId file_id, std::vector< FieldId > fields, fileState *state)
	Performs the file and temporary record setup for relational operators.

void	_delState (fileState *file_state)
	Deletes objects created in relop structs.

Protected Attributes
BufferManager *	buf_mgr

FileManager *	file_mgr

std::vector< HeapFile * >	outer_partitions

std::vector< HeapFile * >	inner_partitions

std::uint32_t	num_buckets

std::vector< std::pair< HeapPage *, PageId > >	hash_table

std::string	temp_path
	Holds the path to which the temp files should be saved. "/local/" is recommended for performance.

std::uint32_t	result_num

Protected Attributes inherited from Join
fileState	outer

fileState	inner

std::vector< FieldId >	outer_fields

std::vector< FieldId >	inner_fields

Protected Attributes inherited from Operation
fileState	result_state

Catalog *	catalog

Detailed Description

SwatDB HashJoin Class.

Constructor & Destructor Documentation

◆ HashJoin()

HashJoin::HashJoin	(	FileId	outer_id,
		FileId	inner_id,
		FileId	result_id,
		std::vector< FieldId >	outer_fields,
		std::vector< FieldId >	inner_fields,
		std::uint32_t	num_buckets,
		std::string	temp_path,
		Catalog *	catalog,
		BufferManager *	buf_mgr,
		FileManager *	file_mgr
	)

Constructor for the join operater using a hash join algorithm. Sets up the state for a single join operation using the specified state.

Precondition: The types of the fields being joined on have the same type.

Postcondition: The set up for the hash join is complete.

Parameters

outer_id.	FileId of the outer relation file.
inner_id.	FileId of the inner relation file.
result_id.	FileId of the result relation file.
outer_field_ids.	Vector of FieldIds corresponding to the join field in outer_rel
inner_field_ids.	Vector of FieldIds corresponding to the join field in inner_rel
num_buckets.	Amount of partitions for the hashing
catalog.	Pointer to the catalog of the Swatdb object
buf_mgr.	Pointer to the buffer manager of the dbms
temp_path.	filename for temporary files

Member Function Documentation

◆ _createTempFiles()

void HashJoin::_createTempFiles ( )

protected

Performs the set up phase of hash join, creating temporary hashed files to be used by hash join algorithm.

Parameters

tid.	Thread id of the thread performing the function

◆ _firstHash()

void HashJoin::_firstHash ( bool is_outer )

protected

Performs the initial hashing of each relation for the first step of hash join.

Parameters

tid.	Thread id of the thread performing this specific round of \ computation.
is_outer.	Boolean indicator of which relation is being hashed

◆ _part1()

RecordId HashJoin::_part1	(	Record *	record,
		bool	is_outer,
		BlockHeapFileScanner *	scanner
	)

protected

Performs the main looping functionality for first hash.

Parameters

record.	Pointer to the record object which holds the current rec
is_outer.	Boolean indicator of current relation
scanner.	Scanner object which is iterating over the relation

Returns: rid. Record id

◆ cleanup()

void HashJoin::cleanup ( )

protected

Function that cleans up state and deletes all allocated memory. It will be called once by one thread when any function throws an error.

Postcondition: All allocated state has been deleted.

◆ hash1()

std::uint32_t HashJoin::hash1	(	Record *	rec,
		bool	is_outer
	)

protected

Performs the first hash function on the inputted record.

Returns: std::uint32_t corresponding to the bucket.

◆ runOperation()

void HashJoin::runOperation ( )

virtual

Performs the join operation using the hash join alogrithm.

Precondition: Join state correctly initialized

Postcondition: HeapFile contains all matching results. The object should be destroyed, state is invalid.

Implements Operation.

Reimplemented in ParallelHashJoin.

Member Data Documentation

◆ buf_mgr

BufferManager* HashJoin::buf_mgr

protected

Stores a pointer to the buffer manager

◆ file_mgr

FileManager* HashJoin::file_mgr

protected

Stores a pointer to the file manager for file creation

◆ hash_table

std::vector<std::pair<HeapPage *, PageId> > HashJoin::hash_table

protected

Stores the hash table

◆ inner_partitions

std::vector<HeapFile *> HashJoin::inner_partitions

protected

Vector of HeapFile pointers for temporary files corresponding to the inner relation.

◆ num_buckets

std::uint32_t HashJoin::num_buckets

protected

The number of partitions the relations are being hashed into.

◆ outer_partitions

std::vector<HeapFile *> HashJoin::outer_partitions

protected

Vector of HeapFile pointers for temporary files corresponding to the outer relation.

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

hashjoin.h

Public Member Functions

Protected Member Functions

Protected Attributes

Detailed Description

Constructor & Destructor Documentation

◆ HashJoin()

Member Function Documentation

◆ _createTempFiles()

◆ _firstHash()

◆ _part1()

◆ cleanup()

◆ hash1()

◆ runOperation()

Member Data Documentation

◆ buf_mgr

◆ file_mgr

◆ hash_table

◆ inner_partitions

◆ num_buckets

◆ outer_partitions