HashJoinChunk Class Reference

#include <hash_join_chunk.h>

Public Member Functions
	HashJoinChunk ()=default
	HashJoinChunk (HashJoinChunk &&other)
	HashJoinChunk (const HashJoinChunk &obj)=delete
HashJoinChunk &	operator= (HashJoinChunk &&other)
	~HashJoinChunk ()
bool	Init (const pack_rows::TableCollection &tables, bool uses_match_flags)
	Initialize this HashJoinChunk. More...
ha_rows	num_rows () const
bool	WriteRowToChunk (String *buffer, bool matched)
	Write a row to the HashJoinChunk. More...
bool	LoadRowFromChunk (String *buffer, bool *matched)
	Read a row from the HashJoinChunk and put it in the record buffer. More...
bool	Rewind ()
	Flush the file buffer, and prepare the file for reading. More...

Private Attributes
pack_rows::TableCollection	m_tables
ha_rows	m_num_rows {0}
IO_CACHE	m_file
bool	m_uses_match_flags {false}

Constructor & Destructor Documentation

HashJoinChunk() [1/3]

HashJoinChunk::HashJoinChunk ( )

default

HashJoinChunk() [2/3]

HashJoinChunk::HashJoinChunk

(

HashJoinChunk &&

other

)

HashJoinChunk() [3/3]

HashJoinChunk::HashJoinChunk ( const HashJoinChunk &  obj )

delete

~HashJoinChunk()

HashJoinChunk::~HashJoinChunk

(

)

Member Function Documentation

Init()

bool HashJoinChunk::Init	(	const pack_rows::TableCollection &	tables,
		bool	uses_match_flags
	)

Initialize this HashJoinChunk.

Parameters

tables	The tables to store row data from. Which column we store in the chunk file is determined by each tables read set.
uses_match_flags	Whether each row should be prefixed with a match flag, saying whether the row had a matching row.

Returns

true if the initialization failed.

LoadRowFromChunk()

bool HashJoinChunk::LoadRowFromChunk	(	String *	buffer,
		bool *	matched
	)

Read a row from the HashJoinChunk and put it in the record buffer.

The function will read a row from file on disk and put it in the record buffers (table->record[0]) in the provided tables. The file on disk should already be pointing to the start of a row.

Parameters

	buffer	a buffer that is used when copying data from the chunk file to the tables. Note that any existing data in "buffer" is overwritten.
[out]	matched	whether this row has seen a matching row from the other input. The flag is only restored if 'm_uses_match_flags' is set, and if the row comes from the probe input.

Return values

true

on error.

num_rows()

ha_rows HashJoinChunk::num_rows ( ) const

inline

Returns

the number of rows in this HashJoinChunk

operator=()

HashJoinChunk & HashJoinChunk::operator=

(

HashJoinChunk &&

other

)

Rewind()

bool HashJoinChunk::Rewind

(

)

Flush the file buffer, and prepare the file for reading.

Return values

true

on error

WriteRowToChunk()

bool HashJoinChunk::WriteRowToChunk	(	String *	buffer,
		bool	matched
	)

Write a row to the HashJoinChunk.

Read the row that lies in the record buffer (record[0]) of the given tables and write it out to the underlying file. If the QEP_TAB signals that the row ID should be kept, it is also written out. Note that TABLE::read_set is used to signal which columns that should be written to the chunk.

Parameters

buffer	a buffer that is used when copying data from the tables to the chunk file. Note that any existing data in "buffer" is overwritten.
matched	whether this row has seen a matching row from the other input. The flag is only written if 'm_uses_match_flags' is set, and if the row comes from the probe input.

Return values

true

on error.

Member Data Documentation

m_file

IO_CACHE HashJoinChunk::m_file

private

m_num_rows

ha_rows HashJoinChunk::m_num_rows {0}

private

m_tables

pack_rows::TableCollection HashJoinChunk::m_tables

private

m_uses_match_flags

bool HashJoinChunk::m_uses_match_flags {false}

private

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

• sql/iterators/hash_join_chunk.h
• sql/iterators/hash_join_chunk.cc