Hash_slave_rows Class Reference

#include <rpl_utility.h>

Public Member Functions
HASH_ROW_ENTRY *	make_entry ()
	Allocates an empty entry to be added to the hash table. More...
HASH_ROW_ENTRY *	make_entry (const uchar *bi_start, const uchar *bi_ends)
	Allocates an entry to be added to the hash table. More...
bool	put (TABLE *table, MY_BITMAP *cols, HASH_ROW_ENTRY *entry)
	Puts data into the hash table. More...
HASH_ROW_ENTRY *	get (TABLE *table, MY_BITMAP *cols)
	Gets the entry, from the hash table, that matches the data in table->record[0] and signaled using cols. More...
bool	next (HASH_ROW_ENTRY **entry)
	Gets the entry that stands next to the one pointed to by entry. More...
bool	del (HASH_ROW_ENTRY *entry)
	Deletes the entry pointed by entry. More...
bool	init (void)
	Initializes the hash table. More...
bool	deinit (void)
	De-initializes the hash table. More...
bool	is_empty (void)
	Checks if the hash table is empty or not. More...
int	size ()
	Returns the number of entries in the hash table. More...

Private Member Functions
uint	make_hash_key (TABLE *table, MY_BITMAP *cols)
	Auxiliary and internal method used to create an hash key, based on the data in table->record[0] buffer and signaled as used in cols. More...

Private Attributes
malloc_unordered_multimap< uint, std::unique_ptr< HASH_ROW_ENTRY, hash_slave_rows_free_entry > >	m_hash {key_memory_HASH_ROW_ENTRY}
	The hashtable itself. More...

Member Function Documentation

deinit()

bool Hash_slave_rows::deinit

(

void

)

De-initializes the hash table.

Returns

true if something went wrong, false otherwise.

del()

bool Hash_slave_rows::del

(

HASH_ROW_ENTRY *

entry

)

Deletes the entry pointed by entry.

It also frees memory used holding entry contents. This is the way to release memory used for entry, freeing it explicitly with my_free will cause undefined behavior.

Parameters

entry

Pointer to the entry to be deleted.

Returns

true if something went wrong, false otherwise.

get()

HASH_ROW_ENTRY * Hash_slave_rows::get	(	TABLE *	table,
		MY_BITMAP *	cols
	)

Gets the entry, from the hash table, that matches the data in table->record[0] and signaled using cols.

Parameters

table	The table holding the buffer containing data used to make the entry lookup.
cols	Bitmap signaling which columns, from table->record[0], should be used.

Returns

a pointer that will hold a reference to the entry found. If the entry is not found then NULL shall be returned.

Save the search state in case we need to go through entries for the given key.

init()

bool Hash_slave_rows::init

(

void

)

Initializes the hash table.

Hashing commodity structures and functions.

Returns

true if something went wrong, false otherwise.

is_empty()

bool Hash_slave_rows::is_empty

(

void

)

Checks if the hash table is empty or not.

Returns

true if the hash table has zero entries, false otherwise.

make_entry() [1/2]

HASH_ROW_ENTRY * Hash_slave_rows::make_entry

(

)

Allocates an empty entry to be added to the hash table.

It should be called before calling member function put.

Returns

NULL if a problem occurred, a valid pointer otherwise.

make_entry() [2/2]

HASH_ROW_ENTRY * Hash_slave_rows::make_entry	(	const uchar *	bi_start,
		const uchar *	bi_ends
	)

Allocates an entry to be added to the hash table.

It should be called before calling member function put.

Parameters

bi_start	the position to where in the rows buffer the before image begins.
bi_ends	the position to where in the rows buffer the before image ends.

Returns

NULL if a problem occurred, a valid pointer otherwise.

Filling in the preamble.

Filling in the positions.

Filling in the entry

make_hash_key()

uint Hash_slave_rows::make_hash_key ( TABLE *  table, MY_BITMAP *  cols  )

private

Auxiliary and internal method used to create an hash key, based on the data in table->record[0] buffer and signaled as used in cols.

Parameters

table	The table that is being scanned
cols	The read_set bitmap signaling which columns are used.

Returns

the hash key created.

next()

bool Hash_slave_rows::next

(

HASH_ROW_ENTRY **

entry

)

Gets the entry that stands next to the one pointed to by entry.

Before calling this member function, the entry that one uses as parameter must have: 1. been obtained through get() or next() invocations; and 2. must have not been used before in a next() operation.

Parameters

[in,out]

entry

contains a pointer to an entry that we can use to search for another adjacent entry (ie, that shares the same key).

Returns

true if something went wrong, false otherwise. In the case that this entry was already used in a next() operation this member function returns true and does not update the pointer.

Save the search state for next iteration (if any).

put()

bool Hash_slave_rows::put	(	TABLE *	table,
		MY_BITMAP *	cols,
		HASH_ROW_ENTRY *	entry
	)

Puts data into the hash table.

It calculates the key taking the data on TABLE::record as the input for hash computation.

Parameters

table	The table holding the buffer used to calculate the key, ie, table->record[0].
cols	The read_set bitmap signaling which columns are used.
entry	The entry with the values to store.

Returns

true if something went wrong, false otherwise.

Skip blobs and BIT fields from key calculation. Handle X bits. Handle nulled fields. Handled fields not signaled.

size()

int Hash_slave_rows::size

(

)

Returns the number of entries in the hash table.

Returns

the number of entries in the hash table.

Member Data Documentation

m_hash

malloc_unordered_multimap< uint, std::unique_ptr<HASH_ROW_ENTRY, hash_slave_rows_free_entry> > Hash_slave_rows::m_hash {key_memory_HASH_ROW_ENTRY}

private

The hashtable itself.

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

• sql/rpl_utility.h
• sql/rpl_utility.cc