IO_CACHE_binlog_cache_storage Class Reference

A binlog cache implementation based on IO_CACHE. More...

#include <binlog_ostream.h>

Inheritance diagram for IO_CACHE_binlog_cache_storage:

Public Member Functions
	IO_CACHE_binlog_cache_storage ()
IO_CACHE_binlog_cache_storage &	operator= (const IO_CACHE_binlog_cache_storage &)=delete
	IO_CACHE_binlog_cache_storage (const IO_CACHE_binlog_cache_storage &)=delete
	~IO_CACHE_binlog_cache_storage () override
bool	open (const char *dir, const char *prefix, my_off_t cache_size, my_off_t max_cache_size)
	Opens the binlog cache. More...
void	close ()
bool	write (const unsigned char *buffer, my_off_t length) override
	Write some bytes into the output stream. More...
bool	truncate (my_off_t offset) override
	Truncate some data at the end of the output stream. More...
bool	seek (my_off_t offset) override
	Put the write position to a given offset. More...
bool	reset ()
	Reset status and drop all data. More...
const char *	tmp_file_name () const
	Returns the file name if a temporary file is opened, otherwise nullptr is returned. More...
size_t	disk_writes () const
	Returns the count of calling temporary file's write() More...
bool	begin (unsigned char **buffer, my_off_t *length)
	Initializes binlog cache for reading and returns the data at the begin. More...
bool	next (unsigned char **buffer, my_off_t *length)
	Returns next piece of data. More...
my_off_t	length () const
bool	flush () override
	Flush data. More...
bool	sync () override
	Sync. More...
Public Member Functions inherited from Truncatable_ostream
	~Truncatable_ostream () override=default
Public Member Functions inherited from Basic_ostream
virtual	~Basic_ostream ()=default

Private Member Functions
bool	enable_encryption ()
	Enable IO Cache temporary file encryption. More...
void	disable_encryption ()
	Disable IO Cache temporary file encryption. More...
bool	setup_ciphers_password ()
	Generate a new password for the temporary file encryption. More...

Private Attributes
IO_CACHE	m_io_cache
my_off_t	m_max_cache_size = 0

Detailed Description

A binlog cache implementation based on IO_CACHE.

Constructor & Destructor Documentation

IO_CACHE_binlog_cache_storage() [1/2]

IO_CACHE_binlog_cache_storage::IO_CACHE_binlog_cache_storage ( )

default

IO_CACHE_binlog_cache_storage() [2/2]

IO_CACHE_binlog_cache_storage::IO_CACHE_binlog_cache_storage ( const IO_CACHE_binlog_cache_storage &  )

delete

~IO_CACHE_binlog_cache_storage()

IO_CACHE_binlog_cache_storage::~IO_CACHE_binlog_cache_storage ( )

override

Member Function Documentation

begin()

bool IO_CACHE_binlog_cache_storage::begin	(	unsigned char **	buffer,
		my_off_t *	length
	)

Initializes binlog cache for reading and returns the data at the begin.

buffer is controlled by binlog cache implementation, so caller should not release it. If the function sets *length to 0 and no error happens, it has reached the end of the cache.

Parameters

[out]	buffer	It points to buffer where data is read.
[out]	length	Length of the data in the buffer.

Return values

false	Success
true	Error

close()

void IO_CACHE_binlog_cache_storage::close

(

)

disable_encryption()

void IO_CACHE_binlog_cache_storage::disable_encryption ( )

private

Disable IO Cache temporary file encryption.

disk_writes()

size_t IO_CACHE_binlog_cache_storage::disk_writes

(

)

const

Returns the count of calling temporary file's write()

enable_encryption()

bool IO_CACHE_binlog_cache_storage::enable_encryption ( )

private

Enable IO Cache temporary file encryption.

Return values

false	Success.
true	Error.

flush()

bool IO_CACHE_binlog_cache_storage::flush ( )

inlineoverridevirtual

Flush data.

Return values

false	Success.
true	Error.

Implements Truncatable_ostream.

length()

my_off_t IO_CACHE_binlog_cache_storage::length

(

)

const

next()

bool IO_CACHE_binlog_cache_storage::next	(	unsigned char **	buffer,
		my_off_t *	length
	)

Returns next piece of data.

buffer is controlled by binlog cache implementation, so caller should not release it. If the function sets length to 0 and no error happens, it has reached the end of the cache.

Parameters

[out]	buffer	It points to buffer where data is read.
[out]	length	Length of the data in the buffer.

Return values

false	Success
true	Error

open()

bool IO_CACHE_binlog_cache_storage::open	(	const char *	dir,
		const char *	prefix,
		my_off_t	cache_size,
		my_off_t	max_cache_size
	)

Opens the binlog cache.

It creates a memory buffer as long as cache_size. The buffer will be extended up to max_cache_size when writing data. The data exceeding max_cache_size will be written into a temporary file.

Parameters

[in]	dir	Where the temporary file will be created
[in]	prefix	Prefix of the temporary file name
[in]	cache_size	Size of the memory buffer.
[in]	max_cache_size	Maximum size of the memory buffer

Return values

false	Success
true	Error

operator=()

IO_CACHE_binlog_cache_storage & IO_CACHE_binlog_cache_storage::operator= ( const IO_CACHE_binlog_cache_storage &  )

delete

reset()

bool IO_CACHE_binlog_cache_storage::reset

(

)

Reset status and drop all data.

It looks like a cache never was used after reset.

seek()

bool IO_CACHE_binlog_cache_storage::seek ( my_off_t  offset )

inlineoverridevirtual

Put the write position to a given offset.

The offset counts from the beginning of the file.

Parameters

[in]

offset

Where the write position will be

Return values

false	Success
true	Error

Implements Truncatable_ostream.

setup_ciphers_password()

bool IO_CACHE_binlog_cache_storage::setup_ciphers_password ( )

private

Generate a new password for the temporary file encryption.

This function is called by reset() that is called every time a transaction commits to cleanup the binary log cache. The file password shall vary not only per temporary file, but also per transaction being committed within a single client connection.

Return values

false	Success.
true	Error.

sync()

bool IO_CACHE_binlog_cache_storage::sync ( )

inlineoverridevirtual

Sync.

Return values

false	Success
true	Error

Implements Truncatable_ostream.

tmp_file_name()

const char * IO_CACHE_binlog_cache_storage::tmp_file_name

(

)

const

Returns the file name if a temporary file is opened, otherwise nullptr is returned.

truncate()

bool IO_CACHE_binlog_cache_storage::truncate ( my_off_t  offset )

overridevirtual

Truncate some data at the end of the output stream.

Parameters

[in]

offset

Where the output stream will be truncated to.

Return values

false	Success
true	Error

Implements Truncatable_ostream.

write()

bool IO_CACHE_binlog_cache_storage::write ( const unsigned char *  buffer, my_off_t  length  )

overridevirtual

Write some bytes into the output stream.

When all data is written into the stream successfully, then it return false. Otherwise, true is returned. It will never returns false when partial data is written into the stream.

Parameters

[in]	buffer	Data to be written
[in]	length	Length of the data

Return values

false	Success.
true	Error.

Implements Basic_ostream.

Member Data Documentation

m_io_cache

IO_CACHE IO_CACHE_binlog_cache_storage::m_io_cache

private

m_max_cache_size

my_off_t IO_CACHE_binlog_cache_storage::m_max_cache_size = 0

private

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

• sql/binlog_ostream.h
• sql/binlog_ostream.cc