Connection_handler_manager Class Reference

This is a singleton class that provides various connection management related functionalities, most importantly dispatching new connections to the currently active Connection_handler. More...

#include <connection_handler_manager.h>

Public Types
enum	scheduler_types { SCHEDULER_ONE_THREAD_PER_CONNECTION = 0 , SCHEDULER_NO_THREADS , SCHEDULER_TYPES_COUNT }
	thread_handling enumeration. More...

Public Member Functions
bool	valid_connection_count ()
	Check if the current number of connections are below or equal the value given by the max_connections server system variable. More...
bool	check_and_incr_conn_count (bool ignore_max_connection_count, bool internal_session)
	Increment connection count if max_connections is not exceeded. More...
void	inc_aborted_connects ()
ulong	aborted_connects () const
ulong	connection_errors_max_connection () const
void	load_connection_handler (Connection_handler *conn_handler)
	Dynamically load a connection handler implemented as a plugin. More...
bool	unload_connection_handler ()
	Unload the connection handler previously loaded by load_connection_handler(). More...
void	process_new_connection (Channel_info *channel_info)
	Process a new incoming connection. More...

Static Public Member Functions
static Connection_handler_manager *	get_instance ()
	Singleton method to return an instance of this class. More...
static bool	init ()
	Initialize the connection handler manager. More...
static void	destroy_instance ()
	Destroy the singleton instance. More...
static void	reset_max_used_connections ()
	Reset the max_used_connections counter to the number of current connections. More...
static void	dec_connection_count ()
	Decrease the number of current connections. More...
static ulong	get_incoming_connects ()
static void	wait_till_no_connection ()
	Waits until all connections are done with their job. More...
static uint	get_connection_count ()
	Return number of connections in thread-safe way. More...

Static Public Attributes
static uint	connection_count = 0
static ulong	max_used_connections = 0
static ulong	max_used_connections_time = 0
static std::atomic_ulong	incoming_connection_count = 0
static ulong	thread_handling
static THD_event_functions *	event_functions = nullptr
static THD_event_functions *	saved_event_functions
static uint	max_threads = 0
	Maximum number of threads that can be created by the current connection handler. More...

Private Member Functions
	Connection_handler_manager (Connection_handler *connection_handler)
	Constructor to instantiate an instance of this class. More...
	~Connection_handler_manager ()
	Connection_handler_manager (const Connection_handler_manager &)
Connection_handler_manager &	operator= (const Connection_handler_manager &)

Private Attributes
Connection_handler *	m_connection_handler
Connection_handler *	m_saved_connection_handler
ulong	m_saved_thread_handling
ulong	m_aborted_connects
ulong	m_connection_errors_max_connection

Static Private Attributes
static Connection_handler_manager *	m_instance = nullptr
static mysql_mutex_t	LOCK_connection_count
static mysql_cond_t	COND_connection_count

Detailed Description

This is a singleton class that provides various connection management related functionalities, most importantly dispatching new connections to the currently active Connection_handler.

Member Enumeration Documentation

scheduler_types

enum Connection_handler_manager::scheduler_types

thread_handling enumeration.

The default of –thread-handling is the first one in the thread_handling_names array, this array has to be consistent with the order in this array, so to change default one has to change the first entry in this enum and the first entry in the thread_handling_names array.

Note

The last entry of the enumeration is also used to mark the thread handling as dynamic. In this case the name of the thread handling is fetched from the name of the plugin that implements it.

Enumerator
SCHEDULER_ONE_THREAD_PER_CONNECTION
SCHEDULER_NO_THREADS
SCHEDULER_TYPES_COUNT

Constructor & Destructor Documentation

Connection_handler_manager() [1/2]

Connection_handler_manager::Connection_handler_manager ( Connection_handler *  connection_handler )

inlineprivate

Constructor to instantiate an instance of this class.

~Connection_handler_manager()

Connection_handler_manager::~Connection_handler_manager ( )

inlineprivate

Connection_handler_manager() [2/2]

Connection_handler_manager::Connection_handler_manager ( const Connection_handler_manager &  )

private

Member Function Documentation

aborted_connects()

ulong Connection_handler_manager::aborted_connects ( ) const

inline

check_and_incr_conn_count()

bool Connection_handler_manager::check_and_incr_conn_count	(	bool	ignore_max_connection_count,
		bool	internal_session
	)

Increment connection count if max_connections is not exceeded.

Parameters

ignore_max_connection_count	true if checking for a limit specified by the max-connections server option should be skipped.
internal_session	true if this is an internal session created by the session service. If this is the case, we will not count this as an incoming connection.

Return values

true	max_connections NOT exceeded false max_connections reached

connection_errors_max_connection()

ulong Connection_handler_manager::connection_errors_max_connection ( ) const

inline

Note

This is a dirty read.

dec_connection_count()

static void Connection_handler_manager::dec_connection_count ( )

inlinestatic

Decrease the number of current connections.

destroy_instance()

void Connection_handler_manager::destroy_instance ( )

static

Destroy the singleton instance.

get_connection_count()

static uint Connection_handler_manager::get_connection_count ( )

inlinestatic

Return number of connections in thread-safe way.

get_incoming_connects()

static ulong Connection_handler_manager::get_incoming_connects ( )

inlinestatic

get_instance()

static Connection_handler_manager * Connection_handler_manager::get_instance ( )

inlinestatic

Singleton method to return an instance of this class.

inc_aborted_connects()

void Connection_handler_manager::inc_aborted_connects ( )

inline

init()

bool Connection_handler_manager::init ( )

static

Initialize the connection handler manager.

Must be called before get_instance() can be used.

Returns

true if initialization failed, false otherwise.

load_connection_handler()

void Connection_handler_manager::load_connection_handler

(

Connection_handler *

conn_handler

)

Dynamically load a connection handler implemented as a plugin.

The current connection handler will be saved so that it can later be restored by unload_connection_handler().

operator=()

Connection_handler_manager & Connection_handler_manager::operator= ( const Connection_handler_manager &  )

private

process_new_connection()

void Connection_handler_manager::process_new_connection

(

Channel_info *

channel_info

)

Process a new incoming connection.

Parameters

channel_info

Pointer to Channel_info object containing connection channel information.

reset_max_used_connections()

void Connection_handler_manager::reset_max_used_connections ( )

static

Reset the max_used_connections counter to the number of current connections.

unload_connection_handler()

bool Connection_handler_manager::unload_connection_handler

(

)

Unload the connection handler previously loaded by load_connection_handler().

The previous connection handler will be restored.

Returns

true if unload failed (no previous connection handler was found).

valid_connection_count()

bool Connection_handler_manager::valid_connection_count

(

)

Check if the current number of connections are below or equal the value given by the max_connections server system variable.

Returns

true if a new connection can be accepted, false otherwise.

wait_till_no_connection()

void Connection_handler_manager::wait_till_no_connection ( )

static

Waits until all connections are done with their job.

In other words, wat till connection_count to become zero.

Member Data Documentation

COND_connection_count

mysql_cond_t Connection_handler_manager::COND_connection_count

staticprivate

connection_count

uint Connection_handler_manager::connection_count = 0

static

event_functions

THD_event_functions * Connection_handler_manager::event_functions = nullptr

static

incoming_connection_count

std::atomic_ulong Connection_handler_manager::incoming_connection_count = 0

static

LOCK_connection_count

mysql_mutex_t Connection_handler_manager::LOCK_connection_count

staticprivate

m_aborted_connects

ulong Connection_handler_manager::m_aborted_connects

private

m_connection_errors_max_connection

ulong Connection_handler_manager::m_connection_errors_max_connection

private

m_connection_handler

Connection_handler* Connection_handler_manager::m_connection_handler

private

m_instance

Connection_handler_manager * Connection_handler_manager::m_instance = nullptr

staticprivate

m_saved_connection_handler

Connection_handler* Connection_handler_manager::m_saved_connection_handler

private

m_saved_thread_handling

ulong Connection_handler_manager::m_saved_thread_handling

private

max_threads

uint Connection_handler_manager::max_threads = 0

static

Maximum number of threads that can be created by the current connection handler.

Must be static as it is used by the signal handler.

max_used_connections

ulong Connection_handler_manager::max_used_connections = 0

static

max_used_connections_time

ulong Connection_handler_manager::max_used_connections_time = 0

static

saved_event_functions

THD_event_functions * Connection_handler_manager::saved_event_functions

static

Initial value:

=
    nullptr

thread_handling

ulong Connection_handler_manager::thread_handling

static

Initial value:

=
    SCHEDULER_ONE_THREAD_PER_CONNECTION

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

• sql/conn_handler/connection_handler_manager.h
• sql/conn_handler/connection_handler_manager.cc