Global_read_lock Class Reference

An instance of the global read lock in a connection. More...

#include <sql_class.h>

Public Types
enum	enum_grl_state { GRL_NONE , GRL_ACQUIRED , GRL_ACQUIRED_AND_BLOCKS_COMMIT }

Public Member Functions
	Global_read_lock ()
bool	lock_global_read_lock (THD *thd)
	Take global read lock, wait if there is protection against lock. More...
void	unlock_global_read_lock (THD *thd)
	Unlock global read lock. More...
bool	can_acquire_protection () const
	Check if this connection can acquire protection against GRL and emit error if otherwise. More...
bool	make_global_read_lock_block_commit (THD *thd)
	Make global read lock also block commits. More...
bool	is_acquired () const
void	set_explicit_lock_duration (THD *thd)
	Set explicit duration for metadata locks which are used to implement GRL. More...

Static Public Member Functions
static bool	global_read_lock_active ()
	Used by innodb memcached server to check if any connections have global read lock. More...

Private Attributes
enum_grl_state	m_state
MDL_ticket *	m_mdl_global_shared_lock
	In order to acquire the global read lock, the connection must acquire shared metadata lock in GLOBAL namespace, to prohibit all DDL. More...
MDL_ticket *	m_mdl_blocks_commits_lock
	Also in order to acquire the global read lock, the connection must acquire a shared metadata lock in COMMIT namespace, to prohibit commits. More...

Static Private Attributes
static std::atomic< int32 >	m_atomic_active_requests

Detailed Description

An instance of the global read lock in a connection.

Implemented in lock.cc.

Member Enumeration Documentation

enum_grl_state

enum Global_read_lock::enum_grl_state

Enumerator
GRL_NONE
GRL_ACQUIRED
GRL_ACQUIRED_AND_BLOCKS_COMMIT

Constructor & Destructor Documentation

Global_read_lock()

Global_read_lock::Global_read_lock ( )

inline

Member Function Documentation

can_acquire_protection()

bool Global_read_lock::can_acquire_protection ( ) const

inline

Check if this connection can acquire protection against GRL and emit error if otherwise.

global_read_lock_active()

static bool Global_read_lock::global_read_lock_active ( )

inlinestatic

Used by innodb memcached server to check if any connections have global read lock.

is_acquired()

bool Global_read_lock::is_acquired ( ) const

inline

Member Data Documentation

m_mdl_blocks_commits_lock

MDL_ticket* Global_read_lock::m_mdl_blocks_commits_lock

private

Also in order to acquire the global read lock, the connection must acquire a shared metadata lock in COMMIT namespace, to prohibit commits.

m_mdl_global_shared_lock

MDL_ticket* Global_read_lock::m_mdl_global_shared_lock

private

In order to acquire the global read lock, the connection must acquire shared metadata lock in GLOBAL namespace, to prohibit all DDL.

m_state

enum_grl_state Global_read_lock::m_state

private

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

• sql/sql_class.h
• sql/lock.cc