MDL_context_backup_manager::MDL_context_backup Class Reference

Wrapper around MDL_context class which allows to store it in backup manager's collection. More...

Inheritance diagram for MDL_context_backup_manager::MDL_context_backup:

Public Member Functions
	MDL_context_backup ()
	~MDL_context_backup () override
MDL_context *	get_context ()
Public Member Functions inherited from MDL_context_owner
virtual	~MDL_context_owner ()=default

Private Member Functions
void	enter_cond (mysql_cond_t *, mysql_mutex_t *, const PSI_stage_info *, PSI_stage_info *, const char *, const char *, int) override
	Enter a condition wait. More...
void	exit_cond (const PSI_stage_info *, const char *, const char *, int) override
	End a wait on a condition. More...
int	is_killed () const override
	Has the owner thread been killed? More...
bool	might_have_commit_order_waiters () const final
	Indicates that owner thread might have some commit order (non-MDL) waits for it which are still taken into account by MDL deadlock detection, even in cases when it doesn't have any MDL locks acquired and therefore can't have any MDL waiters. More...
THD *	get_thd () override
void	notify_shared_lock (MDL_context_owner *, bool) override
bool	notify_hton_pre_acquire_exclusive (const MDL_key *, bool *) override
	Notify/get permission from interested storage engines before acquiring exclusive lock for the key. More...
void	notify_hton_post_release_exclusive (const MDL_key *) override
	Notify interested storage engines that we have just released exclusive lock for the key. More...
uint	get_rand_seed () const override
	Get random seed specific to this THD to be used for initialization of PRNG for the MDL_context. More...
bool	is_connected (bool=false) override
	Does the owner still have connection to the client? More...

Private Attributes
MDL_context	m_context

Detailed Description

Wrapper around MDL_context class which allows to store it in backup manager's collection.

Also implements MDL_context_owner interface and serves as owner for stored MDL_context.

Constructor & Destructor Documentation

MDL_context_backup()

MDL_context_backup_manager::MDL_context_backup::MDL_context_backup ( )

inline

~MDL_context_backup()

MDL_context_backup_manager::MDL_context_backup::~MDL_context_backup ( )

inlineoverride

Member Function Documentation

enter_cond()

void MDL_context_backup_manager::MDL_context_backup::enter_cond ( mysql_cond_t *  cond, mysql_mutex_t *  mutex, const PSI_stage_info *  stage, PSI_stage_info *  old_stage, const char *  src_function, const char *  src_file, int  src_line  )

inlineoverrideprivatevirtual

Enter a condition wait.

For enter_cond() / exit_cond() to work the mutex must be held before enter_cond(); this mutex must then be released before exit_cond(). Usage must be: lock mutex; enter_cond(); your code; unlock mutex; exit_cond().

Parameters

	cond	the condition to wait on
	mutex	the associated mutex
[in]	stage	the stage to enter, or NULL
[out]	old_stage	the previous stage, or NULL
	src_function	function name of the caller
	src_file	file name of the caller
	src_line	line number of the caller

See also

ENTER_COND(), THD::enter_cond()

EXIT_COND(), THD::exit_cond()

Implements MDL_context_owner.

exit_cond()

void MDL_context_backup_manager::MDL_context_backup::exit_cond ( const PSI_stage_info *  stage, const char *  src_function, const char *  src_file, int  src_line  )

inlineoverrideprivatevirtual

End a wait on a condition.

Parameters

[in]	stage	the new stage to enter
	src_function	function name of the caller
	src_file	file name of the caller
	src_line	line number of the caller

See also

ENTER_COND(), THD::enter_cond()

EXIT_COND(), THD::exit_cond()

Implements MDL_context_owner.

get_context()

MDL_context * MDL_context_backup_manager::MDL_context_backup::get_context ( )

inline

get_rand_seed()

uint MDL_context_backup_manager::MDL_context_backup::get_rand_seed ( ) const

inlineoverrideprivatevirtual

Get random seed specific to this THD to be used for initialization of PRNG for the MDL_context.

Implements MDL_context_owner.

get_thd()

THD * MDL_context_backup_manager::MDL_context_backup::get_thd ( )

inlineoverrideprivatevirtual

Warning

Since there is no THD associated with This method returns nullptr unconditionally.

Implements MDL_context_owner.

is_connected()

bool MDL_context_backup_manager::MDL_context_backup::is_connected ( bool  = false )

inlineoverrideprivatevirtual

Does the owner still have connection to the client?

Implements MDL_context_owner.

is_killed()

int MDL_context_backup_manager::MDL_context_backup::is_killed ( ) const

inlineoverrideprivatevirtual

Has the owner thread been killed?

Implements MDL_context_owner.

might_have_commit_order_waiters()

bool MDL_context_backup_manager::MDL_context_backup::might_have_commit_order_waiters ( ) const

inlinefinalprivatevirtual

Indicates that owner thread might have some commit order (non-MDL) waits for it which are still taken into account by MDL deadlock detection, even in cases when it doesn't have any MDL locks acquired and therefore can't have any MDL waiters.

Note

It is important for this check to be non-racy and quick (perhaps at expense of being pretty pessimistic), so it can be used to make decisions reliably about whether we can skip deadlock detection in some cases.

Implements MDL_context_owner.

notify_hton_post_release_exclusive()

void MDL_context_backup_manager::MDL_context_backup::notify_hton_post_release_exclusive ( const MDL_key *  mdl_key )

inlineoverrideprivatevirtual

Notify interested storage engines that we have just released exclusive lock for the key.

Implements MDL_context_owner.

notify_hton_pre_acquire_exclusive()

bool MDL_context_backup_manager::MDL_context_backup::notify_hton_pre_acquire_exclusive ( const MDL_key *  mdl_key, bool *  victimized  )

inlineoverrideprivatevirtual

Notify/get permission from interested storage engines before acquiring exclusive lock for the key.

The returned argument 'victimized' specify reason for lock not granted. If 'true', lock was refused in an attempt to resolve a possible MDL->GSL deadlock. Locking may then be retried.

Returns

False if notification was successful and it is OK to acquire lock, True if one of SEs asks to abort lock acquisition.

Implements MDL_context_owner.

notify_shared_lock()

void MDL_context_backup_manager::MDL_context_backup::notify_shared_lock ( MDL_context_owner *  in_use, bool  needs_thr_lock_abort  )

inlineoverrideprivatevirtual

See also

THD::notify_shared_lock()

Implements MDL_context_owner.

Member Data Documentation

m_context

MDL_context MDL_context_backup_manager::MDL_context_backup::m_context

private

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

• sql/mdl_context_backup.cc