State_tracker Class Reference

#include <session_tracker.h>

Inheritance diagram for State_tracker:

Public Member Functions
	State_tracker ()
	Constructor. More...
virtual	~State_tracker ()=default
	Destructor. More...
bool	is_enabled () const
	Getters. More...
bool	is_changed () const
virtual bool	enable (THD *thd)=0
	Called in the constructor of THD. More...
virtual bool	check (THD *thd, set_var *var)=0
	To be invoked when the tracker's system variable is checked (ON_CHECK). More...
virtual bool	update (THD *thd)=0
	To be invoked when the tracker's system variable is updated (ON_UPDATE). More...
virtual bool	store (THD *thd, String &buf)=0
	Store changed data into the given buffer. More...
virtual void	mark_as_changed (THD *thd, LEX_CSTRING name)=0
	Mark the entity as changed. More...
virtual void	claim_memory_ownership (bool claim)

Protected Attributes
bool	m_enabled
	Is tracking enabled for a particular session state type ? More...
bool	m_changed
	Has the session state type changed ? More...

Detailed Description

State_tracker

An abstract class that defines the interface for any of the server's 'session state change tracker'. A tracker, however, is a sub- class of this class which takes care of tracking the change in value of a part- icular session state type and thus defines various methods listed in this interface. The change information is later serialized and transmitted to the client through protocol's OK packet.

Tracker system variables :- A tracker is normally mapped to a system variable. So in order to enable, disable or modify the sub-entities of a tracker, the user needs to modify the respective system variable either through SET command or via command line option. As required in system variable handling, this interface also includes two functions to help in the verification of the supplied value (ON_CHECK) and the updation (ON_UPDATE) of the tracker system variable, namely - check() and update().

Constructor & Destructor Documentation

State_tracker()

State_tracker::State_tracker ( )

inline

Constructor.

~State_tracker()

virtual State_tracker::~State_tracker ( )

virtualdefault

Destructor.

Member Function Documentation

check()

virtual bool State_tracker::check ( THD *  thd, set_var *  var  )

pure virtual

To be invoked when the tracker's system variable is checked (ON_CHECK).

Implemented in Current_schema_tracker, Session_gtids_tracker, Session_transaction_state, Session_state_change_tracker, Transaction_state_tracker, and Session_sysvars_tracker.

claim_memory_ownership()

virtual void State_tracker::claim_memory_ownership ( bool  claim )

inlinevirtual

Reimplemented in Session_sysvars_tracker.

enable()

virtual bool State_tracker::enable ( THD *  thd )

pure virtual

Called in the constructor of THD.

Implemented in Session_transaction_state, Session_sysvars_tracker, Current_schema_tracker, Session_gtids_tracker, Session_state_change_tracker, and Transaction_state_tracker.

is_changed()

bool State_tracker::is_changed ( ) const

inline

is_enabled()

bool State_tracker::is_enabled ( ) const

inline

Getters.

mark_as_changed()

virtual void State_tracker::mark_as_changed ( THD *  thd, LEX_CSTRING  name  )

pure virtual

Mark the entity as changed.

Implemented in Session_transaction_state, Session_sysvars_tracker, Current_schema_tracker, Session_gtids_tracker, Session_state_change_tracker, and Transaction_state_tracker.

store()

virtual bool State_tracker::store ( THD *  thd, String &  buf  )

pure virtual

Store changed data into the given buffer.

Implemented in Session_transaction_state, Session_state_change_tracker, Session_sysvars_tracker, Current_schema_tracker, Session_gtids_tracker, and Transaction_state_tracker.

update()

virtual bool State_tracker::update ( THD *  thd )

pure virtual

To be invoked when the tracker's system variable is updated (ON_UPDATE).

Implemented in Session_transaction_state, Session_sysvars_tracker, Current_schema_tracker, Session_gtids_tracker, Session_state_change_tracker, and Transaction_state_tracker.

Member Data Documentation

m_changed

bool State_tracker::m_changed

protected

Has the session state type changed ?

m_enabled

bool State_tracker::m_enabled

protected

Is tracking enabled for a particular session state type ?

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

• sql/session_tracker.h