#include <mdl.h>

Public Types
enum	enum_mdl_namespace { GLOBAL = 0, SCHEMA, TABLE, FUNCTION, PROCEDURE, TRIGGER, EVENT, COMMIT, NAMESPACE_END }

Public Member Functions
const uchar *	ptr () const
uint	length () const
const char *	db_name () const
uint	db_name_length () const
const char *	name () const
uint	name_length () const
enum_mdl_namespace	mdl_namespace () const
void	mdl_key_init (enum_mdl_namespace mdl_namespace, const char db, const char name)
void	mdl_key_init (const MDL_key *rhs)
bool	is_equal (const MDL_key *rhs) const
int	cmp (const MDL_key *rhs) const
	MDL_key (const MDL_key *rhs)
	MDL_key (enum_mdl_namespace namespace_arg, const char db_arg, const char name_arg)
const PSI_stage_info *	get_wait_state_name () const

Detailed Description

Metadata lock object key.

A lock is requested or granted based on a fully qualified name and type. E.g. They key for a table consists of <0 (=table)>+<database>+

Elsewhere in the comments this triple will be referred to simply as "key" or "name".

Definition at line 278 of file mdl.h.

Member Enumeration Documentation

Object namespaces. Sic: when adding a new member to this enum make sure to update m_namespace_to_wait_state_name array in mdl.cc!

Different types of objects exist in different namespaces

TABLE is for tables and views.
FUNCTION is for stored functions.
PROCEDURE is for stored procedures.
TRIGGER is for triggers.
EVENT is for event scheduler events Note that although there isn't metadata locking on triggers, it's necessary to have a separate namespace for them since MDL_key is also used outside of the MDL subsystem.

Definition at line 300 of file mdl.h.

int MDL_key::cmp ( const MDL_key * rhs ) const

inline

Compare two MDL keys lexicographically.

Definition at line 363 of file mdl.h.

const PSI_stage_info* MDL_key::get_wait_state_name ( ) const

inline

Get thread state name to be used in case when we have to wait on resource identified by key.

Definition at line 389 of file mdl.h.

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inline

Construct a metadata lock key from a triplet (mdl_namespace, database and name).

Remarks

The key for a table is <mdl_namespace>+<database name>="">+

mdl_namespace Id of namespace of object to be locked

Parameters

db	Name of database to which the object belongs
name	Name of of the object
key	Where to store the the MDL key.

Definition at line 334 of file mdl.h.

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