An error handler which converts, if possible, ER_LOCK_DEADLOCK error that can occur when we are trying to acquire a metadata lock to a request for back-off and re-start of open_tables() process. More...

Inheritance diagram for MDL_deadlock_handler:

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Public Member Functions
	MDL_deadlock_handler (Open_table_context *ot_ctx_arg)

bool	handle_condition (THD , uint sql_errno, const char , Sql_condition::enum_severity_level , const char ) override
	Handle a sql condition. More...

Private Attributes
Open_table_context *	m_ot_ctx
	Open table context to be used for back-off request. More...

bool	m_is_active
	Indicates that we are already in the process of handling ER_LOCK_DEADLOCK error. More...

Additional Inherited Members
Protected Member Functions inherited from Internal_error_handler
	Internal_error_handler ()

Internal_error_handler *	prev_internal_handler () const

virtual	~Internal_error_handler ()=default

Detailed Description

An error handler which converts, if possible, ER_LOCK_DEADLOCK error that can occur when we are trying to acquire a metadata lock to a request for back-off and re-start of open_tables() process.

Constructor & Destructor Documentation

◆ MDL_deadlock_handler()

MDL_deadlock_handler::MDL_deadlock_handler ( Open_table_context * ot_ctx_arg )

inline

Member Function Documentation

◆ handle_condition()

bool MDL_deadlock_handler::handle_condition	(	THD *	thd,
		uint	sql_errno,
		const char *	sqlstate,
		Sql_condition::enum_severity_level *	level,
		const char *	msg
	)

inlineoverridevirtual

Handle a sql condition.

This method can be implemented by a subclass to achieve any of the following:

mask a warning/error internally, prevent exposing it to the user,
mask a warning/error and throw another one instead. When this method returns true, the sql condition is considered 'handled', and will not be propagated to upper layers. It is the responsibility of the code installing an internal handler to then check for trapped conditions, and implement logic to recover from the anticipated conditions trapped during runtime.

This mechanism is similar to C++ try/throw/catch:

'try' correspond to THD::push_internal_handler(),
'throw' correspond to my_error(), which invokes my_message_sql(),
'catch' correspond to checking how/if an internal handler was invoked, before removing it from the exception stack with THD::pop_internal_handler().

Parameters

thd	the calling thread
sql_errno	the error number for the condition raised.
sqlstate	the SQLSTATE for the condition raised.
level	the severity level for the condition raised.
msg	the error message for the condition raised.

Returns: true if the condition is handled

Implements Internal_error_handler.

Member Data Documentation

◆ m_is_active

bool MDL_deadlock_handler::m_is_active

private

Indicates that we are already in the process of handling ER_LOCK_DEADLOCK error.

Allows to re-emit the error from the error handler without falling into infinite recursion.

◆ m_ot_ctx

Open_table_context* MDL_deadlock_handler::m_ot_ctx

private

Open table context to be used for back-off request.

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

sql/sql_base.cc

Public Member Functions

Private Attributes

Additional Inherited Members