Query_result_explain_into_var Class Reference

Wrapper class for writing EXPLAIN output to a user variable. More...

#include <opt_explain.h>

Inheritance diagram for Query_result_explain_into_var:

Public Member Functions
	Query_result_explain_into_var (Query_expression *expr, Query_result *child, std::string_view variable_name)
bool	send_result_set_metadata (THD *, const mem_root_deque< Item * > &, uint) override
bool	send_data (THD *thd, const mem_root_deque< Item * > &items) override
bool	send_eof (THD *thd) override
Public Member Functions inherited from Query_result_explain
	Query_result_explain (Query_expression *unit_arg, Query_result *interceptor_arg)
bool	use_protocol_adapter () const override
Public Member Functions inherited from Query_result_send
	Query_result_send ()
bool	send_result_set_metadata (THD *thd, const mem_root_deque< Item * > &list, uint flags) override
bool	send_data (THD *thd, const mem_root_deque< Item * > &items) override
bool	send_eof (THD *thd) override
bool	check_supports_cursor () const override
	Check if this query result set supports cursors. More...
void	abort_result_set (THD *thd) override
void	cleanup () override
	Cleanup after this execution. More...
bool	use_protocol_adapter () const override
	An alternative implementation may provide an optimized protocol adapter for this object. More...
Public Member Functions inherited from Query_result
	Query_result ()
virtual	~Query_result ()=default
virtual bool	needs_file_privilege () const
virtual bool	change_query_result (THD *, Query_result *)
	Change wrapped Query_result. More...
virtual bool	need_explain_interceptor () const
virtual bool	create_table_for_query_block (THD *)
	Create table, only needed to support CREATE TABLE ... SELECT. More...
virtual uint	field_count (const mem_root_deque< Item * > &fields) const
virtual bool	reset ()
	Cleanup after one execution of the unit, to be ready for a next execution inside the same statement. More...
virtual bool	use_protocol_wrapper () const
virtual void	set_limit (ha_rows)
	Only overridden (and non-empty) for Query_result_union, q.v. More...
virtual Server_side_cursor *	cursor () const

Private Attributes
std::string_view	m_variable_name

Additional Inherited Members
Public Attributes inherited from Query_result
ha_rows	estimated_rowcount
	Number of records estimated in this result. More...
double	estimated_cost
	Cost to execute the subquery which produces this result. More...
Protected Member Functions inherited from Query_result_explain
bool	prepare (THD *thd, const mem_root_deque< Item * > &list, Query_expression *u) override
	Perform preparation specific to the query expression or DML statement. More...
bool	start_execution (THD *thd) override
	Prepare for execution of the query expression or DML statement. More...
void	cleanup () override
	Cleanup after this execution. More...
Protected Attributes inherited from Query_result_explain
Query_result *	interceptor
	Pointer to underlying Query_result_insert, Query_result_update or Query_result_delete object. More...
Protected Attributes inherited from Query_result
Query_expression *	unit

Detailed Description

Wrapper class for writing EXPLAIN output to a user variable.

This class overrides Query_result_send::send_data() to write the output of the EXPLAIN query to the user variable specified by m_variable_name.

Constructor & Destructor Documentation

Query_result_explain_into_var()

Query_result_explain_into_var::Query_result_explain_into_var ( Query_expression *  expr, Query_result *  child, std::string_view  variable_name  )

inline

Member Function Documentation

send_data()

bool Query_result_explain_into_var::send_data ( THD *  thd, const mem_root_deque< Item * > &  items  )

overridevirtual

Implements Query_result.

send_eof()

bool Query_result_explain_into_var::send_eof ( THD *  thd )

overridevirtual

Implements Query_result.

send_result_set_metadata()

bool Query_result_explain_into_var::send_result_set_metadata ( THD *  , const mem_root_deque< Item * > &  , uint    )

inlineoverridevirtual

Implements Query_result.

Member Data Documentation

m_variable_name

std::string_view Query_result_explain_into_var::m_variable_name

private

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

• sql/opt_explain.h
• sql/opt_explain.cc