Explain_join class produces EXPLAIN output for JOINs. More...

Inheritance diagram for anonymous_namespace{opt_explain.cc}::Explain_join:

Public Member Functions
	Explain_join (THD explain_thd_arg, const THD query_thd_arg, Query_block *query_block_arg, bool need_tmp_table_arg, bool need_order_arg, bool distinct_arg)

Public Member Functions inherited from anonymous_namespace{opt_explain.cc}::Explain
virtual	~Explain ()=default

bool	send ()
	Explain class main function. More...

bool	can_print_clauses () const
	Tells if it is allowed to print the WHERE / GROUP BY / etc clauses. More...

Protected Member Functions
bool	shallow_explain () override
	Explain everything but subqueries. More...

bool	explain_table_name () override

bool	explain_join_type () override

bool	explain_key_and_len () override
	fill col_key and and col_key_len fields together More...

bool	explain_ref () override

bool	explain_rows_and_filtered () override
	fill col_rows and col_filtered fields together More...

bool	explain_extra () override

bool	explain_select_type () override

bool	explain_id () override

bool	explain_modify_flags () override

bool	can_walk_clauses () override
	Returns true if the WHERE, ORDER BY, GROUP BY, etc clauses can safely be traversed: it means that we can iterate through them (no element is added/removed/replaced); the internal details of an element can change though (in particular if that element is an Item_subselect). More...

Protected Member Functions inherited from anonymous_namespace{opt_explain.cc}::Explain_table_base
	Explain_table_base (enum_parsing_context context_type_arg, THD const explain_thd_arg, const THD query_thd_arg, Query_block query_block_arg=nullptr, TABLE const table_arg=nullptr)

bool	explain_partitions () override

bool	explain_possible_keys () override

bool	explain_key_parts (int key, uint key_parts)

bool	explain_key_and_len_quick (AccessPath *range_scan)

bool	explain_key_and_len_index (int key)

bool	explain_key_and_len_index (int key, uint key_length, uint key_parts)

bool	explain_extra_common (int range_scan_type, uint keyno)

bool	explain_tmptable_and_filesort (bool need_tmp_table_arg, bool need_sort_arg)

Protected Member Functions inherited from anonymous_namespace{opt_explain.cc}::Explain
	Explain (enum_parsing_context context_type_arg, THD explain_thd_arg, const THD query_thd_arg, Query_block *query_block_arg)

bool	explain_subqueries ()
	Explain the rest of things after the `shallow_explain()` call. More...

bool	mark_subqueries (Item item, qep_row destination)
	Qualify subqueries with WHERE/HAVING/ORDER BY/GROUP BY clause type marker. More...

bool	prepare_columns ()
	Pre-calculate table property values for further EXPLAIN output. More...

bool	push_extra (Extra_tag tag)
	Push a part of the "extra" column into formatter. More...

bool	push_extra (Extra_tag tag, const String &arg)
	Push a part of the "extra" column into formatter. More...

bool	push_extra (Extra_tag tag, const char *arg)
	Push a part of the "extra" column into formatter. More...

virtual enum_parsing_context	get_subquery_context (Query_expression *unit) const

Private Member Functions
bool	begin_sort_context (Explain_sort_clause clause, enum_parsing_context ctx)

bool	end_sort_context (Explain_sort_clause clause, enum_parsing_context ctx)

bool	begin_simple_sort_context (Explain_sort_clause clause, enum_parsing_context ctx)

bool	end_simple_sort_context (Explain_sort_clause clause, enum_parsing_context ctx)

bool	explain_qep_tab (size_t tab_num)

Private Attributes
bool	need_tmp_table
	add "Using temporary" to "extra" if true More...

bool	need_order
	add "Using filesort"" to "extra" if true More...

const bool	distinct
	add "Distinct" string to "extra" column if true More...

JOIN *	join
	current JOIN More...

int	range_scan_type
	current range scan type, really an AccessPath::Type More...

Additional Inherited Members
Protected Attributes inherited from anonymous_namespace{opt_explain.cc}::Explain_table_base
QEP_TAB *	tab {nullptr}
	The QEP_TAB which we are currently explaining. More...

const TABLE *	table {nullptr}

join_type	type {JT_UNKNOWN}

AccessPath *	range_scan_path {nullptr}

Item *	condition {nullptr}

bool	dynamic_range {false}

Table_ref *	table_ref {nullptr}

bool	skip_records_in_range {false}

bool	reversed_access {false}

Key_map	usable_keys

Protected Attributes inherited from anonymous_namespace{opt_explain.cc}::Explain
THD *const	explain_thd
	cached THD which runs the EXPLAIN command More...

const THD *	query_thd
	THD which runs the query to be explained. More...

const CHARSET_INFO *const	cs
	cached pointer to system_charset_info More...

Query_block *const	query_block
	Cached Query_block of the explained query. More...

Explain_format *const	fmt
	shortcut for thd->lex->explain_format More...

enum_parsing_context	context_type
	associated value for struct. explain More...

bool	order_list
	if query block has ORDER BY More...

const bool	explain_other
	if we explain other thread than us More...

Detailed Description

Explain_join class produces EXPLAIN output for JOINs.

Constructor & Destructor Documentation

◆ Explain_join()

anonymous_namespace{opt_explain.cc}::Explain_join::Explain_join	(	THD *	explain_thd_arg,
		const THD *	query_thd_arg,
		Query_block *	query_block_arg,
		bool	need_tmp_table_arg,
		bool	need_order_arg,
		bool	distinct_arg
	)

inline

Member Function Documentation

◆ begin_simple_sort_context()

bool Explain_join::begin_simple_sort_context	(	Explain_sort_clause	clause,
		enum_parsing_context	ctx
	)

private

◆ begin_sort_context()

bool Explain_join::begin_sort_context	(	Explain_sort_clause	clause,
		enum_parsing_context	ctx
	)

private

◆ can_walk_clauses()

bool anonymous_namespace{opt_explain.cc}::Explain_join::can_walk_clauses ( )

inlineoverrideprotectedvirtual

Returns true if the WHERE, ORDER BY, GROUP BY, etc clauses can safely be traversed: it means that we can iterate through them (no element is added/removed/replaced); the internal details of an element can change though (in particular if that element is an Item_subselect).

By default, if we are explaining another connection, this is not safe.

Reimplemented from anonymous_namespace{opt_explain.cc}::Explain.

◆ end_simple_sort_context()

bool Explain_join::end_simple_sort_context	(	Explain_sort_clause	clause,
		enum_parsing_context	ctx
	)

private

◆ end_sort_context()

bool Explain_join::end_sort_context	(	Explain_sort_clause	clause,
		enum_parsing_context	ctx
	)

private

◆ explain_extra()

bool Explain_join::explain_extra ( )

overrideprotectedvirtual

Reimplemented from anonymous_namespace{opt_explain.cc}::Explain.

◆ explain_id()

bool Explain_join::explain_id ( )

overrideprotectedvirtual

Reimplemented from anonymous_namespace{opt_explain.cc}::Explain.

◆ explain_join_type()

bool Explain_join::explain_join_type ( )

overrideprotectedvirtual

Reimplemented from anonymous_namespace{opt_explain.cc}::Explain.

◆ explain_key_and_len()

bool Explain_join::explain_key_and_len ( )

overrideprotectedvirtual

fill col_key and and col_key_len fields together

Reimplemented from anonymous_namespace{opt_explain.cc}::Explain.

◆ explain_modify_flags()

bool Explain_join::explain_modify_flags ( )

overrideprotectedvirtual

Reimplemented from anonymous_namespace{opt_explain.cc}::Explain.

◆ explain_qep_tab()

bool Explain_join::explain_qep_tab ( size_t tab_num )

private

◆ explain_ref()

bool Explain_join::explain_ref ( )

overrideprotectedvirtual

Reimplemented from anonymous_namespace{opt_explain.cc}::Explain.

◆ explain_rows_and_filtered()

bool Explain_join::explain_rows_and_filtered ( )

overrideprotectedvirtual

fill col_rows and col_filtered fields together

Reimplemented from anonymous_namespace{opt_explain.cc}::Explain.

◆ explain_select_type()

bool Explain_join::explain_select_type ( )

overrideprotectedvirtual

Reimplemented from anonymous_namespace{opt_explain.cc}::Explain.

◆ explain_table_name()

bool Explain_join::explain_table_name ( )

overrideprotectedvirtual

Reimplemented from anonymous_namespace{opt_explain.cc}::Explain.

◆ shallow_explain()

bool Explain_join::shallow_explain ( )

overrideprotectedvirtual

Explain everything but subqueries.

Reimplemented from anonymous_namespace{opt_explain.cc}::Explain.

Member Data Documentation

◆ distinct

const bool anonymous_namespace{opt_explain.cc}::Explain_join::distinct

private

add "Distinct" string to "extra" column if true

◆ join

JOIN* anonymous_namespace{opt_explain.cc}::Explain_join::join

private

current JOIN

◆ need_order

bool anonymous_namespace{opt_explain.cc}::Explain_join::need_order

private

add "Using filesort"" to "extra" if true

◆ need_tmp_table

bool anonymous_namespace{opt_explain.cc}::Explain_join::need_tmp_table

private

add "Using temporary" to "extra" if true

◆ range_scan_type

int anonymous_namespace{opt_explain.cc}::Explain_join::range_scan_type

private

current range scan type, really an AccessPath::Type

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

sql/opt_explain.cc

Public Member Functions

Protected Member Functions

Private Member Functions

Private Attributes

Additional Inherited Members

Detailed Description

Constructor & Destructor Documentation

◆ Explain_join()

Member Function Documentation

◆ begin_simple_sort_context()

◆ begin_sort_context()

◆ can_walk_clauses()

◆ end_simple_sort_context()

◆ end_sort_context()

◆ explain_extra()

◆ explain_id()

◆ explain_join_type()

◆ explain_key_and_len()

◆ explain_modify_flags()

◆ explain_qep_tab()

◆ explain_ref()

◆ explain_rows_and_filtered()

◆ explain_select_type()

◆ explain_table_name()

◆ shallow_explain()

Member Data Documentation

◆ distinct

◆ join

◆ need_order

◆ need_tmp_table

◆ range_scan_type