Explain_table class produce EXPLAIN output for queries without top-level JOIN. More...

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

Public Member Functions
	Explain_table (THD const explain_thd_arg, const THD query_thd_arg, Query_block query_block_arg, TABLE const table_arg, enum join_type type_arg, AccessPath range_scan_arg, Item condition_arg, uint key_arg, ha_rows limit_arg, bool need_tmp_table_arg, bool need_sort_arg, enum_mod_type mod_type_arg, bool used_key_is_modified_arg, const char *msg)

bool	explain_modify_flags () override

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...

Private Member Functions
virtual bool	explain_tmptable_and_filesort (bool need_tmp_table_arg, bool need_sort_arg)

bool	shallow_explain () override
	Explain everything but subqueries. More...

bool	explain_ref () override

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_rows_and_filtered () override
	fill col_rows and col_filtered fields together More...

bool	explain_extra () 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...

Private Attributes
const uint	key
	cached "key" number argument More...

const ha_rows	limit
	HA_POS_ERROR or cached "limit" argument. More...

const bool	need_tmp_table
	cached need_tmp_table argument More...

const bool	need_sort
	cached need_sort argument More...

const enum_mod_type	mod_type
	Table modification type. More...

const bool	used_key_is_modified
	UPDATE command updates used key. More...

const char *	message
	cached "message" argument More...

Additional Inherited Members
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 bool	explain_id ()

virtual bool	explain_select_type ()

virtual enum_parsing_context	get_subquery_context (Query_expression *unit) const

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_table class produce EXPLAIN output for queries without top-level JOIN.

This class is a simplified version of the Explain_join class. It works in the context of queries which implementation lacks top-level JOIN object (EXPLAIN single-table UPDATE and DELETE).

Constructor & Destructor Documentation

◆ Explain_table()

anonymous_namespace{opt_explain.cc}::Explain_table::Explain_table	(	THD *const	explain_thd_arg,
		const THD *	query_thd_arg,
		Query_block *	query_block_arg,
		TABLE *const	table_arg,
		enum join_type	type_arg,
		AccessPath *	range_scan_arg,
		Item *	condition_arg,
		uint	key_arg,
		ha_rows	limit_arg,
		bool	need_tmp_table_arg,
		bool	need_sort_arg,
		enum_mod_type	mod_type_arg,
		bool	used_key_is_modified_arg,
		const char *	msg
	)

inline

Member Function Documentation

◆ can_walk_clauses()

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

inlineoverrideprivatevirtual

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.

◆ explain_extra()

bool Explain_table::explain_extra ( )

overrideprivatevirtual

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

◆ explain_join_type()

bool Explain_table::explain_join_type ( )

overrideprivatevirtual

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

◆ explain_key_and_len()

bool Explain_table::explain_key_and_len ( )

overrideprivatevirtual

fill col_key and and col_key_len fields together

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

◆ explain_modify_flags()

bool Explain_table::explain_modify_flags ( )

overridevirtual

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

◆ explain_ref()

bool Explain_table::explain_ref ( )

overrideprivatevirtual

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

◆ explain_rows_and_filtered()

bool Explain_table::explain_rows_and_filtered ( )

overrideprivatevirtual

fill col_rows and col_filtered fields together

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

◆ explain_table_name()

bool Explain_table::explain_table_name ( )

overrideprivatevirtual

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

◆ explain_tmptable_and_filesort()

bool Explain_table::explain_tmptable_and_filesort	(	bool	need_tmp_table_arg,
		bool	need_sort_arg
	)

privatevirtual

◆ shallow_explain()

bool Explain_table::shallow_explain ( )

overrideprivatevirtual

Explain everything but subqueries.

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

Member Data Documentation

◆ key

const uint anonymous_namespace{opt_explain.cc}::Explain_table::key

private

cached "key" number argument

◆ limit

const ha_rows anonymous_namespace{opt_explain.cc}::Explain_table::limit

private

HA_POS_ERROR or cached "limit" argument.

◆ message

const char* anonymous_namespace{opt_explain.cc}::Explain_table::message

private

cached "message" argument

◆ mod_type

const enum_mod_type anonymous_namespace{opt_explain.cc}::Explain_table::mod_type

private

Table modification type.

◆ need_sort

const bool anonymous_namespace{opt_explain.cc}::Explain_table::need_sort

private

cached need_sort argument

◆ need_tmp_table

const bool anonymous_namespace{opt_explain.cc}::Explain_table::need_tmp_table

private

cached need_tmp_table argument

◆ used_key_is_modified

const bool anonymous_namespace{opt_explain.cc}::Explain_table::used_key_is_modified

private

UPDATE command updates used key.

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

sql/opt_explain.cc

Public Member Functions

Private Member Functions

Private Attributes

Additional Inherited Members

Detailed Description

Constructor & Destructor Documentation

◆ Explain_table()

Member Function Documentation

◆ can_walk_clauses()

◆ explain_extra()

◆ explain_join_type()

◆ explain_key_and_len()

◆ explain_modify_flags()

◆ explain_ref()

◆ explain_rows_and_filtered()

◆ explain_table_name()

◆ explain_tmptable_and_filesort()

◆ shallow_explain()

Member Data Documentation

◆ key

◆ limit

◆ message

◆ mod_type

◆ need_sort

◆ need_tmp_table

◆ used_key_is_modified