Explain_union_result class outputs EXPLAIN row for UNION. More...

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

Public Member Functions
	Explain_setop_result (THD explain_thd_arg, const THD query_thd_arg, Query_block query_block_arg, Query_term qt, enum_parsing_context ctx)

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	explain_id () override

bool	explain_table_name () override

bool	explain_join_type () override

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...

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)

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

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_select_type ()

virtual bool	explain_partitions ()

virtual bool	explain_possible_keys ()

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

virtual bool	explain_ref ()

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

virtual bool	explain_modify_flags ()

virtual enum_parsing_context	get_subquery_context (Query_expression *unit) const

Protected Attributes
Query_term_set_op *	m_query_term

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_union_result class outputs EXPLAIN row for UNION.

Constructor & Destructor Documentation

◆ Explain_setop_result()

anonymous_namespace{opt_explain.cc}::Explain_setop_result::Explain_setop_result	(	THD *	explain_thd_arg,
		const THD *	query_thd_arg,
		Query_block *	query_block_arg,
		Query_term *	qt,
		enum_parsing_context	ctx
	)

inline

Member Function Documentation

◆ can_walk_clauses()

bool anonymous_namespace{opt_explain.cc}::Explain_setop_result::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.