Query optimization plan node. More...

#include <sql_select.h>

Inheritance diagram for JOIN_TAB:

Public Member Functions
	JOIN_TAB ()

void	set_table (TABLE *t)

void	init_join_cond_ref (Table_ref *tl)
	Sets the pointer to the join condition of Table_ref. More...

Item *	join_cond () const

void	set_join_cond (Item *cond)
	Sets join condition. More...

void	set_condition (Item *to)
	Set the combined condition for a table (may be performed several times) More...

uint	use_join_cache () const

void	set_use_join_cache (uint u)

Key_use *	keyuse () const

void	set_keyuse (Key_use *k)

void	cleanup ()
	Clean up associated table after query execution, including resources. More...

uint	get_sj_strategy () const

Public Member Functions inherited from QEP_shared_owner
	QEP_shared_owner ()

void	share_qs (QEP_shared_owner *other)
	Instructs to share the QEP_shared with another owner. More...

void	set_qs (QEP_shared *q)

JOIN *	join () const

void	set_join (JOIN *j)

plan_idx	idx () const

void	set_idx (plan_idx i)

qep_tab_map	idx_map () const

TABLE *	table () const

POSITION *	position () const

void	set_position (POSITION *p)

Semijoin_mat_exec *	sj_mat_exec () const

void	set_sj_mat_exec (Semijoin_mat_exec *s)

plan_idx	first_sj_inner () const

plan_idx	last_sj_inner () const

plan_idx	first_inner () const

plan_idx	last_inner () const

plan_idx	first_upper () const

void	set_first_inner (plan_idx i)

void	set_last_inner (plan_idx i)

void	set_first_sj_inner (plan_idx i)

void	set_last_sj_inner (plan_idx i)

void	set_first_upper (plan_idx i)

Index_lookup &	ref () const

uint	index () const

void	set_index (uint i)

enum join_type	type () const

void	set_type (enum join_type t)

Item *	condition () const

void	set_condition (Item *to)

bool	condition_is_pushed_to_sort () const

void	mark_condition_as_pushed_to_sort ()

Key_map &	keys () const

ha_rows	records () const

void	set_records (ha_rows r)

AccessPath *	range_scan () const

void	set_range_scan (AccessPath *q)

table_map	prefix_tables () const

table_map	added_tables () const

Item_func_match *	ft_func () const

void	set_ft_func (Item_func_match *f)

void	set_prefix_tables (table_map prefix_tables, table_map prev_tables)

void	add_prefix_tables (table_map tables)

bool	is_single_inner_of_semi_join () const

bool	is_inner_table_of_outer_join () const

bool	is_first_inner_for_outer_join () const

bool	is_single_inner_for_outer_join () const

bool	has_guarded_conds () const

bool	and_with_condition (Item *tmp_cond)
	Extend join_tab->cond by AND'ing add_cond to it. More...

void	set_skip_records_in_range (bool skip_records_in_range)

bool	skip_records_in_range () const

void	qs_cleanup ()

Public Attributes
Table_ref *	table_ref
	points to table reference More...

COND_EQUAL *	cond_equal
	multiple equalities for the on expression More...

double	worst_seeks
	The maximum value for the cost of seek operations for key lookup during ref access. More...

Key_map	const_keys
	Keys with constant part. More...

Key_map	checked_keys
	Keys checked. More...

Key_map	skip_scan_keys
	Keys which can be used for skip scan access. More...

Key_map	needed_reg

Key_map	quick_order_tested
	Used to avoid repeated range analysis for the same key in test_if_skip_sort_order(). More...

ha_rows	found_records

double	read_time

table_map	dependent
	The set of tables that this table depends on. More...

table_map	key_dependent
	The set of tables that are referenced by key from this table. More...

uint	used_fieldlength

enum quick_type	use_quick

uint	m_use_join_cache
	Join buffering strategy. More...

Table_ref *	emb_sj_nest

nested_join_map	embedding_map

uint	join_cache_flags
	Flags from SE's MRR implementation, to be used by JOIN_CACHE. More...

bool	reversed_access
	true <=> AM will scan backward More...

Private Member Functions
	JOIN_TAB (const JOIN_TAB &)

JOIN_TAB &	operator= (const JOIN_TAB &)

Private Attributes
Key_use *	m_keyuse
	pointer to first used key More...

Item **	m_join_cond_ref
	Pointer to the associated join condition: More...

Additional Inherited Members
Protected Attributes inherited from QEP_shared_owner
QEP_shared *	m_qs

Detailed Description

Query optimization plan node.

Specifies:

a table access operation on the table specified by this node, and
a join between the result of the set of previous plan nodes and this plan node.

Constructor & Destructor Documentation

◆ JOIN_TAB() [1/2]

JOIN_TAB::JOIN_TAB ( )

inline

◆ JOIN_TAB() [2/2]

JOIN_TAB::JOIN_TAB ( const JOIN_TAB & )

private

Member Function Documentation

◆ join_cond()

Item * JOIN_TAB::join_cond ( ) const

inline

Returns: join condition

◆ keyuse()

Key_use * JOIN_TAB::keyuse ( ) const

inline

◆ operator=()

JOIN_TAB & JOIN_TAB::operator= ( const JOIN_TAB & )

private

◆ set_condition()

void JOIN_TAB::set_condition ( Item * to )

inline

Set the combined condition for a table (may be performed several times)

◆ set_join_cond()

void JOIN_TAB::set_join_cond ( Item * cond )

inline

Sets join condition.

Note: this also changes Table_ref::m_join_cond.

◆ set_keyuse()

void JOIN_TAB::set_keyuse ( Key_use * k )

inline

◆ set_use_join_cache()

void JOIN_TAB::set_use_join_cache ( uint u )

inline

◆ use_join_cache()

uint JOIN_TAB::use_join_cache ( ) const

inline

Member Data Documentation

◆ checked_keys

Key_map JOIN_TAB::checked_keys

Keys checked.

◆ cond_equal

COND_EQUAL* JOIN_TAB::cond_equal

multiple equalities for the on expression

◆ const_keys

Key_map JOIN_TAB::const_keys

Keys with constant part.

Subset of keys.

◆ dependent

table_map JOIN_TAB::dependent

The set of tables that this table depends on.

Used for outer join and straight join dependencies.

◆ emb_sj_nest

Table_ref* JOIN_TAB::emb_sj_nest

◆ embedding_map

nested_join_map JOIN_TAB::embedding_map

◆ found_records

ha_rows JOIN_TAB::found_records

◆ join_cache_flags

uint JOIN_TAB::join_cache_flags

Flags from SE's MRR implementation, to be used by JOIN_CACHE.

◆ key_dependent

table_map JOIN_TAB::key_dependent

The set of tables that are referenced by key from this table.

◆ m_join_cond_ref

Item** JOIN_TAB::m_join_cond_ref

private

Pointer to the associated join condition:

if this is a table with position==NULL (e.g. internal sort/group temporary table), pointer is NULL
otherwise, pointer is the address of some Table_ref::m_join_cond. Thus, the pointee is the same as Table_ref::m_join_cond (changing one changes the other; thus, optimizations made on the second are reflected in Query_block::print_table_array() which uses the first one).

◆ m_keyuse

Key_use* JOIN_TAB::m_keyuse

private

pointer to first used key

◆ m_use_join_cache

uint JOIN_TAB::m_use_join_cache

Join buffering strategy.

After optimization it contains chosen join buffering strategy (if any).

◆ needed_reg

Key_map JOIN_TAB::needed_reg

◆ quick_order_tested

Key_map JOIN_TAB::quick_order_tested

Used to avoid repeated range analysis for the same key in test_if_skip_sort_order().

This would otherwise happen if the best range access plan found for a key is turned down. quick_order_tested is cleared every time the select condition for this JOIN_TAB changes since a new condition may give another plan and cost from range analysis.

◆ read_time

double JOIN_TAB::read_time

◆ reversed_access

bool JOIN_TAB::reversed_access

true <=> AM will scan backward

◆ skip_scan_keys

Key_map JOIN_TAB::skip_scan_keys

Keys which can be used for skip scan access.

We store it separately from tab->const_keys & join_tab->keys() to avoid unnecessary printing of the prossible keys in EXPLAIN output as some of these keys can be marked not usable for skip scan later. More strict check for prossible keys is performed in get_best_skip_scan() function.

◆ table_ref

Table_ref* JOIN_TAB::table_ref

points to table reference

◆ use_quick

enum quick_type JOIN_TAB::use_quick

◆ used_fieldlength

uint JOIN_TAB::used_fieldlength

◆ worst_seeks

double JOIN_TAB::worst_seeks

The maximum value for the cost of seek operations for key lookup during ref access.

The cost model for ref access assumes every key lookup will cause reading a block from disk. With many key lookups into the same table, most of the blocks will soon be in a memory buffer. As a consequence, there will in most cases be an upper limit on the number of actual disk accesses the ref access will cause. This variable is used for storing a maximum cost estimate for the disk accesses for ref access. It is used for limiting the cost estimate for ref access to a more realistic value than assuming every key lookup causes a random disk access. Without having this upper limit for the cost of ref access, table scan would be more likely to be chosen for cases where ref access performs better.

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

Public Member Functions

Public Attributes

Private Member Functions

Private Attributes

Additional Inherited Members

Detailed Description

Constructor & Destructor Documentation

◆ JOIN_TAB() [1/2]

◆ JOIN_TAB() [2/2]

Member Function Documentation

◆ join_cond()

◆ keyuse()

◆ operator=()

◆ set_condition()

◆ set_join_cond()

◆ set_keyuse()

◆ set_use_join_cache()

◆ use_join_cache()

Member Data Documentation

◆ checked_keys

◆ cond_equal

◆ const_keys

◆ dependent

◆ emb_sj_nest

◆ embedding_map

◆ found_records

◆ join_cache_flags

◆ key_dependent

◆ m_join_cond_ref

◆ m_keyuse

◆ m_use_join_cache

◆ needed_reg

◆ quick_order_tested

◆ read_time

◆ reversed_access

◆ skip_scan_keys

◆ table_ref

◆ use_quick

◆ used_fieldlength

◆ worst_seeks