#include "sql/join_optimizer/make_join_hypergraph.h"
#include <assert.h>
#include <stddef.h>
#include <algorithm>
#include <array>
#include <iterator>
#include <string>
#include <utility>
#include <vector>
#include "limits.h"
#include "mem_root_deque.h"
#include "my_alloc.h"
#include "my_bit.h"
#include "my_inttypes.h"
#include "my_sys.h"
#include "my_table_map.h"
#include "mysqld_error.h"
#include "sql/current_thd.h"
#include "sql/item.h"
#include "sql/item_cmpfunc.h"
#include "sql/item_func.h"
#include "sql/join_optimizer/access_path.h"
#include "sql/join_optimizer/bit_utils.h"
#include "sql/join_optimizer/common_subexpression_elimination.h"
#include "sql/join_optimizer/cost_model.h"
#include "sql/join_optimizer/estimate_selectivity.h"
#include "sql/join_optimizer/find_contained_subqueries.h"
#include "sql/join_optimizer/hypergraph.h"
#include "sql/join_optimizer/print_utils.h"
#include "sql/join_optimizer/relational_expression.h"
#include "sql/join_optimizer/subgraph_enumeration.h"
#include "sql/nested_join.h"
#include "sql/sql_class.h"
#include "sql/sql_executor.h"
#include "sql/sql_lex.h"
#include "sql/sql_optimizer.h"
#include "sql/table.h"
#include "template_utils.h"

Namespaces
namespace	anonymous_namespace{make_join_hypergraph.cc}

Enumerations
enum class	anonymous_namespace{make_join_hypergraph.cc}::AssociativeRewritesAllowed { anonymous_namespace{make_join_hypergraph.cc}::ANY , anonymous_namespace{make_join_hypergraph.cc}::RIGHT_ONLY , anonymous_namespace{make_join_hypergraph.cc}::LEFT_ONLY }

Functions
RelationalExpression *	anonymous_namespace{make_join_hypergraph.cc}::MakeRelationalExpressionFromJoinList (THD thd, const mem_root_deque< TABLE_LIST > &join_list)
	Convert the Query_block's join lists into a RelationalExpression, ie., a join tree with tables at the leaves. More...

bool	anonymous_namespace{make_join_hypergraph.cc}::EarlyNormalizeConditions (THD thd, Mem_root_array< Item > *conditions)
	Do some constant conversion/folding work needed for correctness. More...

bool	anonymous_namespace{make_join_hypergraph.cc}::IsMultipleEquals (Item *cond)

Item_func_eq *	anonymous_namespace{make_join_hypergraph.cc}::MakeEqItem (Item a, Item b, Item_equal *source_multiple_equality)

void	anonymous_namespace{make_join_hypergraph.cc}::ExpandSameTableFromMultipleEquals (Item_equal equal, table_map tables_in_subtree, List< Item > eq_items)
	For a multiple equality, split out any conditions that refer to the same table, without touching the multi-equality; e.g. More...

Item *	anonymous_namespace{make_join_hypergraph.cc}::EarlyExpandMultipleEquals (Item *condition, table_map tables_in_subtree)
	Expand multiple equalities that can (and should) be expanded before join pushdown. More...

RelationalExpression *	anonymous_namespace{make_join_hypergraph.cc}::MakeRelationalExpression (THD thd, const TABLE_LIST tl)

void	anonymous_namespace{make_join_hypergraph.cc}::ComputeCompanionSets (RelationalExpression expr, int current_set, int num_companion_sets, int table_num_to_companion_set[MAX_TABLES])

void	anonymous_namespace{make_join_hypergraph.cc}::CreateInnerJoinFromChildList (Mem_root_array< RelationalExpression * > children, RelationalExpression *expr)
	Convert a multi-join into a simple inner join. More...

void	anonymous_namespace{make_join_hypergraph.cc}::FlattenInnerJoins (RelationalExpression *expr)
	Find all inner joins under “expr” without a join condition, and convert them to a flattened join (MULTI_INNER_JOIN). More...

void	anonymous_namespace{make_join_hypergraph.cc}::UnflattenInnerJoins (RelationalExpression *expr)
	The opposite of FlattenInnerJoins(); converts all flattened joins to a series of (right-deep) binary joins. More...

RelationalExpression *	anonymous_namespace{make_join_hypergraph.cc}::PartiallyUnflattenJoinForCondition (table_map used_tables, RelationalExpression *expr)
	For the given flattened join (multi-join), pull out (only) the parts we need to push the given condition, and make a binary join for it. More...

string	anonymous_namespace{make_join_hypergraph.cc}::PrintRelationalExpression (RelationalExpression *expr, int level)

bool	anonymous_namespace{make_join_hypergraph.cc}::IsNullRejecting (const RelationalExpression &expr, table_map tables)

bool	anonymous_namespace{make_join_hypergraph.cc}::IsInnerJoin (RelationalExpression::Type type)

bool	anonymous_namespace{make_join_hypergraph.cc}::OperatorsAreAssociative (const RelationalExpression &a, const RelationalExpression &b)

bool	anonymous_namespace{make_join_hypergraph.cc}::OperatorsAreLeftAsscom (const RelationalExpression &a, const RelationalExpression &b)

bool	anonymous_namespace{make_join_hypergraph.cc}::OperatorsAreRightAsscom (const RelationalExpression &a, const RelationalExpression &b)

table_map	anonymous_namespace{make_join_hypergraph.cc}::UsedTablesForCondition (const RelationalExpression &expr)
	Find a bitmap of used tables for all conditions on <expr>. More...

table_map	anonymous_namespace{make_join_hypergraph.cc}::CertainlyUsedTablesForCondition (const RelationalExpression &expr)
	Like UsedTablesForCondition(), but multiple equalities set no bits unless they're certain, i.e., cannot be avoided no matter how we break up the multiple equality. More...

int	anonymous_namespace{make_join_hypergraph.cc}::CompanionSetUsedByCondition (table_map tables, const int table_num_to_companion_set[MAX_TABLES])
	For a given set of tables, find the companion set they are part of (see RelationalExpression::companion_set for an explanation of companion sets). More...

bool	anonymous_namespace{make_join_hypergraph.cc}::IsCandidateForCycle (RelationalExpression expr, Item cond, const int table_num_to_companion_set[MAX_TABLES])
	Check whether we are allowed to make an extra join edge with the given condition, instead of pushing the condition onto the given point in the join tree (which we have presumably found out that we don't want). More...

bool	anonymous_namespace{make_join_hypergraph.cc}::ComesFromMultipleEquality (Item item, Item_equal equal)

int	anonymous_namespace{make_join_hypergraph.cc}::FindSourceMultipleEquality (Item item, const Mem_root_array< Item_equal > &equals)

bool	anonymous_namespace{make_join_hypergraph.cc}::MultipleEqualityAlreadyExistsOnJoin (Item_equal *equal, const RelationalExpression &expr)

bool	anonymous_namespace{make_join_hypergraph.cc}::AlreadyExistsOnJoin (Item *cond, const RelationalExpression &expr)

bool	anonymous_namespace{make_join_hypergraph.cc}::IsBadJoinForCondition (const RelationalExpression &expr, Item *cond)
	Returns whether adding “cond” to the given join would unduly enlarge the number of tables it references, or create a degenerate join. More...

void	anonymous_namespace{make_join_hypergraph.cc}::RotateRight (RelationalExpression *op)
	Applies the following rewrite on <op>: More...

void	anonymous_namespace{make_join_hypergraph.cc}::RotateLeft (RelationalExpression *op)
	Opposite of RotateRight; that is: More...

Item_func_eq *	anonymous_namespace{make_join_hypergraph.cc}::ConcretizeMultipleEquals (Item_equal *cond, const RelationalExpression &expr)
	From “cond”, create exactly one simple equality that will connect the left and right sides of “expr”. More...

template<class T >
static void	anonymous_namespace{make_join_hypergraph.cc}::FullyConcretizeMultipleEquals (Item_equal cond, table_map allowed_tables, T result)
	From “cond”, create exactly as many simple equalities that are needed to connect all tables in “allowed_tables”. More...

Item *	anonymous_namespace{make_join_hypergraph.cc}::CanonicalizeCondition (Item *condition, table_map allowed_tables)
	Finalize a condition (join condition or WHERE predicate); resolve any remaining multiple equalities, and add casts to comparisons where needed. More...

bool	anonymous_namespace{make_join_hypergraph.cc}::CanonicalizeConditions (THD thd, table_map tables_in_subtree, Mem_root_array< Item > *conditions)

bool	anonymous_namespace{make_join_hypergraph.cc}::AddJoinConditionPossiblyWithRewrite (RelationalExpression expr, Item cond, AssociativeRewritesAllowed allowed, bool used_commutativity, bool need_flatten, string trace)
	Add “cond” as a join condition to “expr”, but if it would enlarge the set of referenced tables, try to rewrite the join tree using associativity (either left or right) to be able to put the condition on a more favorable node. More...

void	anonymous_namespace{make_join_hypergraph.cc}::PushDownCondition (Item cond, RelationalExpression expr, bool is_join_condition_for_expr, const int table_num_to_companion_set[MAX_TABLES], Mem_root_array< Item * > table_filters, Mem_root_array< Item > cycle_inducing_edges, Mem_root_array< Item > remaining_parts, string trace)
	Try to push down the condition “cond” down in the join tree given by “expr”, as far as possible. More...

void	anonymous_namespace{make_join_hypergraph.cc}::PushDownToSargableCondition (Item cond, RelationalExpression expr, bool is_join_condition_for_expr)
	Try to push down conditions (like PushDownCondition()), but with the intent of pushing join conditions down to sargable conditions on tables. More...

Mem_root_array< Item * >	anonymous_namespace{make_join_hypergraph.cc}::PushDownAsMuchAsPossible (THD thd, Mem_root_array< Item > conditions, RelationalExpression expr, bool is_join_condition_for_expr, const int table_num_to_companion_set[MAX_TABLES], Mem_root_array< Item > table_filters, Mem_root_array< Item > cycle_inducing_edges, string trace)
	Push down as many of the conditions in “conditions” as we can, into the join tree under “expr”. More...

void	anonymous_namespace{make_join_hypergraph.cc}::PushDownJoinConditions (THD thd, RelationalExpression expr, const int table_num_to_companion_set[MAX_TABLES], Mem_root_array< Item * > table_filters, Mem_root_array< Item > cycle_inducing_edges, string trace)
	For each condition posted as a join condition on “expr”, try to push all of them further down the tree, as far as we can; then recurse to the child nodes, if any. More...

void	anonymous_namespace{make_join_hypergraph.cc}::PushDownJoinConditionsForSargable (THD thd, RelationalExpression expr)
	Similar to PushDownJoinConditions(), but for push of sargable conditions (see PushDownJoinConditionsForSargable()). More...

void	anonymous_namespace{make_join_hypergraph.cc}::LateConcretizeMultipleEqualities (THD thd, RelationalExpression expr)
	Do a final pass of unexpanded (and non-degenerate) multiple equalities on join conditions, deciding on what equalities to concretize them into right before pushing join conditions to sargable predicates. More...

table_map	anonymous_namespace{make_join_hypergraph.cc}::FindNullGuaranteedTables (const RelationalExpression *expr)

void	anonymous_namespace{make_join_hypergraph.cc}::ClearImpossibleJoinConditions (RelationalExpression *expr)

bool	anonymous_namespace{make_join_hypergraph.cc}::ShouldCompleteMeshForCondition (Item_equal *item_equal, const int table_num_to_companion_set[MAX_TABLES])
	Find out whether we should create mesh edges (all-to-all) for this multiple equality. More...

void	anonymous_namespace{make_join_hypergraph.cc}::ExtractCycleMultipleEqualities (const Mem_root_array< Item * > &conditions, const int table_num_to_companion_set[MAX_TABLES], Mem_root_array< Item_equal * > *multiple_equalities)

void	anonymous_namespace{make_join_hypergraph.cc}::ExtractCycleMultipleEqualitiesFromJoinConditions (const RelationalExpression expr, const int table_num_to_companion_set[MAX_TABLES], Mem_root_array< Item_equal > *multiple_equalities)

bool	anonymous_namespace{make_join_hypergraph.cc}::CanonicalizeJoinConditions (THD thd, RelationalExpression expr)
	Find constant expressions in join conditions, and add caches around them. More...

void	anonymous_namespace{make_join_hypergraph.cc}::MakeHashJoinConditions (THD thd, RelationalExpression expr)
	For all join conditions on “expr”, go through and figure out which ones are equijoin conditions, ie., suitable for hash join. More...

void	anonymous_namespace{make_join_hypergraph.cc}::FindConditionsUsedTables (THD thd, RelationalExpression expr)

void	anonymous_namespace{make_join_hypergraph.cc}::CSEConditions (THD thd, Mem_root_array< Item > *conditions)
	Run simple CSE on all conditions (see CommonSubexpressionElimination()). More...

string	anonymous_namespace{make_join_hypergraph.cc}::PrintJoinList (const mem_root_deque< TABLE_LIST * > &join_list, int level)

table_map	anonymous_namespace{make_join_hypergraph.cc}::FindTESForCondition (table_map used_tables, const RelationalExpression *expr)
	For a condition with the SES (Syntactic Eligibility Set) “used_tables”, find all relations in or under “expr” that are part of the condition's TES (Total Eligibility Set). More...

string	PrintDottyHypergraph (const JoinHypergraph &graph)
	For the given hypergraph, make a textual representation in the form of a dotty graph. More...

NodeMap	anonymous_namespace{make_join_hypergraph.cc}::IntersectIfNotDegenerate (NodeMap used_nodes, NodeMap available_nodes)

NodeMap	anonymous_namespace{make_join_hypergraph.cc}::AbsorbConflictRulesIntoTES (NodeMap total_eligibility_set, Mem_root_array< ConflictRule > *conflict_rules)
	When we have the conflict rules, we want to fold them into the hyperedge we are about to create. More...

Hyperedge	anonymous_namespace{make_join_hypergraph.cc}::FindHyperedgeAndJoinConflicts (THD thd, NodeMap used_nodes, RelationalExpression expr)
	For the join operator in “expr”, build a hyperedge that encapsulates its reordering conditions as completely as possible. More...

size_t	anonymous_namespace{make_join_hypergraph.cc}::EstimateRowWidthForJoin (const JoinHypergraph &graph, const RelationalExpression *expr)

int	anonymous_namespace{make_join_hypergraph.cc}::AddPredicate (THD thd, Item condition, bool was_join_condition, int source_multiple_equality_idx, const RelationalExpression root, JoinHypergraph graph, string *trace)
	Add the given predicate to the list of WHERE predicates, doing some bookkeeping that such predicates need. More...

bool	anonymous_namespace{make_join_hypergraph.cc}::AreNodesConnected (const Hypergraph &graph, int source, int destination, int forbidden_edge_idx, NodeMap *seen_nodes)
	Return whether we can find a path from “source” to “destination”, without using forbidden_edge_idx. More...

bool	anonymous_namespace{make_join_hypergraph.cc}::IsPartOfCycle (const JoinHypergraph *graph, int edge_idx)
	Returns whether the given edge is part of a graph cycle; if so, its join condition might not actually get evaluated as part of the regular structure, and we need to take special precautions (make backup WHERE conditions for them). More...

void	anonymous_namespace{make_join_hypergraph.cc}::AddCycleEdges (THD thd, const Mem_root_array< Item > &cycle_inducing_edges, JoinHypergraph graph, string trace)
	For each of the given join conditions, add a cycle-inducing edge to the hypergraph. More...

void	anonymous_namespace{make_join_hypergraph.cc}::PromoteCycleJoinPredicates (THD thd, const RelationalExpression root, const Mem_root_array< Item_equal * > &multiple_equalities, JoinHypergraph graph, string trace)
	Promote join predicates that became part of (newly-formed) cycles to WHERE predicates. More...

void	MakeJoinGraphFromRelationalExpression (THD thd, RelationalExpression expr, string trace, JoinHypergraph graph)
	Convert a join rooted at “expr” into a join hypergraph that encapsulates the constraints given by the relational expressions (e.g. More...

NodeMap	GetNodeMapFromTableMap (table_map map, const array< int, MAX_TABLES > &table_num_to_node_num)

bool	anonymous_namespace{make_join_hypergraph.cc}::ExistsEdgeBetween (const JoinHypergraph graph, int left_node_idx, int right_node_idx, int out_edge_idx)

void	anonymous_namespace{make_join_hypergraph.cc}::AddMultipleEqualityPredicate (THD thd, Item_equal item_equal, Item_field left_field, int left_table_idx, Item_field right_field, int right_table_idx, double selectivity, JoinHypergraph *graph)

void	anonymous_namespace{make_join_hypergraph.cc}::CompleteFullMeshForMultipleEqualities (THD thd, const Mem_root_array< Item_equal > &multiple_equalities, JoinHypergraph graph, string trace)
	For each relevant multiple equality, add edges so that there are direct connections between all the involved tables (full mesh). More...

bool	MakeJoinHypergraph (THD thd, string trace, JoinHypergraph *graph)

Function Documentation

◆ GetNodeMapFromTableMap()

NodeMap GetNodeMapFromTableMap	(	table_map	map,
		const array< int, MAX_TABLES > &	table_num_to_node_num
	)

◆ MakeJoinGraphFromRelationalExpression()

void MakeJoinGraphFromRelationalExpression	(	THD *	thd,
		RelationalExpression *	expr,
		string *	trace,
		JoinHypergraph *	graph
	)

Convert a join rooted at “expr” into a join hypergraph that encapsulates the constraints given by the relational expressions (e.g.

inner joins are more freely reorderable than outer joins).

The function in itself only does some bookkeeping around node bitmaps, and then defers the actual conflict detection logic to FindHyperedgeAndJoinConflicts().

◆ MakeJoinHypergraph()

bool MakeJoinHypergraph	(	THD *	thd,
		string *	trace,
		JoinHypergraph *	graph
	)

◆ PrintDottyHypergraph()

string PrintDottyHypergraph ( const JoinHypergraph & graph )

For the given hypergraph, make a textual representation in the form of a dotty graph.

You can save this to a file and then use Graphviz to render this it a graphical representation of the hypergraph for easier debugging, e.g. like this:

dot -Tps graph.dot > graph.ps display graph.ps

Namespaces

Enumerations

Functions

Function Documentation

◆ GetNodeMapFromTableMap()

◆ MakeJoinGraphFromRelationalExpression()

◆ MakeJoinHypergraph()

◆ PrintDottyHypergraph()