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-rw-r--r--mysql-test/r/subselect4.result46
-rw-r--r--mysql-test/r/subselect_mat_cost_bugs.result70
-rw-r--r--mysql-test/t/subselect4.test42
-rw-r--r--mysql-test/t/subselect_mat_cost_bugs.test83
-rw-r--r--sql/item_cmpfunc.cc5
-rw-r--r--sql/item_subselect.h2
-rw-r--r--sql/opt_subselect.cc70
-rw-r--r--sql/sql_lex.cc2
-rw-r--r--sql/sql_list.h2
-rw-r--r--sql/sql_select.cc34
-rw-r--r--sql/sql_select.h5
11 files changed, 185 insertions, 176 deletions
diff --git a/mysql-test/r/subselect4.result b/mysql-test/r/subselect4.result
index e22a0f04a4d..a8102486f6b 100644
--- a/mysql-test/r/subselect4.result
+++ b/mysql-test/r/subselect4.result
@@ -1655,52 +1655,6 @@ f1b f2b f3b
set @@optimizer_switch=@save_optimizer_switch;
drop table t0,t1,t2;
#
-# LP BUG#718593 Crash in substitute_for_best_equal_field -> eliminate_item_equal ->
-# Item_field::find_item_equal -> Item_equal::contains
-#
-set @save_optimizer_switch=@@optimizer_switch;
-SET @@optimizer_switch = 'semijoin=off';
-CREATE TABLE t1 ( f3 int(11), f10 varchar(1), f11 varchar(1)) ;
-INSERT IGNORE INTO t1 VALUES (6,'f','f'),(2,'d','d');
-CREATE TABLE t2 ( f12 int(11), f13 int(11)) ;
-insert into t2 values (1,2), (3,4);
-EXPLAIN
-SELECT * FROM t2
-WHERE ( f12 ) IN (
-SELECT alias2.f3
-FROM t1 AS alias1 JOIN t1 AS alias2 ON alias2.f10 = alias1.f11
-WHERE alias1.f11 OR alias1.f3 = 50 AND alias1.f10
-);
-id select_type table type possible_keys key key_len ref rows Extra
-1 PRIMARY t2 ALL NULL NULL NULL NULL 2 Using where
-2 DEPENDENT SUBQUERY alias1 ALL NULL NULL NULL NULL 2 Using where
-2 DEPENDENT SUBQUERY alias2 ALL NULL NULL NULL NULL 2 Using where; Using join buffer (flat, BNL join)
-SELECT * FROM t2
-WHERE ( f12 ) IN (
-SELECT alias2.f3
-FROM t1 AS alias1 JOIN t1 AS alias2 ON alias2.f10 = alias1.f11
-WHERE alias1.f11 OR alias1.f3 = 50 AND alias1.f10
-);
-f12 f13
-EXPLAIN
-SELECT * FROM t2
-WHERE ( f12 ) IN (
-SELECT alias2.f3
-FROM t1 AS alias1, t1 AS alias2
-WHERE (alias2.f10 = alias1.f11) AND (alias1.f11 OR alias1.f3 = 50 AND alias1.f10));
-id select_type table type possible_keys key key_len ref rows Extra
-1 PRIMARY t2 ALL NULL NULL NULL NULL 2 Using where
-2 DEPENDENT SUBQUERY alias1 ALL NULL NULL NULL NULL 2 Using where
-2 DEPENDENT SUBQUERY alias2 ALL NULL NULL NULL NULL 2 Using where; Using join buffer (flat, BNL join)
-SELECT * FROM t2
-WHERE ( f12 ) IN (
-SELECT alias2.f3
-FROM t1 AS alias1, t1 AS alias2
-WHERE (alias2.f10 = alias1.f11) AND (alias1.f11 OR alias1.f3 = 50 AND alias1.f10));
-f12 f13
-set @@optimizer_switch=@save_optimizer_switch;
-drop table t1, t2;
-#
# LP BUG#715759 Wrong result with in_to_exists=on in maria-5.3-mwl89
#
set @save_optimizer_switch=@@optimizer_switch;
diff --git a/mysql-test/r/subselect_mat_cost_bugs.result b/mysql-test/r/subselect_mat_cost_bugs.result
index cd0a6c716bb..18f2513a76d 100644
--- a/mysql-test/r/subselect_mat_cost_bugs.result
+++ b/mysql-test/r/subselect_mat_cost_bugs.result
@@ -229,6 +229,72 @@ FROM t1 STRAIGHT_JOIN t2 ON t2.f3 = t1.f3
WHERE t2.f3 = 'c');
f2 f3
drop table t1,t2,t3;
+#
+# LP BUG#718593 Crash in substitute_for_best_equal_field -> eliminate_item_equal ->
+# Item_field::find_item_equal -> Item_equal::contains
#
-# LP BUG#718593 Crash in substitute_for_best_equal_field ->
-# eliminate_item_equal -> Item_field::find_item_equal -> Item_equal::contains
+set @save_optimizer_switch=@@optimizer_switch;
+SET @@optimizer_switch = 'semijoin=off';
+CREATE TABLE t1 ( f3 int(11), f10 varchar(1), f11 varchar(1)) ;
+INSERT IGNORE INTO t1 VALUES (6,'f','f'),(2,'d','d');
+CREATE TABLE t2 ( f12 int(11), f13 int(11)) ;
+insert into t2 values (1,2), (3,4);
+EXPLAIN
+SELECT * FROM t2
+WHERE ( f12 ) IN (
+SELECT alias2.f3
+FROM t1 AS alias1 JOIN t1 AS alias2 ON alias2.f10 = alias1.f11
+WHERE alias1.f11 OR alias1.f3 = 50 AND alias1.f10
+);
+id select_type table type possible_keys key key_len ref rows Extra
+1 PRIMARY t2 ALL NULL NULL NULL NULL 2 Using where
+2 SUBQUERY alias1 ALL NULL NULL NULL NULL 2 Using where
+2 SUBQUERY alias2 ALL NULL NULL NULL NULL 2 Using where; Using join buffer (flat, BNL join)
+SELECT * FROM t2
+WHERE ( f12 ) IN (
+SELECT alias2.f3
+FROM t1 AS alias1 JOIN t1 AS alias2 ON alias2.f10 = alias1.f11
+WHERE alias1.f11 OR alias1.f3 = 50 AND alias1.f10
+);
+f12 f13
+EXPLAIN
+SELECT * FROM t2
+WHERE ( f12 ) IN (
+SELECT alias2.f3
+FROM t1 AS alias1, t1 AS alias2
+WHERE (alias2.f10 = alias1.f11) AND (alias1.f11 OR alias1.f3 = 50 AND alias1.f10));
+id select_type table type possible_keys key key_len ref rows Extra
+1 PRIMARY t2 ALL NULL NULL NULL NULL 2 Using where
+2 SUBQUERY alias1 ALL NULL NULL NULL NULL 2 Using where
+2 SUBQUERY alias2 ALL NULL NULL NULL NULL 2 Using where; Using join buffer (flat, BNL join)
+SELECT * FROM t2
+WHERE ( f12 ) IN (
+SELECT alias2.f3
+FROM t1 AS alias1, t1 AS alias2
+WHERE (alias2.f10 = alias1.f11) AND (alias1.f11 OR alias1.f3 = 50 AND alias1.f10));
+f12 f13
+set @@optimizer_switch=@save_optimizer_switch;
+drop table t1, t2;
+#
+# MWL#89: test introduced after Sergey Petrunia's review - test that
+# keyparts wihtout index prefix are used with the IN-EXISTS strategy.
+#
+create table t1 (c1 int);
+insert into t1 values (1), (2), (3);
+create table t2 (kp1 int, kp2 int, c2 int, filler char(100));
+insert into t2 values (0,0,0,'filler'),(0,1,1,'filler'),(0,2,2,'filler'),(0,3,3,'filler');
+create index key1 on t2 (kp1, kp2);
+create index key2 on t2 (kp1);
+create index key3 on t2 (kp2);
+set session optimizer_switch='default';
+analyze table t2;
+Table Op Msg_type Msg_text
+test.t2 analyze status OK
+explain
+select c1 from t1 where c1 in (select kp1 from t2 where kp2 = 10 and c2 = 4) or c1 > 7;
+id select_type table type possible_keys key key_len ref rows Extra
+1 PRIMARY t1 ALL NULL NULL NULL NULL 3 Using where
+2 DEPENDENT SUBQUERY t2 index_subquery key1,key2,key3 key1 10 func,const 1 Using where
+select c1 from t1 where c1 in (select kp1 from t2 where kp2 = 10 and c2 = 4) or c1 > 7;
+c1
+drop table t1, t2;
diff --git a/mysql-test/t/subselect4.test b/mysql-test/t/subselect4.test
index 33a6329401f..768f37c1b6c 100644
--- a/mysql-test/t/subselect4.test
+++ b/mysql-test/t/subselect4.test
@@ -1328,48 +1328,6 @@ set @@optimizer_switch=@save_optimizer_switch;
drop table t0,t1,t2;
---echo #
---echo # LP BUG#718593 Crash in substitute_for_best_equal_field -> eliminate_item_equal ->
---echo # Item_field::find_item_equal -> Item_equal::contains
---echo #
-
-set @save_optimizer_switch=@@optimizer_switch;
-SET @@optimizer_switch = 'semijoin=off';
-
-CREATE TABLE t1 ( f3 int(11), f10 varchar(1), f11 varchar(1)) ;
-INSERT IGNORE INTO t1 VALUES (6,'f','f'),(2,'d','d');
-
-CREATE TABLE t2 ( f12 int(11), f13 int(11)) ;
-insert into t2 values (1,2), (3,4);
-
-EXPLAIN
-SELECT * FROM t2
-WHERE ( f12 ) IN (
- SELECT alias2.f3
- FROM t1 AS alias1 JOIN t1 AS alias2 ON alias2.f10 = alias1.f11
- WHERE alias1.f11 OR alias1.f3 = 50 AND alias1.f10
-);
-SELECT * FROM t2
-WHERE ( f12 ) IN (
- SELECT alias2.f3
- FROM t1 AS alias1 JOIN t1 AS alias2 ON alias2.f10 = alias1.f11
- WHERE alias1.f11 OR alias1.f3 = 50 AND alias1.f10
-);
-
-EXPLAIN
-SELECT * FROM t2
-WHERE ( f12 ) IN (
- SELECT alias2.f3
- FROM t1 AS alias1, t1 AS alias2
- WHERE (alias2.f10 = alias1.f11) AND (alias1.f11 OR alias1.f3 = 50 AND alias1.f10));
-SELECT * FROM t2
-WHERE ( f12 ) IN (
- SELECT alias2.f3
- FROM t1 AS alias1, t1 AS alias2
- WHERE (alias2.f10 = alias1.f11) AND (alias1.f11 OR alias1.f3 = 50 AND alias1.f10));
-
-set @@optimizer_switch=@save_optimizer_switch;
-drop table t1, t2;
--echo #
--echo # LP BUG#715759 Wrong result with in_to_exists=on in maria-5.3-mwl89
diff --git a/mysql-test/t/subselect_mat_cost_bugs.test b/mysql-test/t/subselect_mat_cost_bugs.test
index bc052ea04b1..0240c9203b3 100644
--- a/mysql-test/t/subselect_mat_cost_bugs.test
+++ b/mysql-test/t/subselect_mat_cost_bugs.test
@@ -258,54 +258,71 @@ WHERE ( f2 ) IN (SELECT t1.f1
drop table t1,t2,t3;
+--echo #
+--echo # LP BUG#718593 Crash in substitute_for_best_equal_field -> eliminate_item_equal ->
+--echo # Item_field::find_item_equal -> Item_equal::contains
--echo #
---echo # LP BUG#718593 Crash in substitute_for_best_equal_field ->
---echo # eliminate_item_equal -> Item_field::find_item_equal -> Item_equal::contains
---disable_parsing # not yet fixed
+set @save_optimizer_switch=@@optimizer_switch;
+SET @@optimizer_switch = 'semijoin=off';
CREATE TABLE t1 ( f3 int(11), f10 varchar(1), f11 varchar(1)) ;
INSERT IGNORE INTO t1 VALUES (6,'f','f'),(2,'d','d');
CREATE TABLE t2 ( f12 int(11), f13 int(11)) ;
-
-set @save_optimizer_switch=@@optimizer_switch;
-set @@optimizer_switch='materialization=off,in_to_exists=on,semijoin=off';
+insert into t2 values (1,2), (3,4);
EXPLAIN
SELECT * FROM t2
-WHERE (f12) IN (
- SELECT alias2.f3
- FROM t1 AS alias1, t1 AS alias2
- WHERE (alias2.f10 = alias1.f11) AND
- (alias1.f11 OR alias1.f3 = 50 AND alias1.f10));
-
+WHERE ( f12 ) IN (
+ SELECT alias2.f3
+ FROM t1 AS alias1 JOIN t1 AS alias2 ON alias2.f10 = alias1.f11
+ WHERE alias1.f11 OR alias1.f3 = 50 AND alias1.f10
+);
SELECT * FROM t2
-WHERE (f12) IN (
- SELECT alias2.f3
- FROM t1 AS alias1, t1 AS alias2
- WHERE (alias2.f10 = alias1.f11) AND
- (alias1.f11 OR alias1.f3 = 50 AND alias1.f10));
-
-insert into t2 values (1,2), (3,4);
+WHERE ( f12 ) IN (
+ SELECT alias2.f3
+ FROM t1 AS alias1 JOIN t1 AS alias2 ON alias2.f10 = alias1.f11
+ WHERE alias1.f11 OR alias1.f3 = 50 AND alias1.f10
+);
EXPLAIN
SELECT * FROM t2
-WHERE (f12) IN (
- SELECT alias2.f3
- FROM t1 AS alias1, t1 AS alias2
- WHERE (alias2.f10 = alias1.f11) AND
- (alias1.f11 OR alias1.f3 = 50 AND alias1.f10));
-
+WHERE ( f12 ) IN (
+ SELECT alias2.f3
+ FROM t1 AS alias1, t1 AS alias2
+ WHERE (alias2.f10 = alias1.f11) AND (alias1.f11 OR alias1.f3 = 50 AND alias1.f10));
SELECT * FROM t2
-WHERE (f12) IN (
- SELECT alias2.f3
- FROM t1 AS alias1, t1 AS alias2
- WHERE (alias2.f10 = alias1.f11) AND
- (alias1.f11 OR alias1.f3 = 50 AND alias1.f10));
-
-set session optimizer_switch=@save_optimizer_switch;
+WHERE ( f12 ) IN (
+ SELECT alias2.f3
+ FROM t1 AS alias1, t1 AS alias2
+ WHERE (alias2.f10 = alias1.f11) AND (alias1.f11 OR alias1.f3 = 50 AND alias1.f10));
+set @@optimizer_switch=@save_optimizer_switch;
drop table t1, t2;
---enable_parsing
+
+--echo #
+--echo # MWL#89: test introduced after Sergey Petrunia's review - test that
+--echo # keyparts wihtout index prefix are used with the IN-EXISTS strategy.
+--echo #
+
+create table t1 (c1 int);
+insert into t1 values (1), (2), (3);
+
+create table t2 (kp1 int, kp2 int, c2 int, filler char(100));
+insert into t2 values (0,0,0,'filler'),(0,1,1,'filler'),(0,2,2,'filler'),(0,3,3,'filler');
+
+create index key1 on t2 (kp1, kp2);
+create index key2 on t2 (kp1);
+create index key3 on t2 (kp2);
+
+set session optimizer_switch='default';
+
+analyze table t2;
+
+explain
+select c1 from t1 where c1 in (select kp1 from t2 where kp2 = 10 and c2 = 4) or c1 > 7;
+select c1 from t1 where c1 in (select kp1 from t2 where kp2 = 10 and c2 = 4) or c1 > 7;
+
+drop table t1, t2;
diff --git a/sql/item_cmpfunc.cc b/sql/item_cmpfunc.cc
index c2c592e2b88..ab3c2422f30 100644
--- a/sql/item_cmpfunc.cc
+++ b/sql/item_cmpfunc.cc
@@ -2096,13 +2096,14 @@ Item *Item_in_optimizer::transform(Item_transformer transformer, uchar *argument
bool Item_in_optimizer::is_expensive_processor(uchar *arg)
{
- return args[1]->is_expensive_processor(arg);
+ return args[0]->is_expensive_processor(arg) ||
+ args[1]->is_expensive_processor(arg);
}
bool Item_in_optimizer::is_expensive()
{
- return args[1]->is_expensive();
+ return args[0]->is_expensive() || args[1]->is_expensive();
}
diff --git a/sql/item_subselect.h b/sql/item_subselect.h
index 8d2580cc604..1b1be973cf9 100644
--- a/sql/item_subselect.h
+++ b/sql/item_subselect.h
@@ -464,7 +464,7 @@ public:
Item_in_subselect()
:Item_exists_subselect(), left_expr_cache(0), first_execution(TRUE),
optimizer(0), abort_on_null(0),
- pushed_cond_guards(NULL), func(NULL), in_strategy(0),
+ pushed_cond_guards(NULL), func(NULL), in_strategy(SUBS_NOT_TRANSFORMED),
upper_item(0)
{}
void cleanup();
diff --git a/sql/opt_subselect.cc b/sql/opt_subselect.cc
index a9aa4d0b11d..fb573e3b31c 100644
--- a/sql/opt_subselect.cc
+++ b/sql/opt_subselect.cc
@@ -205,18 +205,19 @@ int check_and_do_in_subquery_rewrites(JOIN *join)
!optimizer_flag(thd, OPTIMIZER_SWITCH_MATERIALIZATION))
my_error(ER_ILLEGAL_SUBQUERY_OPTIMIZER_SWITCHES, MYF(0));
+ /*
+ If the subquery predicate is IN/=ANY, analyse and set all possible
+ subquery execution strategies based on optimizer switches and syntactic
+ properties.
+ */
if (in_subs)
{
- /* Subquery predicate is an IN/=ANY predicate. */
- if (optimizer_flag(thd, OPTIMIZER_SWITCH_IN_TO_EXISTS))
- in_subs->in_strategy|= SUBS_IN_TO_EXISTS;
- if (optimizer_flag(thd, OPTIMIZER_SWITCH_MATERIALIZATION))
- in_subs->in_strategy|= SUBS_MATERIALIZATION;
-
/*
Check if the subquery predicate can be executed via materialization.
The required conditions are:
- 1. Subquery is a single SELECT (not a UNION)
+ 0. The materialization optimizer switch was set.
+ 1. Subquery is a single SELECT (not a UNION).
+ TODO: this is a limitation that can be fixed
2. Subquery is not a table-less query. In this case there is no
point in materializing.
2A The upper query is not a table-less SELECT ... FROM DUAL. We
@@ -230,7 +231,7 @@ int check_and_do_in_subquery_rewrites(JOIN *join)
non-top-level queries because it cannot handle NULLs correctly.
4. Subquery is non-correlated
TODO:
- This is an overly restrictive condition. It can be extended to:
+ This condition is too restrictive (limitation). It can be extended to:
(Subquery is non-correlated ||
Subquery is correlated to any query outer to IN predicate ||
(Subquery is correlated to the immediate outer query &&
@@ -240,30 +241,30 @@ int check_and_do_in_subquery_rewrites(JOIN *join)
(*) The subquery must be part of a SELECT statement. The current
condition also excludes multi-table update statements.
*/
- if (!(in_subs->in_strategy & SUBS_MATERIALIZATION &&
- !select_lex->is_part_of_union() && // 1
- parent_unit->first_select()->leaf_tables && // 2
- thd->lex->sql_command == SQLCOM_SELECT && // *
- select_lex->outer_select()->leaf_tables && // 2A
- subquery_types_allow_materialization(in_subs) &&
- // psergey-todo: duplicated_subselect_card_check: where it's done?
- (in_subs->is_top_level_item() || //3
- optimizer_flag(thd,
- OPTIMIZER_SWITCH_PARTIAL_MATCH_ROWID_MERGE) || //3
- optimizer_flag(thd,
- OPTIMIZER_SWITCH_PARTIAL_MATCH_TABLE_SCAN)) && //3
- !in_subs->is_correlated)) //4
+ if (optimizer_flag(thd, OPTIMIZER_SWITCH_MATERIALIZATION) && // 0
+ !select_lex->is_part_of_union() && // 1
+ parent_unit->first_select()->leaf_tables && // 2
+ thd->lex->sql_command == SQLCOM_SELECT && // *
+ select_lex->outer_select()->leaf_tables && // 2A
+ subquery_types_allow_materialization(in_subs) &&
+ (in_subs->is_top_level_item() || //3
+ optimizer_flag(thd,
+ OPTIMIZER_SWITCH_PARTIAL_MATCH_ROWID_MERGE) || //3
+ optimizer_flag(thd,
+ OPTIMIZER_SWITCH_PARTIAL_MATCH_TABLE_SCAN)) && //3
+ !in_subs->is_correlated) //4
{
- /* Materialization is not possible based on syntactic properties. */
- in_subs->in_strategy&= ~SUBS_MATERIALIZATION;
+ in_subs->in_strategy|= SUBS_MATERIALIZATION;
}
- if (!in_subs->in_strategy)
+ /*
+ IN-TO-EXISTS is the only universal strategy. Choose it if the user
+ allowed it via an optimizer switch, or if materialization is not
+ possible.
+ */
+ if (optimizer_flag(thd, OPTIMIZER_SWITCH_IN_TO_EXISTS) ||
+ !in_subs->in_strategy)
{
- /*
- If neither materialization is possible, nor the user chose
- IN-TO-EXISTS, choose IN-TO-EXISTS as the only universal strategy.
- */
in_subs->in_strategy|= SUBS_IN_TO_EXISTS;
}
}
@@ -3703,10 +3704,9 @@ bool JOIN::choose_subquery_plan(table_map join_tables)
enum_reopt_result reopt_result= REOPT_NONE;
Item_in_subselect *in_subs;
- if (select_lex->master_unit()->item &&
- select_lex->master_unit()->item->is_in_predicate())
+ if (is_in_subquery())
{
- in_subs= (Item_in_subselect*) select_lex->master_unit()->item;
+ in_subs= (Item_in_subselect*) unit->item;
if (in_subs->create_in_to_exists_cond(this))
return true;
}
@@ -3943,11 +3943,10 @@ bool JOIN::choose_subquery_plan(table_map join_tables)
bool JOIN::choose_tableless_subquery_plan()
{
DBUG_ASSERT(!tables_list || !tables);
- if (select_lex->master_unit()->item)
+ if (unit->item)
{
- DBUG_ASSERT(select_lex->master_unit()->item->type() ==
- Item::SUBSELECT_ITEM);
- Item_subselect *subs_predicate= select_lex->master_unit()->item;
+ DBUG_ASSERT(unit->item->type() == Item::SUBSELECT_ITEM);
+ Item_subselect *subs_predicate= unit->item;
/*
If the optimizer determined that his query has an empty result,
@@ -3990,4 +3989,3 @@ bool JOIN::choose_tableless_subquery_plan()
}
return FALSE;
}
-
diff --git a/sql/sql_lex.cc b/sql/sql_lex.cc
index f1640bf71ed..48f0b3bdbd5 100644
--- a/sql/sql_lex.cc
+++ b/sql/sql_lex.cc
@@ -3123,7 +3123,7 @@ bool st_select_lex::optimize_unflattened_subqueries()
un->set_limit(un->global_parameters);
un->thd->lex->current_select= sl;
save_options= inner_join->select_options;
- if (un->outer_select()->options & SELECT_DESCRIBE)
+ if (options & SELECT_DESCRIBE)
{
/* Optimize the subquery in the context of EXPLAIN. */
sl->set_explain_type();
diff --git a/sql/sql_list.h b/sql/sql_list.h
index e90f16aeb99..7d9f3d26ec8 100644
--- a/sql/sql_list.h
+++ b/sql/sql_list.h
@@ -260,7 +260,7 @@ public:
list_node *node= first;
list_node *list_first= list->first;
elements=0;
- while (node->info && node != list_first)
+ while (node != &end_of_list && node != list_first)
{
prev= &node->next;
node= node->next;
diff --git a/sql/sql_select.cc b/sql/sql_select.cc
index 151c22dc52c..76b1e182eb0 100644
--- a/sql/sql_select.cc
+++ b/sql/sql_select.cc
@@ -57,7 +57,8 @@ static bool update_ref_and_keys(THD *thd, DYNAMIC_ARRAY *keyuse,
uint tables, COND *conds,
table_map table_map, SELECT_LEX *select_lex,
st_sargable_param **sargables);
-static bool sort_and_filter_keyuse(DYNAMIC_ARRAY *keyuse);
+static bool sort_and_filter_keyuse(DYNAMIC_ARRAY *keyuse,
+ bool skip_unprefixed_keyparts);
static int sort_keyuse(KEYUSE *a,KEYUSE *b);
static bool create_ref_for_key(JOIN *join, JOIN_TAB *j, KEYUSE *org_keyuse,
table_map used_tables);
@@ -914,7 +915,6 @@ JOIN::optimize()
"Impossible HAVING" : "Impossible WHERE";
tables= 0;
error= 0;
- choose_tableless_subquery_plan();
goto setup_subq_exit;
}
}
@@ -966,7 +966,6 @@ JOIN::optimize()
zero_result_cause= "No matching min/max row";
tables= 0;
error=0;
- choose_tableless_subquery_plan();
goto setup_subq_exit;
}
if (res > 1)
@@ -1007,7 +1006,6 @@ JOIN::optimize()
{
DBUG_PRINT("info",("No tables"));
error= 0;
- choose_tableless_subquery_plan();
goto setup_subq_exit;
}
error= -1; // Error is sent to client
@@ -1508,6 +1506,9 @@ JOIN::optimize()
DBUG_RETURN(0);
setup_subq_exit:
+ /* Choose an execution strategy for this JOIN. */
+ if (!tables_list || !tables)
+ choose_tableless_subquery_plan();
/*
Even with zero matching rows, subqueries in the HAVING clause may
need to be evaluated if there are aggregate functions in the query.
@@ -3036,7 +3037,16 @@ make_join_statistics(JOIN *join, TABLE_LIST *tables_arg, COND *conds,
if (update_ref_and_keys(join->thd, keyuse_array, stat, join->tables,
conds, ~outer_join, join->select_lex, &sargables))
goto error;
- if (keyuse_array->elements && sort_and_filter_keyuse(keyuse_array))
+ /*
+ Keyparts without prefixes may be useful if this JOIN is a subquery, and
+ if the subquery may be executed via the IN-EXISTS strategy.
+ */
+ bool skip_unprefixed_keyparts=
+ !(join->is_in_subquery() &&
+ ((Item_in_subselect*)join->unit->item)->in_strategy & SUBS_IN_TO_EXISTS);
+
+ if (keyuse_array->elements &&
+ sort_and_filter_keyuse(keyuse_array, skip_unprefixed_keyparts))
goto error;
DBUG_EXECUTE("opt", print_keyuse_array(keyuse_array););
}
@@ -4505,7 +4515,8 @@ update_ref_and_keys(THD *thd, DYNAMIC_ARRAY *keyuse,JOIN_TAB *join_tab,
Special treatment for ft-keys.
*/
-static bool sort_and_filter_keyuse(DYNAMIC_ARRAY *keyuse)
+static bool sort_and_filter_keyuse(DYNAMIC_ARRAY *keyuse,
+ bool skip_unprefixed_keyparts)
{
KEYUSE key_end, *prev, *save_pos, *use;
uint found_eq_constant, i;
@@ -4532,12 +4543,12 @@ static bool sort_and_filter_keyuse(DYNAMIC_ARRAY *keyuse)
{
if (use->key == prev->key && use->table == prev->table)
{
- if (prev->keypart+1 < use->keypart ||
+ if ((prev->keypart+1 < use->keypart && skip_unprefixed_keyparts) ||
(prev->keypart == use->keypart && found_eq_constant))
continue; /* remove */
}
- else if (use->keypart != 0) // First found must be 0
- continue;
+ else if (use->keypart != 0 && skip_unprefixed_keyparts)
+ continue; /* remove - first found must be 0 */
}
prev= use;
@@ -16938,8 +16949,7 @@ create_sort_index(THD *thd, JOIN *join, ORDER *order,
select= tab->select;
/* Currently ORDER BY ... LIMIT is not supported in subqueries. */
- DBUG_ASSERT(join->group_list ||
- !(join->unit->item && join->unit->item->is_in_predicate()));
+ DBUG_ASSERT(join->group_list || !join->is_in_subquery());
/*
When there is SQL_BIG_RESULT do not sort using index for GROUP BY,
@@ -20659,7 +20669,7 @@ JOIN::reoptimize(Item *added_where, table_map join_tables,
/* added_keyuse contents is copied, and it is no longer needed. */
delete_dynamic(&added_keyuse);
- if (sort_and_filter_keyuse(&keyuse))
+ if (sort_and_filter_keyuse(&keyuse, true))
return REOPT_ERROR;
optimize_keyuse(this, &keyuse);
diff --git a/sql/sql_select.h b/sql/sql_select.h
index f6862c46554..f67b79fff47 100644
--- a/sql/sql_select.h
+++ b/sql/sql_select.h
@@ -1083,6 +1083,11 @@ public:
double *read_time_arg, double *record_count_arg);
/* defined in opt_subselect.cc */
bool transform_max_min_subquery();
+ /* True if this JOIN is a subquery under an IN predicate. */
+ bool is_in_subquery()
+ {
+ return (unit->item && unit->item->is_in_predicate());
+ }
private:
/**
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