From 592b7fbac9cfdd47a1f360e55465b250f2432254 Mon Sep 17 00:00:00 2001
From: Igor Babaev <igor@askmonty.org>
Date: Tue, 28 Oct 2014 14:33:31 -0700
Subject: [PATCH] Fixed bug mdev-6325.
Field::selectivity should be set for all fields used in range conditions.
---
mysql-test/r/selectivity.result | 35 ++++++++++++++++++++++++
mysql-test/r/selectivity_innodb.result | 35 ++++++++++++++++++++++++
mysql-test/t/selectivity.test | 25 +++++++++++++++++
sql/opt_range.cc | 38 ++++++++++++++++++--------
sql/sql_select.cc | 3 +-
5 files changed, 123 insertions(+), 13 deletions(-)
diff --git a/mysql-test/r/selectivity.result b/mysql-test/r/selectivity.result
index 9899b894ff6..088e169ed0c 100644
--- a/mysql-test/r/selectivity.result
+++ b/mysql-test/r/selectivity.result
@@ -1346,4 +1346,39 @@ foo foo 1
foo foo 2
set optimizer_use_condition_selectivity=@save_optimizer_use_condition_selectivity;
DROP TABLE t1,t2;
+#
+# Bug mdev-6325: wrong selectivity of a column with ref access
+#
+create table t0(a int);
+insert into t0 values (0),(1),(2),(3),(4),(5),(6),(7),(8),(9);
+create table t1(a int);
+insert into t1 select A.a + B.a* 10 + C.a * 100 from t0 A, t0 B, t0 C;
+create table t2 (a int, b int, key(a));
+insert into t2 select A.a + 10*B.a, 12345 from t0 A, t0 B, t0 C;
+set use_stat_tables='preferably';
+set histogram_size=100;
+set optimizer_use_condition_selectivity=4;
+analyze table t1 persistent for all;
+Table Op Msg_type Msg_text
+test.t1 analyze status Engine-independent statistics collected
+test.t1 analyze status OK
+analyze table t2 persistent for all;
+Table Op Msg_type Msg_text
+test.t2 analyze status Engine-independent statistics collected
+test.t2 analyze status Table is already up to date
+explain extended
+select * from t1 straight_join t2 where t1.a=t2.a and t1.a<10;
+id select_type table type possible_keys key key_len ref rows filtered Extra
+1 SIMPLE t1 ALL NULL NULL NULL NULL 1000 0.99 Using where
+1 SIMPLE t2 ref a a 5 test.t1.a 10 100.00
+Warnings:
+Note 1003 select `test`.`t1`.`a` AS `a`,`test`.`t2`.`a` AS `a`,`test`.`t2`.`b` AS `b` from `test`.`t1` straight_join `test`.`t2` where ((`test`.`t2`.`a` = `test`.`t1`.`a`) and (`test`.`t1`.`a` < 10))
+explain extended
+select * from t1 straight_join t2 where t1.a=t2.a and t2.a<10;
+id select_type table type possible_keys key key_len ref rows filtered Extra
+1 SIMPLE t1 ALL NULL NULL NULL NULL 1000 0.99 Using where
+1 SIMPLE t2 ref a a 5 test.t1.a 10 100.00
+Warnings:
+Note 1003 select `test`.`t1`.`a` AS `a`,`test`.`t2`.`a` AS `a`,`test`.`t2`.`b` AS `b` from `test`.`t1` straight_join `test`.`t2` where ((`test`.`t2`.`a` = `test`.`t1`.`a`) and (`test`.`t1`.`a` < 10))
+drop table t0,t1,t2;
set use_stat_tables=@save_use_stat_tables;
diff --git a/mysql-test/r/selectivity_innodb.result b/mysql-test/r/selectivity_innodb.result
index 013fb1d876c..af9c31afae1 100644
--- a/mysql-test/r/selectivity_innodb.result
+++ b/mysql-test/r/selectivity_innodb.result
@@ -1356,6 +1356,41 @@ foo foo 1
foo foo 2
set optimizer_use_condition_selectivity=@save_optimizer_use_condition_selectivity;
DROP TABLE t1,t2;
+#
+# Bug mdev-6325: wrong selectivity of a column with ref access
+#
+create table t0(a int);
+insert into t0 values (0),(1),(2),(3),(4),(5),(6),(7),(8),(9);
+create table t1(a int);
+insert into t1 select A.a + B.a* 10 + C.a * 100 from t0 A, t0 B, t0 C;
+create table t2 (a int, b int, key(a));
+insert into t2 select A.a + 10*B.a, 12345 from t0 A, t0 B, t0 C;
+set use_stat_tables='preferably';
+set histogram_size=100;
+set optimizer_use_condition_selectivity=4;
+analyze table t1 persistent for all;
+Table Op Msg_type Msg_text
+test.t1 analyze status Engine-independent statistics collected
+test.t1 analyze status OK
+analyze table t2 persistent for all;
+Table Op Msg_type Msg_text
+test.t2 analyze status Engine-independent statistics collected
+test.t2 analyze status OK
+explain extended
+select * from t1 straight_join t2 where t1.a=t2.a and t1.a<10;
+id select_type table type possible_keys key key_len ref rows filtered Extra
+1 SIMPLE t1 ALL NULL NULL NULL NULL 1000 0.99 Using where
+1 SIMPLE t2 ref a a 5 test.t1.a 10 100.00
+Warnings:
+Note 1003 select `test`.`t1`.`a` AS `a`,`test`.`t2`.`a` AS `a`,`test`.`t2`.`b` AS `b` from `test`.`t1` straight_join `test`.`t2` where ((`test`.`t2`.`a` = `test`.`t1`.`a`) and (`test`.`t1`.`a` < 10))
+explain extended
+select * from t1 straight_join t2 where t1.a=t2.a and t2.a<10;
+id select_type table type possible_keys key key_len ref rows filtered Extra
+1 SIMPLE t1 ALL NULL NULL NULL NULL 1000 0.99 Using where
+1 SIMPLE t2 ref a a 5 test.t1.a 10 100.00
+Warnings:
+Note 1003 select `test`.`t1`.`a` AS `a`,`test`.`t2`.`a` AS `a`,`test`.`t2`.`b` AS `b` from `test`.`t1` straight_join `test`.`t2` where ((`test`.`t2`.`a` = `test`.`t1`.`a`) and (`test`.`t1`.`a` < 10))
+drop table t0,t1,t2;
set use_stat_tables=@save_use_stat_tables;
set optimizer_switch=@save_optimizer_switch_for_selectivity_test;
set @tmp_ust= @@use_stat_tables;
diff --git a/mysql-test/t/selectivity.test b/mysql-test/t/selectivity.test
index 8cb2620550e..16226b07751 100644
--- a/mysql-test/t/selectivity.test
+++ b/mysql-test/t/selectivity.test
@@ -889,4 +889,29 @@ set optimizer_use_condition_selectivity=@save_optimizer_use_condition_selectivit
DROP TABLE t1,t2;
+--echo #
+--echo # Bug mdev-6325: wrong selectivity of a column with ref access
+--echo #
+
+create table t0(a int);
+insert into t0 values (0),(1),(2),(3),(4),(5),(6),(7),(8),(9);
+create table t1(a int);
+insert into t1 select A.a + B.a* 10 + C.a * 100 from t0 A, t0 B, t0 C;
+create table t2 (a int, b int, key(a));
+insert into t2 select A.a + 10*B.a, 12345 from t0 A, t0 B, t0 C;
+
+set use_stat_tables='preferably';
+set histogram_size=100;
+
+set optimizer_use_condition_selectivity=4;
+analyze table t1 persistent for all;
+analyze table t2 persistent for all;
+
+explain extended
+select * from t1 straight_join t2 where t1.a=t2.a and t1.a<10;
+explain extended
+select * from t1 straight_join t2 where t1.a=t2.a and t2.a<10;
+
+drop table t0,t1,t2;
+
set use_stat_tables=@save_use_stat_tables;
diff --git a/sql/opt_range.cc b/sql/opt_range.cc
index 00e81767203..6871a6bd0af 100644
--- a/sql/opt_range.cc
+++ b/sql/opt_range.cc
@@ -3487,6 +3487,8 @@ bool calculate_cond_selectivity_for_table(THD *thd, TABLE *table, Item *cond)
my_bitmap_init(&handled_columns, buf, table->s->fields, FALSE);
/*
+ Calculate the selectivity of the range conditions supported by indexes.
+
First, take into account possible range accesses.
range access estimates are the most precise, we prefer them to any other
estimate sources.
@@ -3532,6 +3534,7 @@ bool calculate_cond_selectivity_for_table(THD *thd, TABLE *table, Item *cond)
break;
bitmap_set_bit(&handled_columns, key_part->fieldnr-1);
}
+ double selectivity_mult;
if (i)
{
/*
@@ -3547,7 +3550,6 @@ bool calculate_cond_selectivity_for_table(THD *thd, TABLE *table, Item *cond)
*/
double f1= key_info->actual_rec_per_key(i-1);
double f2= key_info->actual_rec_per_key(i);
- double selectivity_mult;
if (f1 > 0 && f2 > 0)
selectivity_mult= f1 / f2;
else
@@ -3559,8 +3561,23 @@ bool calculate_cond_selectivity_for_table(THD *thd, TABLE *table, Item *cond)
*/
selectivity_mult= ((double)(i+1)) / i;
}
- table->cond_selectivity*= selectivity_mult;
+ table->cond_selectivity*= selectivity_mult;
}
+ /*
+ We need to set selectivity for fields supported by indexes.
+ For single-component indexes and for some first components
+ of other indexes we do it here. For the remaining fields
+ we do it later in this function, in the same way as for the
+ fields not used in any indexes.
+ */
+ if (i == 1)
+ {
+ uint fieldnr= key_info->key_part[0].fieldnr;
+ table->field[fieldnr-1]->cond_selectivity= quick_cond_selectivity;
+ if (i != used_key_parts)
+ table->field[fieldnr-1]->cond_selectivity*= selectivity_mult;
+ bitmap_clear_bit(used_fields, fieldnr-1);
+ }
}
}
}
@@ -3568,10 +3585,9 @@ bool calculate_cond_selectivity_for_table(THD *thd, TABLE *table, Item *cond)
/*
Second step: calculate the selectivity of the range conditions not
- supported by any index
+ supported by any index and selectivity of the range condition
+ over the fields whose selectivity has not been set yet.
*/
- bitmap_subtract(used_fields, &handled_columns);
- /* no need to do: my_bitmap_free(&handled_columns); */
if (thd->variables.optimizer_use_condition_selectivity > 2 &&
!bitmap_is_clear_all(used_fields))
@@ -3647,9 +3663,12 @@ bool calculate_cond_selectivity_for_table(THD *thd, TABLE *table, Item *cond)
for (Field **field_ptr= table->field; *field_ptr; field_ptr++)
{
Field *table_field= *field_ptr;
- if (bitmap_is_set(table->read_set, table_field->field_index) &&
+ if (bitmap_is_set(used_fields, table_field->field_index) &&
table_field->cond_selectivity < 1.0)
- table->cond_selectivity*= table_field->cond_selectivity;
+ {
+ if (!bitmap_is_set(&handled_columns, table_field->field_index))
+ table->cond_selectivity*= table_field->cond_selectivity;
+ }
}
free_alloc:
@@ -3658,10 +3677,7 @@ bool calculate_cond_selectivity_for_table(THD *thd, TABLE *table, Item *cond)
}
- /* Calculate the selectivity of the range conditions supported by indexes */
-
- bitmap_clear_all(used_fields);
-
+ bitmap_union(used_fields, &handled_columns);
/* Check if we can improve selectivity estimates by using sampling */
ulong check_rows=
diff --git a/sql/sql_select.cc b/sql/sql_select.cc
index 127c73ca873..636b5702a93 100644
--- a/sql/sql_select.cc
+++ b/sql/sql_select.cc
@@ -4407,8 +4407,7 @@ add_key_field(JOIN *join,
if (is_const)
{
stat[0].const_keys.merge(possible_keys);
- if (possible_keys.is_clear_all())
- bitmap_set_bit(&field->table->cond_set, field->field_index);
+ bitmap_set_bit(&field->table->cond_set, field->field_index);
}
else if (!eq_func)
{
--
2.30.9