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Igor Babaev 2014-10-28 16:31:26 -07:00
commit 2d088e265c
5 changed files with 123 additions and 13 deletions
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35
mysql-test/r/selectivity.result
View File

@ -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;

35
mysql-test/r/selectivity_innodb.result
View File

@ -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;

25
mysql-test/t/selectivity.test
View File

@ -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;

38
sql/opt_range.cc
View File

@ -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=

3
sql/sql_select.cc
View File

@ -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)
{