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#
# Engine-agnostic tests for statistics-based selectivity calculations.
# - selectivity tests that depend on the engine should go into
# t/selectivity.test. That test is run with myisam/innodb/xtradb.
# - this file is for tests that don't depend on the engine.
#
drop table if exists t0,t1,t2,t3;
select @@global.use_stat_tables;
@@global.use_stat_tables
COMPLEMENTARY
select @@session.use_stat_tables;
@@session.use_stat_tables
COMPLEMENTARY
set @save_use_stat_tables=@@use_stat_tables;
set use_stat_tables='preferably';
set @save_optimizer_use_condition_selectivity=@@optimizer_use_condition_selectivity;
set @save_histogram_size=@@histogram_size;
set @save_histogram_type=@@histogram_type;
#
# MDEV-5917: EITS: different order of predicates in IN (...) causes different estimates
#
create table t1(a int);
insert into t1 values (0),(1),(2),(3),(4),(5),(6),(7),(8),(9);
create table t2 (col1 int);
# one value in 1..100 range
insert into t2 select A.a + B.a*10 from t1 A, t1 B;
# ten values in 100...200 range
insert into t2 select 100 + A.a + B.a*10 from t1 A, t1 B, t1 C;
set histogram_type='SINGLE_PREC_HB';
set histogram_size=100;
set optimizer_use_condition_selectivity=4;
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
# The following two must have the same in 'Extra' column:
explain extended select * from t2 where col1 IN (20, 180);
id select_type table type possible_keys key key_len ref rows filtered Extra
1 SIMPLE t2 ALL NULL NULL NULL NULL 1100 1.35 Using where
Warnings:
Note 1003 select `test`.`t2`.`col1` AS `col1` from `test`.`t2` where (`test`.`t2`.`col1` in (20,180))
explain extended select * from t2 where col1 IN (180, 20);
id select_type table type possible_keys key key_len ref rows filtered Extra
1 SIMPLE t2 ALL NULL NULL NULL NULL 1100 1.35 Using where
Warnings:
Note 1003 select `test`.`t2`.`col1` AS `col1` from `test`.`t2` where (`test`.`t2`.`col1` in (180,20))
drop table t1, t2;
#
# MDEV-5926: EITS: Histogram estimates for column=least_possible_value are wrong
#
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 from t0 A, t0 B, t0 C;
set histogram_size=20;
set histogram_type='single_prec_hb';
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
set use_stat_tables='preferably';
set optimizer_use_condition_selectivity=4;
# Should select about 10%:
explain extended select * from t1 where a=2;
id select_type table type possible_keys key key_len ref rows filtered Extra
1 SIMPLE t1 ALL NULL NULL NULL NULL 1000 9.52 Using where
Warnings:
Note 1003 select `test`.`t1`.`a` AS `a` from `test`.`t1` where (`test`.`t1`.`a` = 2)
# Should select about 10%:
explain extended select * from t1 where a=1;
id select_type table type possible_keys key key_len ref rows filtered Extra
1 SIMPLE t1 ALL NULL NULL NULL NULL 1000 9.52 Using where
Warnings:
Note 1003 select `test`.`t1`.`a` AS `a` from `test`.`t1` where (`test`.`t1`.`a` = 1)
# Must not have filtered=100%:
explain extended select * from t1 where a=0;
id select_type table type possible_keys key key_len ref rows filtered Extra
1 SIMPLE t1 ALL NULL NULL NULL NULL 1000 9.52 Using where
Warnings:
Note 1003 select `test`.`t1`.`a` AS `a` from `test`.`t1` where (`test`.`t1`.`a` = 0)
# Again, must not have filtered=100%:
explain extended select * from t1 where a=-1;
id select_type table type possible_keys key key_len ref rows filtered Extra
1 SIMPLE t1 ALL NULL NULL NULL NULL 1000 9.52 Using where
Warnings:
Note 1003 select `test`.`t1`.`a` AS `a` from `test`.`t1` where (`test`.`t1`.`a` = <cache>(-(1)))
drop table t0, t1;
#
# MDEV-4362: Selectivity estimates for IN (...) do not depend on whether the values are in range
#
create table t1 (col1 int);
set @a=-1;
create table t2 (a int) select (@a:=@a+1) as a from information_schema.session_variables A limit 100;
insert into t1 select A.a from t2 A, t2 B where A.a < 100 and B.a < 100;
select min(col1), max(col1), count(*) from t1;
min(col1) max(col1) count(*)
0 99 10000
set histogram_size=100;
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
explain extended select * from t1 where col1 in (1,2,3);
id select_type table type possible_keys key key_len ref rows filtered Extra
1 SIMPLE t1 ALL NULL NULL NULL NULL 10000 3.37 Using where
Warnings:
Note 1003 select `test`.`t1`.`col1` AS `col1` from `test`.`t1` where (`test`.`t1`.`col1` in (1,2,3))
# Must not cause fp division by zero, or produce nonsense numbers:
explain extended select * from t1 where col1 in (-1,-2,-3);
id select_type table type possible_keys key key_len ref rows filtered Extra
1 SIMPLE t1 ALL NULL NULL NULL NULL 10000 5.94 Using where
Warnings:
Note 1003 select `test`.`t1`.`col1` AS `col1` from `test`.`t1` where (`test`.`t1`.`col1` in (<cache>(-(1)),<cache>(-(2)),<cache>(-(3))))
explain extended select * from t1 where col1<=-1;
id select_type table type possible_keys key key_len ref rows filtered Extra
1 SIMPLE t1 ALL NULL NULL NULL NULL 10000 1.00 Using where
Warnings:
Note 1003 select `test`.`t1`.`col1` AS `col1` from `test`.`t1` where (`test`.`t1`.`col1` <= <cache>(-(1)))
drop table t1, t2;
#
# End of the test file
#
set use_stat_tables= @save_use_stat_tables;
set histogram_type=@save_histogram_type;
set histogram_size=@save_histogram_size;
set optimizer_use_condition_selectivity=@save_optimizer_use_condition_selectivity;
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