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MDEV-16374: Filtered shows 0 for materilization scan for a semi join, which makes optimizer always picks

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materialization scan over materialization lookup

For non-mergeable semi-joins we don't store the estimates of the IN subquery in table->file->stats.records.
In the function TABLE_LIST::fetch_number_of_rows, we store the number of rows in the tables
(estimates in case of derived table/views).
Currently we don't store the estimates for non-mergeable semi-joins, which leads to a problem of selecting
materialization scan over materialization lookup.
Fixed this by storing these estimated appropriately
This commit is contained in:
Varun Gupta 2018-06-09 11:26:52 +05:30
parent 15155ecd34
commit cd33280b68
5 changed files with 161 additions and 11 deletions
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70
mysql-test/r/selectivity.result
View File

@ -356,13 +356,13 @@ and o_orderkey = l_orderkey
group by c_name, c_custkey, o_orderkey, o_orderdate, o_totalprice group by c_name, c_custkey, o_orderkey, o_orderdate, o_totalprice
order by o_totalprice desc, o_orderdate; order by o_totalprice desc, o_orderdate;
id select_type table type possible_keys key key_len ref rows filtered Extra id select_type table type possible_keys key key_len ref rows filtered Extra
1 PRIMARY <subquery2> ALL distinct_key NULL NULL NULL 6005 0.00 Using temporary; Using filesort 1 PRIMARY orders ALL PRIMARY,i_o_custkey NULL NULL NULL 1500 100.00 Using where; Using temporary; Using filesort
1 PRIMARY orders eq_ref PRIMARY,i_o_custkey PRIMARY 4 <subquery2>.l_orderkey 1 100.00 Using where 1 PRIMARY <subquery2> eq_ref distinct_key distinct_key 4 dbt3_s001.orders.o_orderkey 1 100.00
1 PRIMARY customer eq_ref PRIMARY PRIMARY 4 dbt3_s001.orders.o_custkey 1 100.00 1 PRIMARY customer eq_ref PRIMARY PRIMARY 4 dbt3_s001.orders.o_custkey 1 100.00
1 PRIMARY lineitem ref PRIMARY,i_l_orderkey,i_l_orderkey_quantity PRIMARY 4 <subquery2>.l_orderkey 4 100.00 1 PRIMARY lineitem ref PRIMARY,i_l_orderkey,i_l_orderkey_quantity i_l_orderkey_quantity 4 dbt3_s001.orders.o_orderkey 4 100.00 Using index
2 MATERIALIZED lineitem index NULL i_l_orderkey_quantity 13 NULL 6005 100.00 Using index 2 MATERIALIZED lineitem index NULL i_l_orderkey_quantity 13 NULL 6005 100.00 Using index
Warnings: Warnings:
Note 1003 select `dbt3_s001`.`customer`.`c_name` AS `c_name`,`dbt3_s001`.`customer`.`c_custkey` AS `c_custkey`,`dbt3_s001`.`orders`.`o_orderkey` AS `o_orderkey`,`dbt3_s001`.`orders`.`o_orderDATE` AS `o_orderdate`,`dbt3_s001`.`orders`.`o_totalprice` AS `o_totalprice`,sum(`dbt3_s001`.`lineitem`.`l_quantity`) AS `sum(l_quantity)` from <materialize> (select `dbt3_s001`.`lineitem`.`l_orderkey` from `dbt3_s001`.`lineitem` group by `dbt3_s001`.`lineitem`.`l_orderkey` having (sum(`dbt3_s001`.`lineitem`.`l_quantity`) > 250)) join `dbt3_s001`.`customer` join `dbt3_s001`.`orders` join `dbt3_s001`.`lineitem` where ((`dbt3_s001`.`customer`.`c_custkey` = `dbt3_s001`.`orders`.`o_custkey`) and (`dbt3_s001`.`orders`.`o_orderkey` = `<subquery2>`.`l_orderkey`) and (`dbt3_s001`.`lineitem`.`l_orderkey` = `<subquery2>`.`l_orderkey`)) group by `dbt3_s001`.`customer`.`c_name`,`dbt3_s001`.`customer`.`c_custkey`,`dbt3_s001`.`orders`.`o_orderkey`,`dbt3_s001`.`orders`.`o_orderDATE`,`dbt3_s001`.`orders`.`o_totalprice` order by `dbt3_s001`.`orders`.`o_totalprice` desc,`dbt3_s001`.`orders`.`o_orderDATE` Note 1003 select `dbt3_s001`.`customer`.`c_name` AS `c_name`,`dbt3_s001`.`customer`.`c_custkey` AS `c_custkey`,`dbt3_s001`.`orders`.`o_orderkey` AS `o_orderkey`,`dbt3_s001`.`orders`.`o_orderDATE` AS `o_orderdate`,`dbt3_s001`.`orders`.`o_totalprice` AS `o_totalprice`,sum(`dbt3_s001`.`lineitem`.`l_quantity`) AS `sum(l_quantity)` from <materialize> (select `dbt3_s001`.`lineitem`.`l_orderkey` from `dbt3_s001`.`lineitem` group by `dbt3_s001`.`lineitem`.`l_orderkey` having (sum(`dbt3_s001`.`lineitem`.`l_quantity`) > 250)) join `dbt3_s001`.`customer` join `dbt3_s001`.`orders` join `dbt3_s001`.`lineitem` where ((`dbt3_s001`.`customer`.`c_custkey` = `dbt3_s001`.`orders`.`o_custkey`) and (`<subquery2>`.`l_orderkey` = `dbt3_s001`.`orders`.`o_orderkey`) and (`dbt3_s001`.`lineitem`.`l_orderkey` = `dbt3_s001`.`orders`.`o_orderkey`)) group by `dbt3_s001`.`customer`.`c_name`,`dbt3_s001`.`customer`.`c_custkey`,`dbt3_s001`.`orders`.`o_orderkey`,`dbt3_s001`.`orders`.`o_orderDATE`,`dbt3_s001`.`orders`.`o_totalprice` order by `dbt3_s001`.`orders`.`o_totalprice` desc,`dbt3_s001`.`orders`.`o_orderDATE`
select select
c_name, c_custkey, o_orderkey, o_orderdate, o_totalprice, sum(l_quantity) c_name, c_custkey, o_orderkey, o_orderdate, o_totalprice, sum(l_quantity)
from customer, orders, lineitem from customer, orders, lineitem
@ -1535,6 +1535,68 @@ t
10:00:00 10:00:00
11:00:00 11:00:00
DROP TABLE t1; DROP TABLE t1;
#
# MDEV-16374: filtered shows 0 for materilization scan for a semi join, which makes optimizer
# always pick materialization scan over materialization lookup
#
create table t0(a int);
insert into t0 values (0),(1),(2),(3),(4),(5),(6),(7),(8),(9);
create table t1 (a int, b int);
insert into t1 values (0,0),(1,1),(2,2),(3,3),(4,4),(5,5),(6,6),(7,7),(8,8),(9,9),(10,10),
(11,11),(12,12),(13,13),(14,14),(15,15);
set @@optimizer_use_condition_selectivity=2;
explain extended select * from t1 where a in (select max(a) from t1 group by b);
id select_type table type possible_keys key key_len ref rows filtered Extra
1 PRIMARY t1 ALL NULL NULL NULL NULL 16 100.00 Using where
1 PRIMARY <subquery2> eq_ref distinct_key distinct_key 4 test.t1.a 1 100.00
2 MATERIALIZED t1 ALL NULL NULL NULL NULL 16 100.00 Using temporary
Warnings:
Note 1003 select `test`.`t1`.`a` AS `a`,`test`.`t1`.`b` AS `b` from <materialize> (select max(`test`.`t1`.`a`) from `test`.`t1` group by `test`.`t1`.`b`) join `test`.`t1` where (`<subquery2>`.`max(a)` = `test`.`t1`.`a`)
select * from t1 where a in (select max(a) from t1 group by b);
a b
0 0
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set @@optimizer_use_condition_selectivity=1;
explain extended select * from t1 where a in (select max(a) from t1 group by b);
id select_type table type possible_keys key key_len ref rows filtered Extra
1 PRIMARY t1 ALL NULL NULL NULL NULL 16 100.00 Using where
1 PRIMARY <subquery2> eq_ref distinct_key distinct_key 4 test.t1.a 1 100.00
2 MATERIALIZED t1 ALL NULL NULL NULL NULL 16 100.00 Using temporary
Warnings:
Note 1003 select `test`.`t1`.`a` AS `a`,`test`.`t1`.`b` AS `b` from <materialize> (select max(`test`.`t1`.`a`) from `test`.`t1` group by `test`.`t1`.`b`) join `test`.`t1` where (`<subquery2>`.`max(a)` = `test`.`t1`.`a`)
select * from t1 where a in (select max(a) from t1 group by b);
a b
0 0
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drop table t1,t0;
set histogram_size=@save_histogram_size; set histogram_size=@save_histogram_size;
set optimizer_use_condition_selectivity=@save_optimizer_use_condition_selectivity; set optimizer_use_condition_selectivity=@save_optimizer_use_condition_selectivity;
set use_stat_tables=@save_use_stat_tables; set use_stat_tables=@save_use_stat_tables;

70
mysql-test/r/selectivity_innodb.result
View File

@ -359,13 +359,13 @@ and o_orderkey = l_orderkey
group by c_name, c_custkey, o_orderkey, o_orderdate, o_totalprice group by c_name, c_custkey, o_orderkey, o_orderdate, o_totalprice
order by o_totalprice desc, o_orderdate; order by o_totalprice desc, o_orderdate;
id select_type table type possible_keys key key_len ref rows filtered Extra id select_type table type possible_keys key key_len ref rows filtered Extra
1 PRIMARY <subquery2> ALL distinct_key NULL NULL NULL 6005 0.00 Using temporary; Using filesort 1 PRIMARY orders ALL PRIMARY,i_o_custkey NULL NULL NULL 1500 100.00 Using where; Using temporary; Using filesort
1 PRIMARY orders eq_ref PRIMARY,i_o_custkey PRIMARY 4 <subquery2>.l_orderkey 1 100.00 Using where 1 PRIMARY <subquery2> eq_ref distinct_key distinct_key 4 dbt3_s001.orders.o_orderkey 1 100.00
1 PRIMARY customer eq_ref PRIMARY PRIMARY 4 dbt3_s001.orders.o_custkey 1 100.00 1 PRIMARY customer eq_ref PRIMARY PRIMARY 4 dbt3_s001.orders.o_custkey 1 100.00
1 PRIMARY lineitem ref PRIMARY,i_l_orderkey,i_l_orderkey_quantity PRIMARY 4 <subquery2>.l_orderkey 4 100.00 1 PRIMARY lineitem ref PRIMARY,i_l_orderkey,i_l_orderkey_quantity i_l_orderkey_quantity 4 dbt3_s001.orders.o_orderkey 4 100.00 Using index
2 MATERIALIZED lineitem index NULL PRIMARY 8 NULL 6005 100.00 2 MATERIALIZED lineitem index NULL PRIMARY 8 NULL 6005 100.00
Warnings: Warnings:
Note 1003 select `dbt3_s001`.`customer`.`c_name` AS `c_name`,`dbt3_s001`.`customer`.`c_custkey` AS `c_custkey`,`dbt3_s001`.`orders`.`o_orderkey` AS `o_orderkey`,`dbt3_s001`.`orders`.`o_orderDATE` AS `o_orderdate`,`dbt3_s001`.`orders`.`o_totalprice` AS `o_totalprice`,sum(`dbt3_s001`.`lineitem`.`l_quantity`) AS `sum(l_quantity)` from <materialize> (select `dbt3_s001`.`lineitem`.`l_orderkey` from `dbt3_s001`.`lineitem` group by `dbt3_s001`.`lineitem`.`l_orderkey` having (sum(`dbt3_s001`.`lineitem`.`l_quantity`) > 250)) join `dbt3_s001`.`customer` join `dbt3_s001`.`orders` join `dbt3_s001`.`lineitem` where ((`dbt3_s001`.`customer`.`c_custkey` = `dbt3_s001`.`orders`.`o_custkey`) and (`dbt3_s001`.`orders`.`o_orderkey` = `<subquery2>`.`l_orderkey`) and (`dbt3_s001`.`lineitem`.`l_orderkey` = `<subquery2>`.`l_orderkey`)) group by `dbt3_s001`.`customer`.`c_name`,`dbt3_s001`.`customer`.`c_custkey`,`dbt3_s001`.`orders`.`o_orderkey`,`dbt3_s001`.`orders`.`o_orderDATE`,`dbt3_s001`.`orders`.`o_totalprice` order by `dbt3_s001`.`orders`.`o_totalprice` desc,`dbt3_s001`.`orders`.`o_orderDATE` Note 1003 select `dbt3_s001`.`customer`.`c_name` AS `c_name`,`dbt3_s001`.`customer`.`c_custkey` AS `c_custkey`,`dbt3_s001`.`orders`.`o_orderkey` AS `o_orderkey`,`dbt3_s001`.`orders`.`o_orderDATE` AS `o_orderdate`,`dbt3_s001`.`orders`.`o_totalprice` AS `o_totalprice`,sum(`dbt3_s001`.`lineitem`.`l_quantity`) AS `sum(l_quantity)` from <materialize> (select `dbt3_s001`.`lineitem`.`l_orderkey` from `dbt3_s001`.`lineitem` group by `dbt3_s001`.`lineitem`.`l_orderkey` having (sum(`dbt3_s001`.`lineitem`.`l_quantity`) > 250)) join `dbt3_s001`.`customer` join `dbt3_s001`.`orders` join `dbt3_s001`.`lineitem` where ((`dbt3_s001`.`customer`.`c_custkey` = `dbt3_s001`.`orders`.`o_custkey`) and (`<subquery2>`.`l_orderkey` = `dbt3_s001`.`orders`.`o_orderkey`) and (`dbt3_s001`.`lineitem`.`l_orderkey` = `dbt3_s001`.`orders`.`o_orderkey`)) group by `dbt3_s001`.`customer`.`c_name`,`dbt3_s001`.`customer`.`c_custkey`,`dbt3_s001`.`orders`.`o_orderkey`,`dbt3_s001`.`orders`.`o_orderDATE`,`dbt3_s001`.`orders`.`o_totalprice` order by `dbt3_s001`.`orders`.`o_totalprice` desc,`dbt3_s001`.`orders`.`o_orderDATE`
select select
c_name, c_custkey, o_orderkey, o_orderdate, o_totalprice, sum(l_quantity) c_name, c_custkey, o_orderkey, o_orderdate, o_totalprice, sum(l_quantity)
from customer, orders, lineitem from customer, orders, lineitem
@ -1539,6 +1539,68 @@ t
10:00:00 10:00:00
11:00:00 11:00:00
DROP TABLE t1; DROP TABLE t1;
#
# MDEV-16374: filtered shows 0 for materilization scan for a semi join, which makes optimizer
# always pick materialization scan over materialization lookup
#
create table t0(a int);
insert into t0 values (0),(1),(2),(3),(4),(5),(6),(7),(8),(9);
create table t1 (a int, b int);
insert into t1 values (0,0),(1,1),(2,2),(3,3),(4,4),(5,5),(6,6),(7,7),(8,8),(9,9),(10,10),
(11,11),(12,12),(13,13),(14,14),(15,15);
set @@optimizer_use_condition_selectivity=2;
explain extended select * from t1 where a in (select max(a) from t1 group by b);
id select_type table type possible_keys key key_len ref rows filtered Extra
1 PRIMARY t1 ALL NULL NULL NULL NULL 16 100.00 Using where
1 PRIMARY <subquery2> eq_ref distinct_key distinct_key 4 test.t1.a 1 100.00
2 MATERIALIZED t1 ALL NULL NULL NULL NULL 16 100.00 Using temporary
Warnings:
Note 1003 select `test`.`t1`.`a` AS `a`,`test`.`t1`.`b` AS `b` from <materialize> (select max(`test`.`t1`.`a`) from `test`.`t1` group by `test`.`t1`.`b`) join `test`.`t1` where (`<subquery2>`.`max(a)` = `test`.`t1`.`a`)
select * from t1 where a in (select max(a) from t1 group by b);
a b
0 0
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set @@optimizer_use_condition_selectivity=1;
explain extended select * from t1 where a in (select max(a) from t1 group by b);
id select_type table type possible_keys key key_len ref rows filtered Extra
1 PRIMARY t1 ALL NULL NULL NULL NULL 16 100.00 Using where
1 PRIMARY <subquery2> eq_ref distinct_key distinct_key 4 test.t1.a 1 100.00
2 MATERIALIZED t1 ALL NULL NULL NULL NULL 16 100.00 Using temporary
Warnings:
Note 1003 select `test`.`t1`.`a` AS `a`,`test`.`t1`.`b` AS `b` from <materialize> (select max(`test`.`t1`.`a`) from `test`.`t1` group by `test`.`t1`.`b`) join `test`.`t1` where (`<subquery2>`.`max(a)` = `test`.`t1`.`a`)
select * from t1 where a in (select max(a) from t1 group by b);
a b
0 0
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drop table t1,t0;
set histogram_size=@save_histogram_size; set histogram_size=@save_histogram_size;
set optimizer_use_condition_selectivity=@save_optimizer_use_condition_selectivity; set optimizer_use_condition_selectivity=@save_optimizer_use_condition_selectivity;
set use_stat_tables=@save_use_stat_tables; set use_stat_tables=@save_use_stat_tables;

6
mysql-test/r/subselect_sj_nonmerged.result
View File

@ -77,9 +77,9 @@ explain select * from t4 where
t4.a in (select max(t2.a) from t1, t2 group by t2.b) and t4.a in (select max(t2.a) from t1, t2 group by t2.b) and
t4.b in (select max(t2.a) from t1, t2 group by t2.b); t4.b in (select max(t2.a) from t1, t2 group by t2.b);
id select_type table type possible_keys key key_len ref rows Extra id select_type table type possible_keys key key_len ref rows Extra
1 PRIMARY <subquery3> ALL distinct_key NULL NULL NULL 5 1 PRIMARY <subquery2> ALL distinct_key NULL NULL NULL 5
1 PRIMARY <subquery2> ALL distinct_key NULL NULL NULL 5 Using join buffer (flat, BNL join) 1 PRIMARY t4 ref a a 5 <subquery2>.max(t2.a) 12 Using index condition
1 PRIMARY t4 ref a a 10 <subquery2>.max(t2.a),<subquery3>.max(t2.a) 12 1 PRIMARY <subquery3> eq_ref distinct_key distinct_key 4 test.t4.b 1
3 MATERIALIZED t2 ALL NULL NULL NULL NULL 5 Using temporary 3 MATERIALIZED t2 ALL NULL NULL NULL NULL 5 Using temporary
3 MATERIALIZED t1 ALL NULL NULL NULL NULL 10 Using join buffer (flat, BNL join) 3 MATERIALIZED t1 ALL NULL NULL NULL NULL 10 Using join buffer (flat, BNL join)
2 MATERIALIZED t2 ALL NULL NULL NULL NULL 5 Using temporary 2 MATERIALIZED t2 ALL NULL NULL NULL NULL 5 Using temporary

18
mysql-test/t/selectivity.test
View File

@ -1043,6 +1043,24 @@ SELECT * FROM (SELECT t FROM t1 WHERE d IS NULL) sq;
DROP TABLE t1; DROP TABLE t1;
--echo #
--echo # MDEV-16374: filtered shows 0 for materilization scan for a semi join, which makes optimizer
--echo # always pick materialization scan over materialization lookup
--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, b int);
insert into t1 values (0,0),(1,1),(2,2),(3,3),(4,4),(5,5),(6,6),(7,7),(8,8),(9,9),(10,10),
(11,11),(12,12),(13,13),(14,14),(15,15);
set @@optimizer_use_condition_selectivity=2;
explain extended select * from t1 where a in (select max(a) from t1 group by b);
select * from t1 where a in (select max(a) from t1 group by b);
set @@optimizer_use_condition_selectivity=1;
explain extended select * from t1 where a in (select max(a) from t1 group by b);
select * from t1 where a in (select max(a) from t1 group by b);
drop table t1,t0;
set histogram_size=@save_histogram_size; set histogram_size=@save_histogram_size;
set optimizer_use_condition_selectivity=@save_optimizer_use_condition_selectivity; set optimizer_use_condition_selectivity=@save_optimizer_use_condition_selectivity;
set use_stat_tables=@save_use_stat_tables; set use_stat_tables=@save_use_stat_tables;

8
sql/table.cc
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@ -7099,7 +7099,15 @@ int TABLE_LIST::fetch_number_of_rows()
{ {
int error= 0; int error= 0;
if (jtbm_subselect) if (jtbm_subselect)
{
if (jtbm_subselect->is_jtbm_merged)
{
table->file->stats.records= jtbm_subselect->jtbm_record_count;
set_if_bigger(table->file->stats.records, 2);
table->used_stat_records= table->file->stats.records;
}
return 0; return 0;
}
if (is_materialized_derived() && !fill_me) if (is_materialized_derived() && !fill_me)
{ {