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Fixed bug mdev-11161.
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The flag TABLE_LIST::fill_me must be reset to false at the prepare
phase for any materialized derived table used in the executed query.
Otherwise if the optimizer decides to generate a key for such a table
it is generated only for the first execution of the query.
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igorbabaev committed Nov 12, 2016
1 parent 10aee66 commit 96b62b5
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83 changes: 83 additions & 0 deletions mysql-test/r/derived_view.result
Original file line number Diff line number Diff line change
Expand Up @@ -2496,5 +2496,88 @@ DROP TABLE t1,t2;
#
# end of 5.3 tests
#
#
# Bug mdev-11161: The second execution of prepared statement
# does not use generated key for materialized
# derived table / view
# (actually this is a 5.3 bug.)
#
create table t1 (
mat_id MEDIUMINT UNSIGNED NOT NULL AUTO_INCREMENT PRIMARY KEY,
matintnum CHAR(6) NOT NULL,
test MEDIUMINT UNSIGNED NULL
);
create table t2 (
mat_id MEDIUMINT UNSIGNED NOT NULL,
pla_id MEDIUMINT UNSIGNED NOT NULL
);
insert into t1 values
(NULL, 'a', 1), (NULL, 'b', 2), (NULL, 'c', 3), (NULL, 'd', 4),
(NULL, 'e', 5), (NULL, 'f', 6), (NULL, 'g', 7), (NULL, 'h', 8),
(NULL, 'i', 9);
insert into t2 values
(1, 100), (1, 101), (1, 102), (2, 100), (2, 103), (2, 104),
(3, 101), (3, 102), (3, 105);
explain
SELECT STRAIGHT_JOIN d.pla_id, m2.mat_id
FROM t1 m2
INNER JOIN
(SELECT mp.pla_id, MIN(m1.matintnum) AS matintnum
FROM t2 mp INNER JOIN t1 m1 ON mp.mat_id=m1.mat_id
GROUP BY mp.pla_id) d
ON d.matintnum=m2.matintnum;
id select_type table type possible_keys key key_len ref rows Extra
1 PRIMARY m2 ALL NULL NULL NULL NULL 9
1 PRIMARY <derived2> ref key0 key0 7 test.m2.matintnum 2
2 DERIVED mp ALL NULL NULL NULL NULL 9 Using temporary; Using filesort
2 DERIVED m1 eq_ref PRIMARY PRIMARY 3 test.mp.mat_id 1
prepare stmt1 from
"SELECT STRAIGHT_JOIN d.pla_id, m2.mat_id
FROM t1 m2
INNER JOIN
(SELECT mp.pla_id, MIN(m1.matintnum) AS matintnum
FROM t2 mp INNER JOIN t1 m1 ON mp.mat_id=m1.mat_id
GROUP BY mp.pla_id) d
ON d.matintnum=m2.matintnum";
flush status;
execute stmt1;
pla_id mat_id
102 1
101 1
100 1
104 2
103 2
105 3
show status like '%Handler_read%';
Variable_name Value
Handler_read_first 0
Handler_read_key 21
Handler_read_last 0
Handler_read_next 6
Handler_read_prev 0
Handler_read_rnd 6
Handler_read_rnd_deleted 0
Handler_read_rnd_next 27
flush status;
execute stmt1;
pla_id mat_id
102 1
101 1
100 1
104 2
103 2
105 3
show status like '%Handler_read%';
Variable_name Value
Handler_read_first 0
Handler_read_key 21
Handler_read_last 0
Handler_read_next 6
Handler_read_prev 0
Handler_read_rnd 6
Handler_read_rnd_deleted 0
Handler_read_rnd_next 27
deallocate prepare stmt1;
drop table t1,t2;
set optimizer_switch=@exit_optimizer_switch;
set join_cache_level=@exit_join_cache_level;
54 changes: 54 additions & 0 deletions mysql-test/t/derived_view.test
Original file line number Diff line number Diff line change
Expand Up @@ -1827,6 +1827,60 @@ DROP TABLE t1,t2;
--echo # end of 5.3 tests
--echo #

--echo #
--echo # Bug mdev-11161: The second execution of prepared statement
--echo # does not use generated key for materialized
--echo # derived table / view
--echo # (actually this is a 5.3 bug.)
--echo #

create table t1 (
mat_id MEDIUMINT UNSIGNED NOT NULL AUTO_INCREMENT PRIMARY KEY,
matintnum CHAR(6) NOT NULL,
test MEDIUMINT UNSIGNED NULL
);
create table t2 (
mat_id MEDIUMINT UNSIGNED NOT NULL,
pla_id MEDIUMINT UNSIGNED NOT NULL
);
insert into t1 values
(NULL, 'a', 1), (NULL, 'b', 2), (NULL, 'c', 3), (NULL, 'd', 4),
(NULL, 'e', 5), (NULL, 'f', 6), (NULL, 'g', 7), (NULL, 'h', 8),
(NULL, 'i', 9);
insert into t2 values
(1, 100), (1, 101), (1, 102), (2, 100), (2, 103), (2, 104),
(3, 101), (3, 102), (3, 105);

explain
SELECT STRAIGHT_JOIN d.pla_id, m2.mat_id
FROM t1 m2
INNER JOIN
(SELECT mp.pla_id, MIN(m1.matintnum) AS matintnum
FROM t2 mp INNER JOIN t1 m1 ON mp.mat_id=m1.mat_id
GROUP BY mp.pla_id) d
ON d.matintnum=m2.matintnum;

prepare stmt1 from
"SELECT STRAIGHT_JOIN d.pla_id, m2.mat_id
FROM t1 m2
INNER JOIN
(SELECT mp.pla_id, MIN(m1.matintnum) AS matintnum
FROM t2 mp INNER JOIN t1 m1 ON mp.mat_id=m1.mat_id
GROUP BY mp.pla_id) d
ON d.matintnum=m2.matintnum";

flush status;
execute stmt1;
show status like '%Handler_read%';

flush status;
execute stmt1;
show status like '%Handler_read%';

deallocate prepare stmt1;

drop table t1,t2;

# The following command must be the last one the file
set optimizer_switch=@exit_optimizer_switch;
set join_cache_level=@exit_join_cache_level;
2 changes: 2 additions & 0 deletions sql/sql_derived.cc
Original file line number Diff line number Diff line change
Expand Up @@ -651,6 +651,8 @@ bool mysql_derived_prepare(THD *thd, LEX *lex, TABLE_LIST *derived)

unit->derived= derived;

derived->fill_me= FALSE;

if (!(derived->derived_result= new select_union))
DBUG_RETURN(TRUE); // out of memory

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