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MDEV-30360 Assertion `cond_selectivity <= 1.000000001' failed in ...

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The problem was that make_join_select() called test_quick_select() outside
of best_access_path(). This could use indexes that where not taken into
account before and this caused changes to selectivity and 'records_out'.

Fixed by updating records_out if test_quick_select() was called.
This commit is contained in:
Monty 2023-01-09 17:48:06 +02:00
parent 0a7d291756
commit 65da564530
4 changed files with 54 additions and 0 deletions
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13
mysql-test/main/selectivity.result
View File

@ -1998,3 +1998,16 @@ id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE B ref a a 5 const 1 1 SIMPLE B ref a a 5 const 1
set optimizer_use_condition_selectivity= @save_optimizer_use_condition_selectivity; set optimizer_use_condition_selectivity= @save_optimizer_use_condition_selectivity;
drop table t1,t2; drop table t1,t2;
#
# MDEV-30360 Assertion `cond_selectivity <= 1.000000001' failed in get_range_limit_read_cost
# with LIMIT .. OFFSET
#
CREATE TABLE t1 (a INT, b VARCHAR(1), KEY(b), KEY(a)) engine=myisam;
INSERT INTO t1 VALUES
(3,'a'),(2,'g'),(5,'v'),(9,'n'),(6,'u'),
(7,'s'),(0,'z'),(3,'z'),(NULL,'m'),(6,'r');
CREATE TABLE t2 (pk INT PRIMARY KEY);
INSERT INTO t2 VALUES (1),(2);
SELECT STRAIGHT_JOIN pk FROM t1 JOIN t2 ON a = pk WHERE b >= 'A' ORDER BY t2.pk LIMIT 8 OFFSET 1;
pk
DROP TABLE t1, t2;

17
mysql-test/main/selectivity.test
View File

@ -1359,3 +1359,20 @@ set optimizer_use_condition_selectivity=2;
EXPLAIN SELECT * FROM t1 A, t1 B WHERE A.a = B.a and A.id = 65; EXPLAIN SELECT * FROM t1 A, t1 B WHERE A.a = B.a and A.id = 65;
set optimizer_use_condition_selectivity= @save_optimizer_use_condition_selectivity; set optimizer_use_condition_selectivity= @save_optimizer_use_condition_selectivity;
drop table t1,t2; drop table t1,t2;
--echo #
--echo # MDEV-30360 Assertion `cond_selectivity <= 1.000000001' failed in get_range_limit_read_cost
--echo # with LIMIT .. OFFSET
--echo #
CREATE TABLE t1 (a INT, b VARCHAR(1), KEY(b), KEY(a)) engine=myisam;
INSERT INTO t1 VALUES
(3,'a'),(2,'g'),(5,'v'),(9,'n'),(6,'u'),
(7,'s'),(0,'z'),(3,'z'),(NULL,'m'),(6,'r');
CREATE TABLE t2 (pk INT PRIMARY KEY);
INSERT INTO t2 VALUES (1),(2);
SELECT STRAIGHT_JOIN pk FROM t1 JOIN t2 ON a = pk WHERE b >= 'A' ORDER BY t2.pk LIMIT 8 OFFSET 1;
DROP TABLE t1, t2;

13
mysql-test/main/selectivity_innodb.result
View File

@ -2005,6 +2005,19 @@ id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE B ref a a 5 const 1 Using index 1 SIMPLE B ref a a 5 const 1 Using index
set optimizer_use_condition_selectivity= @save_optimizer_use_condition_selectivity; set optimizer_use_condition_selectivity= @save_optimizer_use_condition_selectivity;
drop table t1,t2; drop table t1,t2;
#
# MDEV-30360 Assertion `cond_selectivity <= 1.000000001' failed in get_range_limit_read_cost
# with LIMIT .. OFFSET
#
CREATE TABLE t1 (a INT, b VARCHAR(1), KEY(b), KEY(a)) engine=myisam;
INSERT INTO t1 VALUES
(3,'a'),(2,'g'),(5,'v'),(9,'n'),(6,'u'),
(7,'s'),(0,'z'),(3,'z'),(NULL,'m'),(6,'r');
CREATE TABLE t2 (pk INT PRIMARY KEY);
INSERT INTO t2 VALUES (1),(2);
SELECT STRAIGHT_JOIN pk FROM t1 JOIN t2 ON a = pk WHERE b >= 'A' ORDER BY t2.pk LIMIT 8 OFFSET 1;
pk
DROP TABLE t1, t2;
set optimizer_switch=@save_optimizer_switch_for_selectivity_test; set optimizer_switch=@save_optimizer_switch_for_selectivity_test;
set @tmp_ust= @@use_stat_tables; set @tmp_ust= @@use_stat_tables;
set @tmp_oucs= @@optimizer_use_condition_selectivity; set @tmp_oucs= @@optimizer_use_condition_selectivity;

11
sql/sql_select.cc
View File

@ -13434,6 +13434,17 @@ make_join_select(JOIN *join,SQL_SELECT *select,COND *cond)
set_if_smaller(join->best_positions[i].records_out, set_if_smaller(join->best_positions[i].records_out,
join->best_positions[i].records_read); join->best_positions[i].records_read);
} }
else
{
/*
sel->head->opt_range_condition_rows may have been updated to a smaller number than
before by a call to test_quick_select. This can happen even if the range optimizer
decided to not use the range (sel->quick was not set).
*/
set_if_smaller(join->best_positions[i].records_out,
rows2double(sel->head->opt_range_condition_rows));
}
} }
else else
{ {