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MDEV-15087 Item_func::fix_fields:

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Assertion `used_tables_cache == 0' failed

This bug manifested itself when executing queries
over materialized derived tables /vies and with
conjunctive always true predicates containing
inexpensive single-row subqueries.
This bug disappeared after the patch mdev-15035
had been applied.
This commit is contained in:
Igor Babaev
2018-07-25 23:28:31 -07:00
parent 0f90728bc0
commit 3c141e319a
3 changed files with 51 additions and 7 deletions
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19
mysql-test/r/derived_cond_pushdown.result
View File

@@ -9808,3 +9808,22 @@ EXPLAIN
}
}
DROP TABLE t1;
#
# MDEV-15087: error from inexpensive subquery before check
# for condition pushdown into derived
#
CREATE TABLE t1 (i1 int, v1 varchar(1));
INSERT INTO t1 VALUES (7,'x');
CREATE TABLE t2 (i1 int);
INSERT INTO t2 VALUES (8);
CREATE TABLE t3 (i1 int ,v1 varchar(1), v2 varchar(1));
INSERT INTO t3 VALUES (4, 'v','v'),(62,'v','k'),(7, 'n', NULL);
SELECT 1
FROM (t1 AS a1
JOIN (((SELECT DISTINCT t3.*
FROM t3) AS a2
JOIN t1 ON (t1.v1 = a2.v2))) ON (t1.v1 = a2.v1))
WHERE (SELECT BIT_COUNT(t2.i1)
FROM (t2 JOIN t3)) IS NULL;
ERROR 21000: Subquery returns more than 1 row
DROP TABLE t1, t2, t3;

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

@@ -1840,3 +1840,28 @@ EVAL $query;
EVAL EXPLAIN FORMAT=JSON $query;
DROP TABLE t1;
--echo #
--echo # MDEV-15087: error from inexpensive subquery before check
--echo # for condition pushdown into derived
--echo #
CREATE TABLE t1 (i1 int, v1 varchar(1));
INSERT INTO t1 VALUES (7,'x');
CREATE TABLE t2 (i1 int);
INSERT INTO t2 VALUES (8);
CREATE TABLE t3 (i1 int ,v1 varchar(1), v2 varchar(1));
INSERT INTO t3 VALUES (4, 'v','v'),(62,'v','k'),(7, 'n', NULL);
--error ER_SUBQUERY_NO_1_ROW
SELECT 1
FROM (t1 AS a1
JOIN (((SELECT DISTINCT t3.*
FROM t3) AS a2
JOIN t1 ON (t1.v1 = a2.v2))) ON (t1.v1 = a2.v1))
WHERE (SELECT BIT_COUNT(t2.i1)
FROM (t2 JOIN t3)) IS NULL;
DROP TABLE t1, t2, t3;

14
sql/sql_select.cc
View File

@@ -1368,6 +1368,13 @@ JOIN::optimize_inner()
conds= optimize_cond(this, conds, join_list, FALSE,
&cond_value, &cond_equal, OPT_LINK_EQUAL_FIELDS);
if (thd->is_error())
{
error= 1;
DBUG_PRINT("error",("Error from optimize_cond"));
DBUG_RETURN(1);
}
if (thd->lex->sql_command == SQLCOM_SELECT &&
optimizer_flag(thd, OPTIMIZER_SWITCH_COND_PUSHDOWN_FOR_DERIVED))
{
@@ -1402,13 +1409,6 @@ JOIN::optimize_inner()
DBUG_RETURN(1);
}
if (thd->is_error())
{
error= 1;
DBUG_PRINT("error",("Error from optimize_cond"));
DBUG_RETURN(1);
}
{
having= optimize_cond(this, having, join_list, TRUE,
&having_value, &having_equal);