diff --git a/mysql-test/r/subselect.result b/mysql-test/r/subselect.result index 40f936fb3b4..69db0959373 100644 --- a/mysql-test/r/subselect.result +++ b/mysql-test/r/subselect.result @@ -7235,6 +7235,22 @@ a 5 SET @@optimizer_switch= @optimiser_switch_save; DROP TABLE t1, t2, t3; +# +# MDEV-16820: impossible where with inexpensive subquery +# +create table t1 (a int) engine=myisam; +insert into t1 values (3), (1), (7); +create table t2 (b int, index idx(b)); +insert into t2 values (2), (5), (3), (2); +explain select * from t1 where (select max(b) from t2) = 10; +id select_type table type possible_keys key key_len ref rows Extra +1 PRIMARY NULL NULL NULL NULL NULL NULL NULL Impossible WHERE +2 SUBQUERY NULL NULL NULL NULL NULL NULL NULL Select tables optimized away +explain select * from t1 where (select max(b) from t2) = 10 and t1.a > 3; +id select_type table type possible_keys key key_len ref rows Extra +1 PRIMARY NULL NULL NULL NULL NULL NULL NULL Impossible WHERE +2 SUBQUERY NULL NULL NULL NULL NULL NULL NULL Select tables optimized away +drop table t1,t2; End of 5.5 tests # End of 10.0 tests # diff --git a/mysql-test/r/subselect_no_exists_to_in.result b/mysql-test/r/subselect_no_exists_to_in.result index a23820820ef..ef3bf7ef692 100644 --- a/mysql-test/r/subselect_no_exists_to_in.result +++ b/mysql-test/r/subselect_no_exists_to_in.result @@ -7235,6 +7235,22 @@ a 5 SET @@optimizer_switch= @optimiser_switch_save; DROP TABLE t1, t2, t3; +# +# MDEV-16820: impossible where with inexpensive subquery +# +create table t1 (a int) engine=myisam; +insert into t1 values (3), (1), (7); +create table t2 (b int, index idx(b)); +insert into t2 values (2), (5), (3), (2); +explain select * from t1 where (select max(b) from t2) = 10; +id select_type table type possible_keys key key_len ref rows Extra +1 PRIMARY NULL NULL NULL NULL NULL NULL NULL Impossible WHERE +2 SUBQUERY NULL NULL NULL NULL NULL NULL NULL Select tables optimized away +explain select * from t1 where (select max(b) from t2) = 10 and t1.a > 3; +id select_type table type possible_keys key key_len ref rows Extra +1 PRIMARY NULL NULL NULL NULL NULL NULL NULL Impossible WHERE +2 SUBQUERY NULL NULL NULL NULL NULL NULL NULL Select tables optimized away +drop table t1,t2; End of 5.5 tests # End of 10.0 tests # diff --git a/mysql-test/r/subselect_no_mat.result b/mysql-test/r/subselect_no_mat.result index baa74307f89..703572e0ef8 100644 --- a/mysql-test/r/subselect_no_mat.result +++ b/mysql-test/r/subselect_no_mat.result @@ -7228,6 +7228,22 @@ a 5 SET @@optimizer_switch= @optimiser_switch_save; DROP TABLE t1, t2, t3; +# +# MDEV-16820: impossible where with inexpensive subquery +# +create table t1 (a int) engine=myisam; +insert into t1 values (3), (1), (7); +create table t2 (b int, index idx(b)); +insert into t2 values (2), (5), (3), (2); +explain select * from t1 where (select max(b) from t2) = 10; +id select_type table type possible_keys key key_len ref rows Extra +1 PRIMARY NULL NULL NULL NULL NULL NULL NULL Impossible WHERE +2 SUBQUERY NULL NULL NULL NULL NULL NULL NULL Select tables optimized away +explain select * from t1 where (select max(b) from t2) = 10 and t1.a > 3; +id select_type table type possible_keys key key_len ref rows Extra +1 PRIMARY NULL NULL NULL NULL NULL NULL NULL Impossible WHERE +2 SUBQUERY NULL NULL NULL NULL NULL NULL NULL Select tables optimized away +drop table t1,t2; End of 5.5 tests # End of 10.0 tests # diff --git a/mysql-test/r/subselect_no_opts.result b/mysql-test/r/subselect_no_opts.result index 039f2fe1a9e..39a098b754b 100644 --- a/mysql-test/r/subselect_no_opts.result +++ b/mysql-test/r/subselect_no_opts.result @@ -7226,6 +7226,22 @@ a 5 SET @@optimizer_switch= @optimiser_switch_save; DROP TABLE t1, t2, t3; +# +# MDEV-16820: impossible where with inexpensive subquery +# +create table t1 (a int) engine=myisam; +insert into t1 values (3), (1), (7); +create table t2 (b int, index idx(b)); +insert into t2 values (2), (5), (3), (2); +explain select * from t1 where (select max(b) from t2) = 10; +id select_type table type possible_keys key key_len ref rows Extra +1 PRIMARY NULL NULL NULL NULL NULL NULL NULL Impossible WHERE +2 SUBQUERY NULL NULL NULL NULL NULL NULL NULL Select tables optimized away +explain select * from t1 where (select max(b) from t2) = 10 and t1.a > 3; +id select_type table type possible_keys key key_len ref rows Extra +1 PRIMARY NULL NULL NULL NULL NULL NULL NULL Impossible WHERE +2 SUBQUERY NULL NULL NULL NULL NULL NULL NULL Select tables optimized away +drop table t1,t2; End of 5.5 tests # End of 10.0 tests # diff --git a/mysql-test/r/subselect_no_scache.result b/mysql-test/r/subselect_no_scache.result index 0ce77bbb376..b9a59bf3952 100644 --- a/mysql-test/r/subselect_no_scache.result +++ b/mysql-test/r/subselect_no_scache.result @@ -7241,6 +7241,22 @@ a 5 SET @@optimizer_switch= @optimiser_switch_save; DROP TABLE t1, t2, t3; +# +# MDEV-16820: impossible where with inexpensive subquery +# +create table t1 (a int) engine=myisam; +insert into t1 values (3), (1), (7); +create table t2 (b int, index idx(b)); +insert into t2 values (2), (5), (3), (2); +explain select * from t1 where (select max(b) from t2) = 10; +id select_type table type possible_keys key key_len ref rows Extra +1 PRIMARY NULL NULL NULL NULL NULL NULL NULL Impossible WHERE +2 SUBQUERY NULL NULL NULL NULL NULL NULL NULL Select tables optimized away +explain select * from t1 where (select max(b) from t2) = 10 and t1.a > 3; +id select_type table type possible_keys key key_len ref rows Extra +1 PRIMARY NULL NULL NULL NULL NULL NULL NULL Impossible WHERE +2 SUBQUERY NULL NULL NULL NULL NULL NULL NULL Select tables optimized away +drop table t1,t2; End of 5.5 tests # End of 10.0 tests # diff --git a/mysql-test/r/subselect_no_semijoin.result b/mysql-test/r/subselect_no_semijoin.result index 574e78122f1..f1df85fed6e 100644 --- a/mysql-test/r/subselect_no_semijoin.result +++ b/mysql-test/r/subselect_no_semijoin.result @@ -7226,6 +7226,22 @@ a 5 SET @@optimizer_switch= @optimiser_switch_save; DROP TABLE t1, t2, t3; +# +# MDEV-16820: impossible where with inexpensive subquery +# +create table t1 (a int) engine=myisam; +insert into t1 values (3), (1), (7); +create table t2 (b int, index idx(b)); +insert into t2 values (2), (5), (3), (2); +explain select * from t1 where (select max(b) from t2) = 10; +id select_type table type possible_keys key key_len ref rows Extra +1 PRIMARY NULL NULL NULL NULL NULL NULL NULL Impossible WHERE +2 SUBQUERY NULL NULL NULL NULL NULL NULL NULL Select tables optimized away +explain select * from t1 where (select max(b) from t2) = 10 and t1.a > 3; +id select_type table type possible_keys key key_len ref rows Extra +1 PRIMARY NULL NULL NULL NULL NULL NULL NULL Impossible WHERE +2 SUBQUERY NULL NULL NULL NULL NULL NULL NULL Select tables optimized away +drop table t1,t2; End of 5.5 tests # End of 10.0 tests # diff --git a/mysql-test/t/subselect.test b/mysql-test/t/subselect.test index 717871db61d..a4c4c21610e 100644 --- a/mysql-test/t/subselect.test +++ b/mysql-test/t/subselect.test @@ -6098,6 +6098,21 @@ and t1.a in (select `test`.`t3`.`c` from `test`.`t3`); SET @@optimizer_switch= @optimiser_switch_save; DROP TABLE t1, t2, t3; +--echo # +--echo # MDEV-16820: impossible where with inexpensive subquery +--echo # + +create table t1 (a int) engine=myisam; +insert into t1 values (3), (1), (7); + +create table t2 (b int, index idx(b)); +insert into t2 values (2), (5), (3), (2); + +explain select * from t1 where (select max(b) from t2) = 10; +explain select * from t1 where (select max(b) from t2) = 10 and t1.a > 3; + +drop table t1,t2; + --echo End of 5.5 tests --echo # End of 10.0 tests diff --git a/sql/item.h b/sql/item.h index 139ce40b25b..dcd773ffc59 100644 --- a/sql/item.h +++ b/sql/item.h @@ -1449,6 +1449,11 @@ public: virtual bool exists2in_processor(uchar *opt_arg) { return 0; } virtual bool find_selective_predicates_list_processor(uchar *opt_arg) { return 0; } + bool cleanup_is_expensive_cache_processor(uchar *arg) + { + is_expensive_cache= (int8)(-1); + return 0; + } /* To call bool function for all arguments */ struct bool_func_call_args diff --git a/sql/sql_select.cc b/sql/sql_select.cc index e3b725ce1f6..460a64e1a7a 100644 --- a/sql/sql_select.cc +++ b/sql/sql_select.cc @@ -1212,6 +1212,13 @@ JOIN::optimize_inner() if (optimize_constant_subqueries()) DBUG_RETURN(1); + if (conds && conds->has_subquery()) + (void) conds->walk(&Item::cleanup_is_expensive_cache_processor, + 0, (uchar*)0); + if (having && having->has_subquery()) + (void) having->walk(&Item::cleanup_is_expensive_cache_processor, + 0, (uchar*)0); + if (setup_jtbm_semi_joins(this, join_list, &conds)) DBUG_RETURN(1);