From 7afa5f1c5af3b78ff1db21c191e36258d6f478e7 Mon Sep 17 00:00:00 2001 From: "evgen@moonbone.local" <> Date: Wed, 7 Mar 2007 21:44:58 +0300 Subject: [PATCH] Bug#22331: Wrong WHERE in EXPLAIN EXTENDED when all expressions were optimized away. During optimization stage the WHERE conditions can be changed or even be removed at all if they know for sure to be true of false. Thus they aren't showed in the EXPLAIN EXTENDED which prints conditions after optimization. Now if all elements of an Item_cond were removed this Item_cond is substituted for an Item_int with the int value of the Item_cond. If there were conditions that were totally optimized away then values of the saved cond_value and having_value will be printed instead. --- mysql-test/r/explain.result | 29 +++++++++++++++++++++++++++++ mysql-test/r/func_test.result | 2 +- mysql-test/r/subselect.result | 16 ++++++++-------- mysql-test/t/explain.test | 14 ++++++++++++++ sql/sql_lex.cc | 1 + sql/sql_lex.h | 2 ++ sql/sql_select.cc | 23 ++++++++++++++++++----- sql/sql_select.h | 2 +- 8 files changed, 74 insertions(+), 15 deletions(-) diff --git a/mysql-test/r/explain.result b/mysql-test/r/explain.result index 3bd7b2ccc15..221a8695f60 100644 --- a/mysql-test/r/explain.result +++ b/mysql-test/r/explain.result @@ -57,3 +57,32 @@ select 3 into @v1; explain select 3 into @v1; id select_type table type possible_keys key key_len ref rows Extra 1 SIMPLE NULL NULL NULL NULL NULL NULL NULL No tables used +create table t1(f1 int, f2 int); +insert into t1 values (1,1); +create view v1 as select * from t1 where f1=1; +explain extended select * from v1 where f2=1; +id select_type table type possible_keys key key_len ref rows Extra +1 SIMPLE t1 system NULL NULL NULL NULL 1 +Warnings: +Note 1003 select `test`.`t1`.`f1` AS `f1`,`test`.`t1`.`f2` AS `f2` from `test`.`t1` where 1 +explain extended select * from t1 where 0; +id select_type table type possible_keys key key_len ref rows Extra +1 SIMPLE NULL NULL NULL NULL NULL NULL NULL Impossible WHERE +Warnings: +Note 1003 select `test`.`t1`.`f1` AS `f1`,`test`.`t1`.`f2` AS `f2` from `test`.`t1` where 0 +explain extended select * from t1 where 1; +id select_type table type possible_keys key key_len ref rows Extra +1 SIMPLE t1 system NULL NULL NULL NULL 1 +Warnings: +Note 1003 select `test`.`t1`.`f1` AS `f1`,`test`.`t1`.`f2` AS `f2` from `test`.`t1` where 1 +explain extended select * from t1 having 0; +id select_type table type possible_keys key key_len ref rows Extra +1 SIMPLE NULL NULL NULL NULL NULL NULL NULL Impossible HAVING +Warnings: +Note 1003 select `test`.`t1`.`f1` AS `f1`,`test`.`t1`.`f2` AS `f2` from `test`.`t1` having 0 +explain extended select * from t1 having 1; +id select_type table type possible_keys key key_len ref rows Extra +1 SIMPLE t1 system NULL NULL NULL NULL 1 +Warnings: +Note 1003 select `test`.`t1`.`f1` AS `f1`,`test`.`t1`.`f2` AS `f2` from `test`.`t1` having 1 +drop table t1; diff --git a/mysql-test/r/func_test.result b/mysql-test/r/func_test.result index 43832bdbccc..c3fbdb3b3bf 100644 --- a/mysql-test/r/func_test.result +++ b/mysql-test/r/func_test.result @@ -79,7 +79,7 @@ explain extended select * from t1 where 1 xor 1; id select_type table type possible_keys key key_len ref rows Extra 1 SIMPLE NULL NULL NULL NULL NULL NULL NULL Impossible WHERE Warnings: -Note 1003 select `test`.`t1`.`a` AS `a` from `test`.`t1` +Note 1003 select `test`.`t1`.`a` AS `a` from `test`.`t1` where 0 select - a from t1; - a -1 diff --git a/mysql-test/r/subselect.result b/mysql-test/r/subselect.result index 06f8c019265..1f29497f662 100644 --- a/mysql-test/r/subselect.result +++ b/mysql-test/r/subselect.result @@ -421,7 +421,7 @@ id select_type table type possible_keys key key_len ref rows Extra 3 UNION NULL NULL NULL NULL NULL NULL NULL No tables used NULL UNION RESULT ALL NULL NULL NULL NULL NULL Warnings: -Note 1003 select 1 AS `1` from `test`.`t1` +Note 1003 select 1 AS `1` from `test`.`t1` where 1 drop table t1; CREATE TABLE `t1` ( `numeropost` mediumint(8) unsigned NOT NULL auto_increment, @@ -1180,7 +1180,7 @@ id select_type table type possible_keys key key_len ref rows Extra 1 PRIMARY NULL NULL NULL NULL NULL NULL NULL No tables used 2 DEPENDENT SUBQUERY NULL NULL NULL NULL NULL NULL NULL Impossible WHERE Warnings: -Note 1003 select (0,(select 1 AS `Not_used` from `test`.`t1` `a`)) AS `0 IN (SELECT 1 FROM t1 a)` +Note 1003 select (0,(select 1 AS `Not_used` from `test`.`t1` `a` where 0)) AS `0 IN (SELECT 1 FROM t1 a)` INSERT INTO t1 (pseudo) VALUES ('test1'); SELECT 0 IN (SELECT 1 FROM t1 a); 0 IN (SELECT 1 FROM t1 a) @@ -1190,7 +1190,7 @@ id select_type table type possible_keys key key_len ref rows Extra 1 PRIMARY NULL NULL NULL NULL NULL NULL NULL No tables used 2 DEPENDENT SUBQUERY NULL NULL NULL NULL NULL NULL NULL Impossible WHERE Warnings: -Note 1003 select (0,(select 1 AS `Not_used` from `test`.`t1` `a`)) AS `0 IN (SELECT 1 FROM t1 a)` +Note 1003 select (0,(select 1 AS `Not_used` from `test`.`t1` `a` where 0)) AS `0 IN (SELECT 1 FROM t1 a)` drop table t1; CREATE TABLE `t1` ( `i` int(11) NOT NULL default '0', @@ -1532,7 +1532,7 @@ 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 t2 system NULL NULL NULL NULL 0 const row not found Warnings: -Note 1003 select `test`.`t3`.`a` AS `a` from `test`.`t3` +Note 1003 select `test`.`t3`.`a` AS `a` from `test`.`t3` where 0 select * from t3 where NULL >= any (select b from t2 group by 1); a explain extended select * from t3 where NULL >= any (select b from t2 group by 1); @@ -1540,7 +1540,7 @@ 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 t2 system NULL NULL NULL NULL 0 const row not found Warnings: -Note 1003 select `test`.`t3`.`a` AS `a` from `test`.`t3` +Note 1003 select `test`.`t3`.`a` AS `a` from `test`.`t3` where 0 select * from t3 where NULL >= some (select b from t2); a explain extended select * from t3 where NULL >= some (select b from t2); @@ -1548,7 +1548,7 @@ 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 t2 system NULL NULL NULL NULL 0 const row not found Warnings: -Note 1003 select `test`.`t3`.`a` AS `a` from `test`.`t3` +Note 1003 select `test`.`t3`.`a` AS `a` from `test`.`t3` where 0 select * from t3 where NULL >= some (select b from t2 group by 1); a explain extended select * from t3 where NULL >= some (select b from t2 group by 1); @@ -1556,7 +1556,7 @@ 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 t2 system NULL NULL NULL NULL 0 const row not found Warnings: -Note 1003 select `test`.`t3`.`a` AS `a` from `test`.`t3` +Note 1003 select `test`.`t3`.`a` AS `a` from `test`.`t3` where 0 insert into t2 values (2,2), (2,1), (3,3), (3,1); select * from t3 where a > all (select max(b) from t2 group by a); a @@ -1618,7 +1618,7 @@ id select_type table type possible_keys key key_len ref rows Extra 3 UNION t1 system NULL NULL NULL NULL 1 NULL UNION RESULT ALL NULL NULL NULL NULL NULL Warnings: -Note 1003 select `test`.`t1`.`s1` AS `s1` from `test`.`t1` +Note 1003 select `test`.`t1`.`s1` AS `s1` from `test`.`t1` where 1 drop table t1; CREATE TABLE t1 (number char(11) NOT NULL default '') ENGINE=MyISAM CHARSET=latin1; INSERT INTO t1 VALUES ('69294728265'),('18621828126'),('89356874041'),('95895001874'); diff --git a/mysql-test/t/explain.test b/mysql-test/t/explain.test index efce0cdf3b5..85bbbfea154 100644 --- a/mysql-test/t/explain.test +++ b/mysql-test/t/explain.test @@ -51,4 +51,18 @@ set names latin1; select 3 into @v1; explain select 3 into @v1; +# +# Bug#22331: Wrong WHERE in EXPLAIN EXTENDED when all expressions were +# optimized away. +# +create table t1(f1 int, f2 int); +insert into t1 values (1,1); +create view v1 as select * from t1 where f1=1; +explain extended select * from v1 where f2=1; +explain extended select * from t1 where 0; +explain extended select * from t1 where 1; +explain extended select * from t1 having 0; +explain extended select * from t1 having 1; +drop table t1; + # End of 5.0 tests. diff --git a/sql/sql_lex.cc b/sql/sql_lex.cc index ce76c35b33c..86590e10535 100644 --- a/sql/sql_lex.cc +++ b/sql/sql_lex.cc @@ -1192,6 +1192,7 @@ void st_select_lex::init_select() is_correlated= 0; cur_pos_in_select_list= UNDEF_POS; non_agg_fields.empty(); + cond_value= having_value= Item::COND_UNDEF; } /* diff --git a/sql/sql_lex.h b/sql/sql_lex.h index ae2b0d30a9c..4400c94e7f5 100644 --- a/sql/sql_lex.h +++ b/sql/sql_lex.h @@ -487,6 +487,8 @@ public: Item *where, *having; /* WHERE & HAVING clauses */ Item *prep_where; /* saved WHERE clause for prepared statement processing */ Item *prep_having;/* saved HAVING clause for prepared statement processing */ + /* Saved values of the WHERE and HAVING clauses*/ + Item::cond_result cond_value, having_value; /* point on lex in which it was created, used in view subquery detection */ st_lex *parent_lex; enum olap_type olap; diff --git a/sql/sql_select.cc b/sql/sql_select.cc index e7b18201a0a..6adb26ade29 100644 --- a/sql/sql_select.cc +++ b/sql/sql_select.cc @@ -681,7 +681,6 @@ JOIN::optimize() } { - Item::cond_result having_value; having= optimize_cond(this, having, join_list, &having_value); if (thd->net.report_error) { @@ -689,6 +688,10 @@ JOIN::optimize() DBUG_PRINT("error",("Error from optimize_cond")); DBUG_RETURN(1); } + if (select_lex->where) + select_lex->cond_value= cond_value; + if (select_lex->having) + select_lex->having_value= having_value; if (cond_value == Item::COND_FALSE || having_value == Item::COND_FALSE || (!unit->select_limit_cnt && !(select_options & OPTION_FOUND_ROWS))) @@ -829,6 +832,7 @@ JOIN::optimize() conds->update_used_tables(); DBUG_EXECUTE("where", print_where(conds, "after substitute_best_equal");); } + /* Permorm the the optimization on fields evaluation mentioned above for all on expressions. @@ -7535,6 +7539,9 @@ static COND* substitute_for_best_equal_field(COND *cond, break; } } + if (!((Item_cond*)cond)->argument_list()->elements) + cond= new Item_int(cond->val_bool()); + } else if (cond->type() == Item::FUNC_ITEM && ((Item_cond*) cond)->functype() == Item_func::MULT_EQUAL_FUNC) @@ -15259,10 +15266,13 @@ void st_select_lex::print(THD *thd, String *str) Item *cur_where= where; if (join) cur_where= join->conds; - if (cur_where) + if (cur_where || cond_value != Item::COND_UNDEF) { str->append(STRING_WITH_LEN(" where ")); - cur_where->print(str); + if (cur_where) + cur_where->print(str); + else + str->append(cond_value != Item::COND_FALSE ? "1" : "0"); } // group by & olap @@ -15288,10 +15298,13 @@ void st_select_lex::print(THD *thd, String *str) if (join) cur_having= join->having; - if (cur_having) + if (cur_having || having_value != Item::COND_UNDEF) { str->append(STRING_WITH_LEN(" having ")); - cur_having->print(str); + if (cur_having) + cur_having->print(str); + else + str->append(having_value != Item::COND_FALSE ? "1" : "0"); } if (order_list.elements) diff --git a/sql/sql_select.h b/sql/sql_select.h index a17d7fcb362..27ca633fdb5 100644 --- a/sql/sql_select.h +++ b/sql/sql_select.h @@ -292,7 +292,7 @@ public: bool need_tmp, hidden_group_fields; DYNAMIC_ARRAY keyuse; - Item::cond_result cond_value; + Item::cond_result cond_value, having_value; List all_fields; // to store all fields that used in query //Above list changed to use temporary table List tmp_all_fields1, tmp_all_fields2, tmp_all_fields3;