revision-id: 85b0a9cdf92bddbb4084024c9eb851466ecb8fce (mariadb-10.4.27-70-g85b0a9c) parent(s): b05218e08f45a17f46d1b73cbb9dcb2969dc04cd author: Igor Babaev committer: Igor Babaev timestamp: 2023-02-02 22:38:32 -0800 message: MDEV-30538 Plans for SELECT and multi-table UPDATE/DELETE unexpectedly differ This patch allowed transformation of EXISTS subqueries into equivalent IN predicands at the top level of WHERE conditions for multi-table UPDATE and DELETE statements. There was no reason to prohibit the transformation for such statements. The transformation provides more opportunities of using semi-join optimizations. Approved by Oleksandr Byelkin <sanja@mariadb.com> --- mysql-test/main/multi_update.result | 120 +++++++++++++++++++++++++++++++ mysql-test/main/multi_update.test | 70 ++++++++++++++++++ mysql-test/main/update_use_source.result | 12 ++-- sql/item_subselect.cc | 4 +- 4 files changed, 201 insertions(+), 5 deletions(-) diff --git a/mysql-test/main/multi_update.result b/mysql-test/main/multi_update.result index 61e04c3..d6cf9ba 100644 --- a/mysql-test/main/multi_update.result +++ b/mysql-test/main/multi_update.result @@ -1251,3 +1251,123 @@ EXPLAIN } } DROP TABLES t1, t2; +# End of 10.3 tests +# +# MDEV-28538: multi-table UPDATE/DELETE with possible exists-to-in +# +create table t1 (c1 int, c2 int, c3 int, index idx(c2)); +insert into t1 values +(1,1,1),(3,2,2),(1,3,3), +(2,1,4),(2,2,5),(4,3,6), +(2,4,7),(2,5,8); +create table t2 (c1 int, c2 int, c3 int, index idx(c2)); +insert into t2 values +(1,7,1),(1,8,2),(1,3,3), +(2,1,4),(2,2,5),(2,3,6), +(2,4,7),(2,5,8); +create table t3 (c1 int, c2 int, c3 int, index idx(c2)); +insert into t3 values +(1,1,1),(1,2,2),(1,3,3), +(2,1,4),(2,2,5),(2,3,6), +(2,4,7),(2,5,8); +insert into t3 select c1+1, c2+2, c3 from t3; +insert into t3 select c1, c2+2, c3 from t3; +analyze table t1,t2,t3 persistent for all; +Table Op Msg_type Msg_text +test.t1 analyze status Engine-independent statistics collected +test.t1 analyze status OK +test.t2 analyze status Engine-independent statistics collected +test.t2 analyze status OK +test.t3 analyze status Engine-independent statistics collected +test.t3 analyze status OK +explain select * from t1,t3 +where t1.c2 = t3.c2 and +t1.c1 > 1 and +exists (select 'X' from t2 where t2.c1 = t1.c1 and t2.c2 > 4); +id select_type table type possible_keys key key_len ref rows Extra +1 PRIMARY t1 ALL idx NULL NULL NULL 8 Using where +1 PRIMARY <subquery2> eq_ref distinct_key distinct_key 4 func 1 +1 PRIMARY t3 ref idx idx 5 test.t1.c2 3 +2 MATERIALIZED t2 range idx idx 5 NULL 3 Using index condition; Using where +explain delete from t1 using t1,t3 +where t1.c2 = t3.c2 and +t1.c1 > 1 and +exists (select 'X' from t2 where t2.c1 = t1.c1 and t2.c2 > 4); +id select_type table type possible_keys key key_len ref rows Extra +1 PRIMARY t1 ALL idx NULL NULL NULL 8 Using where +1 PRIMARY <subquery2> eq_ref distinct_key distinct_key 4 func 1 +1 PRIMARY t3 ref idx idx 5 test.t1.c2 3 Using index +2 MATERIALIZED t2 range idx idx 5 NULL 3 Using where +explain update t1,t3 set t1.c1 = t1.c1+10 +where t1.c2 = t3.c2 and +t1.c1 > 1 and +exists (select 'X' from t2 where t2.c1 = t1.c1 and t2.c2 > 4); +id select_type table type possible_keys key key_len ref rows Extra +1 PRIMARY t1 ALL idx NULL NULL NULL 8 Using where +1 PRIMARY <subquery2> eq_ref distinct_key distinct_key 4 func 1 +1 PRIMARY t3 ref idx idx 5 test.t1.c2 3 Using index +2 MATERIALIZED t2 range idx idx 5 NULL 3 Using where +create table t as select * from t1; +select * from t1,t3 +where t1.c2 = t3.c2 and +t1.c1 > 1 and +exists (select 'X' from t2 where t2.c1 = t1.c1 and t2.c2 > 4); +c1 c2 c3 c1 c2 c3 +2 1 4 1 1 1 +2 1 4 2 1 4 +2 2 5 1 2 2 +2 2 5 2 2 5 +2 4 7 2 4 7 +2 4 7 2 4 2 +2 4 7 3 4 5 +2 4 7 1 4 2 +2 4 7 2 4 5 +2 5 8 2 5 8 +2 5 8 2 5 3 +2 5 8 3 5 6 +2 5 8 1 5 3 +2 5 8 2 5 6 +2 5 8 2 5 1 +2 5 8 3 5 4 +select * from t1; +c1 c2 c3 +1 1 1 +3 2 2 +1 3 3 +2 1 4 +2 2 5 +4 3 6 +2 4 7 +2 5 8 +delete from t1 using t1,t3 +where t1.c2 = t3.c2 and +t1.c1 > 1 and +exists (select 'X' from t2 where t2.c1 = t1.c1 and t2.c2 > 4); +select * from t1; +c1 c2 c3 +1 1 1 +3 2 2 +1 3 3 +4 3 6 +truncate table t1; +insert into t1 select * from t; +analyze table t1 persistent for all; +Table Op Msg_type Msg_text +test.t1 analyze status Engine-independent statistics collected +test.t1 analyze status Table is already up to date +update t1,t3 set t1.c1 = t1.c1+10 +where t1.c2 = t3.c2 and +t1.c1 > 1 and +exists (select 'X' from t2 where t2.c1 = t1.c1 and t2.c2 > 4); +select * from t1; +c1 c2 c3 +1 1 1 +3 2 2 +1 3 3 +12 1 4 +12 2 5 +4 3 6 +12 4 7 +12 5 8 +drop table t1,t2,t3,t; +# End of 10.4 tests diff --git a/mysql-test/main/multi_update.test b/mysql-test/main/multi_update.test index 54c6491..48e6250 100644 --- a/mysql-test/main/multi_update.test +++ b/mysql-test/main/multi_update.test @@ -1130,3 +1130,73 @@ EXPLAIN FORMAT=JSON UPDATE t2 JOIN t1 USING(a) SET t2.part=2 WHERE t2.part=1 AND EXPLAIN FORMAT=JSON UPDATE t2 JOIN t1 USING(a) SET t2.part=3 WHERE t2.part=2 AND t1.part=2; DROP TABLES t1, t2; + +--echo # End of 10.3 tests + +--echo # +--echo # MDEV-28538: multi-table UPDATE/DELETE with possible exists-to-in +--echo # + +create table t1 (c1 int, c2 int, c3 int, index idx(c2)); +insert into t1 values +(1,1,1),(3,2,2),(1,3,3), +(2,1,4),(2,2,5),(4,3,6), +(2,4,7),(2,5,8); + +create table t2 (c1 int, c2 int, c3 int, index idx(c2)); +insert into t2 values +(1,7,1),(1,8,2),(1,3,3), +(2,1,4),(2,2,5),(2,3,6), +(2,4,7),(2,5,8); + +create table t3 (c1 int, c2 int, c3 int, index idx(c2)); +insert into t3 values +(1,1,1),(1,2,2),(1,3,3), +(2,1,4),(2,2,5),(2,3,6), +(2,4,7),(2,5,8); +insert into t3 select c1+1, c2+2, c3 from t3; +insert into t3 select c1, c2+2, c3 from t3; + +analyze table t1,t2,t3 persistent for all; + +let $c= + t1.c2 = t3.c2 and + t1.c1 > 1 and + exists (select 'X' from t2 where t2.c1 = t1.c1 and t2.c2 > 4); + +let $q1= +select * from t1,t3 +where $c; + +eval explain $q1; + +let $q2= +delete from t1 using t1,t3 +where $c; + +eval explain $q2; + +let $q3= +update t1,t3 set t1.c1 = t1.c1+10 +where $c; + +eval explain $q3; + +create table t as select * from t1; + +eval $q1; +select * from t1; + +eval $q2; +select * from t1; + +truncate table t1; +insert into t1 select * from t; +analyze table t1 persistent for all; + +eval $q3; +select * from t1; + +drop table t1,t2,t3,t; + +--echo # End of 10.4 tests diff --git a/mysql-test/main/update_use_source.result b/mysql-test/main/update_use_source.result index 9e43b54..5778767 100644 --- a/mysql-test/main/update_use_source.result +++ b/mysql-test/main/update_use_source.result @@ -76,7 +76,8 @@ rollback; explain update t1 set c1=0 where exists (select 'X' from t1 a where a.c2 = t1.c2) and c2 > 3; id select_type table type possible_keys key key_len ref rows Extra 1 PRIMARY t1 ALL NULL NULL NULL NULL 8 Using where -2 DEPENDENT SUBQUERY a ALL NULL NULL NULL NULL 8 Using where +1 PRIMARY <subquery2> eq_ref distinct_key distinct_key 4 func 1 +2 MATERIALIZED a ALL NULL NULL NULL NULL 8 start transaction; update t1 set c1=c1+10 where exists (select 'X' from t1 a where a.c2 = t1.c2) and c2 >= 3; affected rows: 4 @@ -317,7 +318,8 @@ rollback; explain update t1 set c1=0 where exists (select 'X' from t1 a where a.c2 = t1.c2) and c2 > 3; id select_type table type possible_keys key key_len ref rows Extra 1 PRIMARY t1 range t1_c2 t1_c2 5 NULL 2 Using where -2 DEPENDENT SUBQUERY a ref t1_c2 t1_c2 5 test.t1.c2 4 Using index +1 PRIMARY <subquery2> eq_ref distinct_key distinct_key 4 func 1 +2 MATERIALIZED a range t1_c2 t1_c2 5 NULL 2 Using where; Using index start transaction; update t1 set c1=c1+10 where exists (select 'X' from t1 a where a.c2 = t1.c2) and c2 >= 3; affected rows: 4 @@ -558,7 +560,8 @@ rollback; explain update t1 set c1=0 where exists (select 'X' from t1 a where a.c2 = t1.c2) and c2 > 3; id select_type table type possible_keys key key_len ref rows Extra 1 PRIMARY t1 range t1_c2 t1_c2 5 NULL 2 Using where -2 DEPENDENT SUBQUERY a ref t1_c2 t1_c2 5 test.t1.c2 1 Using index +1 PRIMARY <subquery2> eq_ref distinct_key distinct_key 4 func 1 +2 MATERIALIZED a range t1_c2 t1_c2 5 NULL 2 Using where; Using index start transaction; update t1 set c1=c1+10 where exists (select 'X' from t1 a where a.c2 = t1.c2) and c2 >= 3; affected rows: 4 @@ -800,7 +803,8 @@ rollback; explain update t1 set c1=0 where exists (select 'X' from t1 a where a.c2 = t1.c2) and c2 > 3; id select_type table type possible_keys key key_len ref rows Extra 1 PRIMARY t1 range t1_c2 t1_c2 5 NULL 2 Using where -2 DEPENDENT SUBQUERY a ref t1_c2 t1_c2 5 test.t1.c2 1 Using index +1 PRIMARY <subquery2> eq_ref distinct_key distinct_key 4 func 1 +2 MATERIALIZED a range t1_c2 t1_c2 5 NULL 2 Using where; Using index start transaction; update t1 set c1=c1+10 where exists (select 'X' from t1 a where a.c2 = t1.c2) and c2 >= 3; affected rows: 4 diff --git a/sql/item_subselect.cc b/sql/item_subselect.cc index 461bd9f..1454073 100644 --- a/sql/item_subselect.cc +++ b/sql/item_subselect.cc @@ -2825,7 +2825,9 @@ bool Item_exists_subselect::select_prepare_to_be_in() bool trans_res= FALSE; DBUG_ENTER("Item_exists_subselect::select_prepare_to_be_in"); if (!optimizer && - thd->lex->sql_command == SQLCOM_SELECT && + (thd->lex->sql_command == SQLCOM_SELECT || + thd->lex->sql_command == SQLCOM_UPDATE_MULTI || + thd->lex->sql_command == SQLCOM_DELETE_MULTI) && !unit->first_select()->is_part_of_union() && optimizer_flag(thd, OPTIMIZER_SWITCH_EXISTS_TO_IN) && (is_top_level_item() ||