diff --git a/mysql-test/r/join_nested.result b/mysql-test/r/join_nested.result index 6b7293d46bcdab81caa11ce6446b68ed58bd911b..faad969fcd1dc6cd359a88f4179fba95eab7bd3a 100644 --- a/mysql-test/r/join_nested.result +++ b/mysql-test/r/join_nested.result @@ -960,7 +960,7 @@ id select_type table type possible_keys key key_len ref rows Extra 1 SIMPLE t2 ALL NULL NULL NULL NULL 3 Using where 1 SIMPLE t3 ALL NULL NULL NULL NULL 2 Using where 1 SIMPLE t4 ref idx_b idx_b 5 test.t2.b 2 Using where -1 SIMPLE t5 ALL NULL NULL NULL NULL 3 Using where +1 SIMPLE t5 ALL idx_b NULL NULL NULL 3 Using where 1 SIMPLE t7 ALL NULL NULL NULL NULL 2 Using where 1 SIMPLE t6 ALL NULL NULL NULL NULL 3 Using where 1 SIMPLE t8 ALL NULL NULL NULL NULL 2 Using where @@ -1009,7 +1009,7 @@ id select_type table type possible_keys key key_len ref rows Extra 1 SIMPLE t2 ALL NULL NULL NULL NULL 3 Using where 1 SIMPLE t3 ALL NULL NULL NULL NULL 2 Using where 1 SIMPLE t4 ref idx_b idx_b 5 test.t2.b 2 Using where -1 SIMPLE t5 ALL NULL NULL NULL NULL 3 Using where +1 SIMPLE t5 ALL idx_b NULL NULL NULL 3 Using where 1 SIMPLE t7 ALL NULL NULL NULL NULL 2 Using where 1 SIMPLE t6 ALL NULL NULL NULL NULL 3 Using where 1 SIMPLE t8 ref idx_b idx_b 5 test.t5.b 2 Using where @@ -1059,7 +1059,7 @@ id select_type table type possible_keys key key_len ref rows Extra 1 SIMPLE t2 ALL NULL NULL NULL NULL 3 Using where 1 SIMPLE t3 ALL NULL NULL NULL NULL 2 Using where 1 SIMPLE t4 ref idx_b idx_b 5 test.t2.b 2 Using where -1 SIMPLE t5 ALL NULL NULL NULL NULL 3 Using where +1 SIMPLE t5 ALL idx_b NULL NULL NULL 3 Using where 1 SIMPLE t7 ALL NULL NULL NULL NULL 2 Using where 1 SIMPLE t6 ALL NULL NULL NULL NULL 3 Using where 1 SIMPLE t8 ref idx_b idx_b 5 test.t5.b 2 Using where @@ -1467,3 +1467,17 @@ id select_type table type possible_keys key key_len ref rows Extra 1 SIMPLE t6 ref a a 5 test.t4.b X 1 SIMPLE t5 ref a a 5 test.t3.b X drop table t0, t1, t2, t3, t4, t5, t6, t7; +create table t1 (a int); +insert into t1 values (0),(1),(2),(3),(4),(5),(6),(7),(8),(9); +create table t2 (a int, filler char(100), key(a)); +insert into t2 select A.a + 10*B.a, '' from t1 A, t1 B; +create table t3 like t2; +insert into t3 select * from t2; +explain select * from t1 left join +(t2 left join t3 on (t2.a = t3.a)) +on (t1.a = t2.a); +id select_type table type possible_keys key key_len ref rows Extra +1 SIMPLE t1 ALL NULL NULL NULL NULL 10 +1 SIMPLE t2 ref a a 5 test.t1.a 1 +1 SIMPLE t3 ref a a 5 test.t2.a 1 +drop table t1, t2, t3; diff --git a/mysql-test/t/join_nested.test b/mysql-test/t/join_nested.test index 9f23e2d0e2f1b03db27e8b8c8c84a92a869534fc..145edded486ae7a5f681e040a0ffe5f65f5db3e5 100644 --- a/mysql-test/t/join_nested.test +++ b/mysql-test/t/join_nested.test @@ -900,3 +900,17 @@ explain select * from t2 left join join t5 on t5.a=t3.b) on t3.a=t2.b; drop table t0, t1, t2, t3, t4, t5, t6, t7; + +# BUG#16393 +create table t1 (a int); +insert into t1 values (0),(1),(2),(3),(4),(5),(6),(7),(8),(9); +create table t2 (a int, filler char(100), key(a)); +insert into t2 select A.a + 10*B.a, '' from t1 A, t1 B; +create table t3 like t2; +insert into t3 select * from t2; + +explain select * from t1 left join + (t2 left join t3 on (t2.a = t3.a)) + on (t1.a = t2.a); +drop table t1, t2, t3; + diff --git a/sql/sql_select.cc b/sql/sql_select.cc index ab58fda8dea8d305f04d0dcc4b819fbf634ff32b..be255d1f790b2b22d18400720a0115710bdfad6f 100644 --- a/sql/sql_select.cc +++ b/sql/sql_select.cc @@ -2918,6 +2918,56 @@ sort_keyuse(KEYUSE *a,KEYUSE *b) } +/* + Add to KEY_FIELD array all 'ref' access candidates within nested join + + SYNPOSIS + add_key_fields_for_nj() + nested_join_table IN Nested join pseudo-table to process + end INOUT End of the key field array + and_level INOUT And-level + + DESCRIPTION + This function populates KEY_FIELD array with entries generated from the + ON condition of the given nested join, and does the same for nested joins + contained within this nested join. + + NOTES + We can add accesses to the tables that are direct children of this nested + join (1), and are not inner tables w.r.t their neighbours (2). + + Example for #1 (outer brackets pair denotes nested join this function is + invoked for): + ... LEFT JOIN (t1 LEFT JOIN (t2 ... ) ) ON cond + Example for #2: + ... LEFT JOIN (t1 LEFT JOIN t2 ) ON cond + In examples 1-2 for condition cond, we can add 'ref' access candidates to + t1 only. + Example #3: + ... LEFT JOIN (t1, t2 LEFT JOIN t3 ON inner_cond) ON cond + Here we can add 'ref' access candidates for t1 and t2, but not for t3. +*/ + +static void add_key_fields_for_nj(TABLE_LIST *nested_join_table, + KEY_FIELD **end, uint *and_level) +{ + List_iterator<TABLE_LIST> li(nested_join_table->nested_join->join_list); + table_map tables= 0; + TABLE_LIST *table; + DBUG_ASSERT(nested_join_table->nested_join); + + while ((table= li++)) + { + if (table->nested_join) + add_key_fields_for_nj(table, end, and_level); + else + if (!table->on_expr) + tables |= table->table->map; + } + add_key_fields(end, and_level, nested_join_table->on_expr, tables); +} + + /* Update keyuse array with all possible keys we can use to fetch rows @@ -2982,23 +3032,21 @@ update_ref_and_keys(THD *thd, DYNAMIC_ARRAY *keyuse,JOIN_TAB *join_tab, into account as well. */ if (*join_tab[i].on_expr_ref) - { add_key_fields(&end,&and_level,*join_tab[i].on_expr_ref, join_tab[i].table->map); - } - else + } + + /* Process ON conditions for the nested joins */ + { + List_iterator<TABLE_LIST> li(*join_tab->join->join_list); + TABLE_LIST *table; + while ((table= li++)) { - TABLE_LIST *tab= join_tab[i].table->pos_in_table_list; - TABLE_LIST *embedding= tab->embedding; - if (embedding) - { - NESTED_JOIN *nested_join= embedding->nested_join; - if (nested_join->join_list.head() == tab) - add_key_fields(&end, &and_level, embedding->on_expr, - nested_join->used_tables); - } + if (table->nested_join) + add_key_fields_for_nj(table, &end, &and_level); } } + /* fill keyuse with found key parts */ for ( ; field != end ; field++) add_key_part(keyuse,field);