Bug#35889583: Server fails when we execute set of queries Bug#35996409: Failure in Query_expression::is_set_operation() Bug#36404149: Failing the server

roylyseng · roylyseng · commit 77fca51c4c51 · 2025-03-14T10:58:44.000+01:00
Problem is that we attempt to inspect a query expression object that
has been abandoned due to condition elimination. The problem is with
equality operations that are transformed into semi-join conditions,
where we store the left and right parts of the equality in
sj_inner_exprs and sj_outer_exprs.

The fix is to remove the references in the semi-join expression arrays
when removing the corresponding equality condition. A dive within all
join nests of the query block is necessary, due to the fact that we
may have seen multiple transformations that add join nests so far.

Also had to add some code that was developed for the fix
of bug#35710378. This code was not originally needed for 8.0,
but without it there would be several tests using semi-join that would
change plans.

Change-Id: Ida1bc4c1d586733330b8bd63a3f1f51ac094b96f
diff --git a/mysql-test/r/group_by_fd_no_prot.result b/mysql-test/r/group_by_fd_no_prot.result
@@ -2221,7 +2221,7 @@ id	select_type	table	partitions	type	possible_keys	key	key_len	ref	rows	filtered
 2	DEPENDENT SUBQUERY	t3	NULL	index	NULL	b	15	NULL	1	100.00	Using where; Not exists; Using index; Using join buffer (hash join)
 Warnings:
 Note	1276	Field or reference 'test.t1.b' of SELECT #3 was resolved in SELECT #1
-Note	1003	/* select#1 */ select (/* select#2 */ select 2 from `test`.`t2` anti join (`test`.`t3`) on((1 = 1)) where true) AS `col` from `test`.`t1` group by `test`.`t1`.`a`
+Note	1003	/* select#1 */ select (/* select#2 */ select 2 from `test`.`t2` anti join (`test`.`t3`) on(true) where true) AS `col` from `test`.`t1` group by `test`.`t1`.`a`
 explain select (select 2 from t2 where exists(select 1 from t3 where t1.b)) as col from t1 group by t1.a;
 ERROR 42000: Expression #1 of SELECT list is not in GROUP BY clause and contains nonaggregated column 'test.t1.b' which is not functionally dependent on columns in GROUP BY clause; this is incompatible with sql_mode=only_full_group_by
 explain select (select 2 from t2 where not exists(select 1 from t3 where t1.b)) as col from t1 group by t1.a;
diff --git a/mysql-test/r/group_by_fd_ps_prot.result b/mysql-test/r/group_by_fd_ps_prot.result
@@ -1577,7 +1577,7 @@ id	select_type	table	partitions	type	possible_keys	key	key_len	ref	rows	filtered
 2	DEPENDENT SUBQUERY	t3	NULL	index	NULL	b	15	NULL	1	100.00	Using where; Not exists; Using index; Using join buffer (hash join)
 Warnings:
 Note	1276	Field or reference 'test.t1.b' of SELECT #3 was resolved in SELECT #1
-Note	1003	/* select#1 */ select (/* select#2 */ select 2 from `test`.`t2` anti join (`test`.`t3`) on((1 = 1)) where true) AS `col` from `test`.`t1` group by `test`.`t1`.`a`
+Note	1003	/* select#1 */ select (/* select#2 */ select 2 from `test`.`t2` anti join (`test`.`t3`) on(true) where true) AS `col` from `test`.`t1` group by `test`.`t1`.`a`
 explain select (select 2 from t2 where exists(select 1 from t3 where t1.b)) as col from t1 group by t1.a;
 ERROR 42000: Expression #1 of SELECT list is not in GROUP BY clause and contains nonaggregated column 'test.t1.b' which is not functionally dependent on columns in GROUP BY clause; this is incompatible with sql_mode=only_full_group_by
 explain select (select 2 from t2 where not exists(select 1 from t3 where t1.b)) as col from t1 group by t1.a;
diff --git a/mysql-test/r/subquery_sj_all.result b/mysql-test/r/subquery_sj_all.result
@@ -7774,7 +7774,7 @@ WHERE 1 IN(SELECT 1
 FROM t4)));
 id	select_type	table	partitions	type	possible_keys	key	key_len	ref	rows	filtered	Extra
 1	SIMPLE	t1	NULL	ALL	NULL	NULL	NULL	NULL	9	100.00	NULL
-1	SIMPLE	<subquery2>	NULL	const	<auto_distinct_key>	<auto_distinct_key>	4	const	1	100.00	NULL
+1	SIMPLE	<subquery2>	NULL	const	<auto_distinct_key>	<auto_distinct_key>	8	const	1	100.00	NULL
 2	MATERIALIZED	t2	NULL	ALL	NULL	NULL	NULL	NULL	9	100.00	NULL
 2	MATERIALIZED	t3	NULL	ALL	NULL	NULL	NULL	NULL	9	100.00	Using join buffer (hash join)
 2	MATERIALIZED	t4	NULL	ALL	NULL	NULL	NULL	NULL	9	100.00	Using join buffer (hash join)
diff --git a/mysql-test/r/subquery_sj_all_bka.result b/mysql-test/r/subquery_sj_all_bka.result
@@ -7776,7 +7776,7 @@ WHERE 1 IN(SELECT 1
 FROM t4)));
 id	select_type	table	partitions	type	possible_keys	key	key_len	ref	rows	filtered	Extra
 1	SIMPLE	t1	NULL	ALL	NULL	NULL	NULL	NULL	9	100.00	NULL
-1	SIMPLE	<subquery2>	NULL	const	<auto_distinct_key>	<auto_distinct_key>	4	const	1	100.00	NULL
+1	SIMPLE	<subquery2>	NULL	const	<auto_distinct_key>	<auto_distinct_key>	8	const	1	100.00	NULL
 2	MATERIALIZED	t2	NULL	ALL	NULL	NULL	NULL	NULL	9	100.00	NULL
 2	MATERIALIZED	t3	NULL	ALL	NULL	NULL	NULL	NULL	9	100.00	Using join buffer (hash join)
 2	MATERIALIZED	t4	NULL	ALL	NULL	NULL	NULL	NULL	9	100.00	Using join buffer (hash join)
diff --git a/mysql-test/r/subquery_sj_all_bka_nobnl.result b/mysql-test/r/subquery_sj_all_bka_nobnl.result
@@ -7774,7 +7774,7 @@ WHERE 1 IN(SELECT 1
 FROM t4)));
 id	select_type	table	partitions	type	possible_keys	key	key_len	ref	rows	filtered	Extra
 1	SIMPLE	t1	NULL	ALL	NULL	NULL	NULL	NULL	9	100.00	NULL
-1	SIMPLE	<subquery2>	NULL	const	<auto_distinct_key>	<auto_distinct_key>	4	const	1	100.00	NULL
+1	SIMPLE	<subquery2>	NULL	const	<auto_distinct_key>	<auto_distinct_key>	8	const	1	100.00	NULL
 2	MATERIALIZED	t2	NULL	ALL	NULL	NULL	NULL	NULL	9	100.00	NULL
 2	MATERIALIZED	t3	NULL	ALL	NULL	NULL	NULL	NULL	9	100.00	NULL
 2	MATERIALIZED	t4	NULL	ALL	NULL	NULL	NULL	NULL	9	100.00	NULL
diff --git a/mysql-test/r/subquery_sj_mat.result b/mysql-test/r/subquery_sj_mat.result
@@ -7977,7 +7977,7 @@ WHERE 1 IN(SELECT 1
 FROM t3));
 id	select_type	table	partitions	type	possible_keys	key	key_len	ref	rows	filtered	Extra
 1	SIMPLE	t1	NULL	ALL	NULL	NULL	NULL	NULL	2	100.00	NULL
-1	SIMPLE	<subquery2>	NULL	const	<auto_distinct_key>	<auto_distinct_key>	4	const	1	100.00	NULL
+1	SIMPLE	<subquery2>	NULL	const	<auto_distinct_key>	<auto_distinct_key>	8	const	1	100.00	NULL
 2	MATERIALIZED	t2	NULL	ALL	NULL	NULL	NULL	NULL	2	100.00	NULL
 2	MATERIALIZED	t3	NULL	ALL	NULL	NULL	NULL	NULL	2	100.00	Using join buffer (hash join)
 Warnings:
@@ -8016,7 +8016,7 @@ WHERE 1 IN(SELECT 1
 FROM t4)));
 id	select_type	table	partitions	type	possible_keys	key	key_len	ref	rows	filtered	Extra
 1	SIMPLE	t1	NULL	ALL	NULL	NULL	NULL	NULL	9	100.00	NULL
-1	SIMPLE	<subquery2>	NULL	const	<auto_distinct_key>	<auto_distinct_key>	4	const	1	100.00	NULL
+1	SIMPLE	<subquery2>	NULL	const	<auto_distinct_key>	<auto_distinct_key>	8	const	1	100.00	NULL
 2	MATERIALIZED	t2	NULL	ALL	NULL	NULL	NULL	NULL	9	100.00	NULL
 2	MATERIALIZED	t3	NULL	ALL	NULL	NULL	NULL	NULL	9	100.00	Using join buffer (hash join)
 2	MATERIALIZED	t4	NULL	ALL	NULL	NULL	NULL	NULL	9	100.00	Using join buffer (hash join)
@@ -13188,9 +13188,8 @@ Table	Op	Msg_type	Msg_text
 test.t1	analyze	status	OK
 EXPLAIN SELECT 1 FROM t1 WHERE EXISTS(SELECT 1) IN (SELECT 1 FROM t1);
 id	select_type	table	partitions	type	possible_keys	key	key_len	ref	rows	filtered	Extra
-1	PRIMARY	t1	NULL	ALL	NULL	NULL	NULL	NULL	1	100.00	NULL
-1	PRIMARY	<subquery3>	NULL	const	<auto_distinct_key>	<auto_distinct_key>	4	const	1	100.00	NULL
-3	MATERIALIZED	t1	NULL	ALL	NULL	NULL	NULL	NULL	1	100.00	NULL
+1	PRIMARY	t1	NULL	ALL	NULL	NULL	NULL	NULL	1	100.00	Start temporary
+1	PRIMARY	t1	NULL	ALL	NULL	NULL	NULL	NULL	1	100.00	End temporary; Using join buffer (hash join)
 2	SUBQUERY	NULL	NULL	NULL	NULL	NULL	NULL	NULL	NULL	NULL	No tables used
 Warnings:
 Note	1003	/* select#1 */ select 1 AS `1` from `test`.`t1` semi join (`test`.`t1`) where true
diff --git a/mysql-test/r/subquery_sj_mat_bka.result b/mysql-test/r/subquery_sj_mat_bka.result
@@ -7978,7 +7978,7 @@ WHERE 1 IN(SELECT 1
 FROM t3));
 id	select_type	table	partitions	type	possible_keys	key	key_len	ref	rows	filtered	Extra
 1	SIMPLE	t1	NULL	ALL	NULL	NULL	NULL	NULL	2	100.00	NULL
-1	SIMPLE	<subquery2>	NULL	const	<auto_distinct_key>	<auto_distinct_key>	4	const	1	100.00	NULL
+1	SIMPLE	<subquery2>	NULL	const	<auto_distinct_key>	<auto_distinct_key>	8	const	1	100.00	NULL
 2	MATERIALIZED	t2	NULL	ALL	NULL	NULL	NULL	NULL	2	100.00	NULL
 2	MATERIALIZED	t3	NULL	ALL	NULL	NULL	NULL	NULL	2	100.00	Using join buffer (hash join)
 Warnings:
@@ -8017,7 +8017,7 @@ WHERE 1 IN(SELECT 1
 FROM t4)));
 id	select_type	table	partitions	type	possible_keys	key	key_len	ref	rows	filtered	Extra
 1	SIMPLE	t1	NULL	ALL	NULL	NULL	NULL	NULL	9	100.00	NULL
-1	SIMPLE	<subquery2>	NULL	const	<auto_distinct_key>	<auto_distinct_key>	4	const	1	100.00	NULL
+1	SIMPLE	<subquery2>	NULL	const	<auto_distinct_key>	<auto_distinct_key>	8	const	1	100.00	NULL
 2	MATERIALIZED	t2	NULL	ALL	NULL	NULL	NULL	NULL	9	100.00	NULL
 2	MATERIALIZED	t3	NULL	ALL	NULL	NULL	NULL	NULL	9	100.00	Using join buffer (hash join)
 2	MATERIALIZED	t4	NULL	ALL	NULL	NULL	NULL	NULL	9	100.00	Using join buffer (hash join)
@@ -13189,9 +13189,8 @@ Table	Op	Msg_type	Msg_text
 test.t1	analyze	status	OK
 EXPLAIN SELECT 1 FROM t1 WHERE EXISTS(SELECT 1) IN (SELECT 1 FROM t1);
 id	select_type	table	partitions	type	possible_keys	key	key_len	ref	rows	filtered	Extra
-1	PRIMARY	t1	NULL	ALL	NULL	NULL	NULL	NULL	1	100.00	NULL
-1	PRIMARY	<subquery3>	NULL	const	<auto_distinct_key>	<auto_distinct_key>	4	const	1	100.00	NULL
-3	MATERIALIZED	t1	NULL	ALL	NULL	NULL	NULL	NULL	1	100.00	NULL
+1	PRIMARY	t1	NULL	ALL	NULL	NULL	NULL	NULL	1	100.00	Start temporary
+1	PRIMARY	t1	NULL	ALL	NULL	NULL	NULL	NULL	1	100.00	End temporary; Using join buffer (hash join)
 2	SUBQUERY	NULL	NULL	NULL	NULL	NULL	NULL	NULL	NULL	NULL	No tables used
 Warnings:
 Note	1003	/* select#1 */ select 1 AS `1` from `test`.`t1` semi join (`test`.`t1`) where true
diff --git a/mysql-test/r/subquery_sj_mat_bka_nobnl.result b/mysql-test/r/subquery_sj_mat_bka_nobnl.result
@@ -7977,7 +7977,7 @@ WHERE 1 IN(SELECT 1
 FROM t3));
 id	select_type	table	partitions	type	possible_keys	key	key_len	ref	rows	filtered	Extra
 1	SIMPLE	t1	NULL	ALL	NULL	NULL	NULL	NULL	2	100.00	NULL
-1	SIMPLE	<subquery2>	NULL	const	<auto_distinct_key>	<auto_distinct_key>	4	const	1	100.00	NULL
+1	SIMPLE	<subquery2>	NULL	const	<auto_distinct_key>	<auto_distinct_key>	8	const	1	100.00	NULL
 2	MATERIALIZED	t2	NULL	ALL	NULL	NULL	NULL	NULL	2	100.00	NULL
 2	MATERIALIZED	t3	NULL	ALL	NULL	NULL	NULL	NULL	2	100.00	NULL
 Warnings:
@@ -8016,7 +8016,7 @@ WHERE 1 IN(SELECT 1
 FROM t4)));
 id	select_type	table	partitions	type	possible_keys	key	key_len	ref	rows	filtered	Extra
 1	SIMPLE	t1	NULL	ALL	NULL	NULL	NULL	NULL	9	100.00	NULL
-1	SIMPLE	<subquery2>	NULL	const	<auto_distinct_key>	<auto_distinct_key>	4	const	1	100.00	NULL
+1	SIMPLE	<subquery2>	NULL	const	<auto_distinct_key>	<auto_distinct_key>	8	const	1	100.00	NULL
 2	MATERIALIZED	t2	NULL	ALL	NULL	NULL	NULL	NULL	9	100.00	NULL
 2	MATERIALIZED	t3	NULL	ALL	NULL	NULL	NULL	NULL	9	100.00	NULL
 2	MATERIALIZED	t4	NULL	ALL	NULL	NULL	NULL	NULL	9	100.00	NULL
@@ -13185,8 +13185,7 @@ test.t1	analyze	status	OK
 EXPLAIN SELECT 1 FROM t1 WHERE EXISTS(SELECT 1) IN (SELECT 1 FROM t1);
 id	select_type	table	partitions	type	possible_keys	key	key_len	ref	rows	filtered	Extra
 1	PRIMARY	t1	NULL	ALL	NULL	NULL	NULL	NULL	1	100.00	NULL
-1	PRIMARY	<subquery3>	NULL	const	<auto_distinct_key>	<auto_distinct_key>	4	const	1	100.00	NULL
-3	MATERIALIZED	t1	NULL	ALL	NULL	NULL	NULL	NULL	1	100.00	NULL
+1	PRIMARY	t1	NULL	ALL	NULL	NULL	NULL	NULL	1	100.00	Start temporary; End temporary
 2	SUBQUERY	NULL	NULL	NULL	NULL	NULL	NULL	NULL	NULL	NULL	No tables used
 Warnings:
 Note	1003	/* select#1 */ select 1 AS `1` from `test`.`t1` semi join (`test`.`t1`) where true
diff --git a/sql/item.h b/sql/item.h
@@ -2737,6 +2737,7 @@ class Item : public Parse_tree_node {
     Query_block *const m_root;
 
     friend class Item;
+    friend class Item_func_eq;
     friend class Item_sum;
     friend class Item_subselect;
     friend class Item_ref;
diff --git a/sql/item_cmpfunc.cc b/sql/item_cmpfunc.cc
@@ -2437,6 +2437,22 @@ void Item_in_optimizer::update_used_tables() {
   }
 }
 
+bool Item_func_eq::clean_up_after_removal(uchar *arg) {
+  Cleanup_after_removal_context *const ctx =
+      pointer_cast<Cleanup_after_removal_context *>(arg);
+
+  if (ctx->is_stopped(this)) return false;
+
+  if (reference_count() > 1) {
+    (void)decrement_ref_count();
+    ctx->stop_at(this);
+  }
+
+  ctx->get_root()->prune_sj_exprs(this, nullptr);
+
+  return false;
+}
+
 longlong Item_func_eq::val_int() {
   assert(fixed == 1);
   int value = cmp.compare();
diff --git a/sql/item_cmpfunc.h b/sql/item_cmpfunc.h
@@ -1057,6 +1057,7 @@ class Item_func_eq final : public Item_eq_base {
   Item *negated_item() override;
   bool equality_substitution_analyzer(uchar **) override { return true; }
   Item *equality_substitution_transformer(uchar *arg) override;
+  bool clean_up_after_removal(uchar *arg) override;
   bool gc_subst_analyzer(uchar **) override { return true; }
 
   float get_filtering_effect(THD *thd, table_map filter_for_table,
diff --git a/sql/sql_lex.h b/sql/sql_lex.h
@@ -1718,6 +1718,8 @@ class Query_block : public Query_term {
   */
   bool accept(Select_lex_visitor *visitor);
 
+  void prune_sj_exprs(Item_func_eq *item, mem_root_deque<Table_ref *> *nest);
+
   /**
     Cleanup this subtree (this Query_block and all nested Query_blockes and
     Query_expressions).
@@ -2208,7 +2210,7 @@ class Query_block : public Query_term {
   ///  Build semijoin condition for th query block
   bool build_sj_cond(THD *thd, NESTED_JOIN *nested_join,
                      Query_block *subq_query_block, table_map outer_tables_map,
-                     Item **sj_cond);
+                     Item **sj_cond, bool *simple_const);
   bool decorrelate_condition(Semijoin_decorrelation &sj_decor,
                              Table_ref *join_nest);
 
diff --git a/sql/sql_resolver.cc b/sql/sql_resolver.cc
