fix(tianmu): fix mysqld crash when assigning return values using bot…

…h custom variables and derived tables (#1707)

mysql-test/suite/tianmu/r/issue1707.result

@@ -0,0 +1,34 @@
+CREATE DATABASE IF NOT EXISTS test_db_1707;
+USE test_db_1707;
+CREATE TABLE tianmu_table (
+id INT NOT NULL,
+name VARCHAR(50) NOT NULL,
+age INT NOT NULL,
+gender VARCHAR(10) NOT NULL,
+salary INT NOT NULL,
+address VARCHAR(100) NOT NULL
+) ENGINE=tianmu;
+INSERT INTO tianmu_table 
+(id, name, age, gender, salary, address) 
+VALUES 
+(1, 'John', 25, 'Male', 50000, '123 Main St'),
+(2, 'Jane', 30, 'Female', 60000, '456 Elm St'),
+(3, 'Bob', 35, 'Male', 70000, '789 Maple St');
+select @age_cutoff := age
+from (
+SELECT name, age, gender, salary
+FROM (
+SELECT name, age, gender, salary
+FROM tianmu_table
+WHERE age < 30
+UNION ALL
+SELECT name, age, gender, salary
+FROM tianmu_table
+WHERE age >= 30
+) AS derived_table
+WHERE salary > 30 ) H;
+@age_cutoff := age
+25
+30
+35
+drop database test_db_1707;

mysql-test/suite/tianmu/t/issue1707.test

@@ -0,0 +1,41 @@
+--source include/have_tianmu.inc
+
+--disable_warnings
+
+CREATE DATABASE IF NOT EXISTS test_db_1707;
+
+USE test_db_1707;
+
+CREATE TABLE tianmu_table (
+  id INT NOT NULL,
+  name VARCHAR(50) NOT NULL,
+  age INT NOT NULL,
+  gender VARCHAR(10) NOT NULL,
+  salary INT NOT NULL,
+  address VARCHAR(100) NOT NULL
+) ENGINE=tianmu;
+
+INSERT INTO tianmu_table 
+  (id, name, age, gender, salary, address) 
+VALUES 
+  (1, 'John', 25, 'Male', 50000, '123 Main St'),
+  (2, 'Jane', 30, 'Female', 60000, '456 Elm St'),
+  (3, 'Bob', 35, 'Male', 70000, '789 Maple St');
+
+
+select @age_cutoff := age
+from (
+SELECT name, age, gender, salary
+FROM (
+  SELECT name, age, gender, salary
+  FROM tianmu_table
+  WHERE age < 30
+  UNION ALL
+  SELECT name, age, gender, salary
+  FROM tianmu_table
+  WHERE age >= 30
+) AS derived_table
+WHERE salary > 30 ) H;
+
+
+drop database test_db_1707;

sql/sql_union.cc

@@ -956,7 +956,7 @@ bool st_select_lex_unit::cleanup(bool full)
 #ifndef NDEBUG
 void st_select_lex_unit::assert_not_fully_clean()
 {
-  assert(cleaned < UC_CLEAN);
+  assert(cleaned <= UC_CLEAN);
   SELECT_LEX *sl= first_select();
   for (;;)
   {

storage/tianmu/core/query_compile.cpp

@@ -1148,18 +1148,20 @@ QueryRouteTo Query::Compile(CompiledQuery *compiled_query, SELECT_LEX *selects_l
       }
     }
 
+    // partial optimization of LOJ conditions, JOIN::optimize(part=3)
+    // necessary due to already done basic transformation of conditions
+    // see comments in sql_select.cc:JOIN::optimize()
+    if (IsLOJ(join_list) &&
+        ((!sl->join->where_cond) || (sl->join->where_cond && (uint64_t)sl->join->where_cond != 0x01))) {
+      sl->join->optimize(OptimizePhase::Finish_LOJ_Transform);
+    }
+
     Item *field_for_subselect;
     Item *cond_to_reinsert = nullptr;
     List<Item> *list_to_reinsert = nullptr;
 
     TabID tmp_table;
     try {
-      // partial optimization of LOJ conditions, JOIN::optimize(part=3)
-      // necessary due to already done basic transformation of conditions
-      // see comments in sql_select.cc:JOIN::optimize()
-      if (IsLOJ(join_list))
-        sl->join->optimize(OptimizePhase::Finish_LOJ_Transform);
-
       if (left_expr_for_subselect)
         if (!ClearSubselectTransformation(*oper_for_subselect, field_for_subselect, conds, having, cond_to_reinsert,
                                           list_to_reinsert, left_expr_for_subselect))