MariaDB · Olernov · Dec 16, 2024 · Dec 17, 2024
diff --git a/mysql-test/main/derived_cond_pushdown.result b/mysql-test/main/derived_cond_pushdown.result
@@ -15567,7 +15567,6 @@ EXPLAIN
 {
   "query_block": {
     "select_id": 1,
-    "const_condition": "1",
     "table": {
       "table_name": "t1",
       "access_type": "ALL",
@@ -16751,7 +16750,6 @@ EXPLAIN
         "lateral": 1,
         "query_block": {
           "select_id": 3,
-          "const_condition": "1",
           "outer_ref_condition": "t4.c is not null",
           "table": {
             "table_name": "t3",

diff --git a/mysql-test/main/derived_split_innodb.result b/mysql-test/main/derived_split_innodb.result
@@ -367,7 +367,6 @@ ANALYZE
     "select_id": 1,
     "r_loops": 1,
     "r_total_time_ms": "REPLACED",
-    "const_condition": "1",
     "table": {
       "table_name": "t1",
       "access_type": "ALL",

diff --git a/mysql-test/main/explain_json.result b/mysql-test/main/explain_json.result
@@ -602,7 +602,6 @@ EXPLAIN
 {
   "query_block": {
     "select_id": 1,
-    "const_condition": "1",
     "table": {
       "table_name": "t1",
       "access_type": "ALL",
@@ -1252,7 +1251,6 @@ EXPLAIN
 {
   "query_block": {
     "select_id": 1,
-    "const_condition": "1",
     "table": {
       "table_name": "t2",
       "access_type": "const",
@@ -1277,7 +1275,6 @@ ANALYZE
     "select_id": 1,
     "r_loops": 1,
     "r_total_time_ms": "REPLACED",
-    "const_condition": "1",
     "table": {
       "table_name": "t2",
       "access_type": "const",

diff --git a/mysql-test/main/having_cond_pushdown.result b/mysql-test/main/having_cond_pushdown.result
@@ -3202,7 +3202,6 @@ EXPLAIN
 {
   "query_block": {
     "select_id": 1,
-    "const_condition": "1",
     "table": {
       "table_name": "t1",
       "access_type": "ALL",
@@ -3544,7 +3543,6 @@ EXPLAIN
 {
   "query_block": {
     "select_id": 1,
-    "const_condition": "1 and 1",
     "table": {
       "table_name": "t1",
       "access_type": "ALL",
@@ -3671,7 +3669,6 @@ EXPLAIN
 {
   "query_block": {
     "select_id": 1,
-    "const_condition": "1",
     "table": {
       "table_name": "t1",
       "access_type": "ALL",
@@ -3799,7 +3796,6 @@ EXPLAIN
 {
   "query_block": {
     "select_id": 1,
-    "const_condition": "1",
     "filesort": {
       "sort_key": "t1.c",
       "temporary_table": {
@@ -3867,7 +3863,6 @@ EXPLAIN
 {
   "query_block": {
     "select_id": 1,
-    "const_condition": "1 and 1",
     "table": {
       "table_name": "t1",
       "access_type": "ALL",
@@ -3985,7 +3980,6 @@ EXPLAIN
 {
   "query_block": {
     "select_id": 1,
-    "const_condition": "1",
     "table": {
       "table_name": "t3",
       "access_type": "ALL",

diff --git a/mysql-test/main/join_cache_debug.result b/mysql-test/main/join_cache_debug.result
@@ -38,7 +38,6 @@ JSON
     "select_id": 1,
     "r_loops": 1,
     "r_total_time_ms": "REPLACED",
-    "const_condition": "1",
     "table": {
       "table_name": "t1_t2",
       "access_type": "ALL",

diff --git a/mysql-test/main/subselect4.result b/mysql-test/main/subselect4.result
@@ -3332,3 +3332,37 @@ Variable_name	Value
 Handler_read_rnd_next	0
 drop table t1,t2,t3;
 # End of 10.4 tests
+#
+# MDEV-32866: Debug assertion failure in Item_subselect::val_bool()
+#
+CREATE TABLE t1(a INT);
+INSERT INTO t1(a) VALUES (1);
+SELECT a FROM t1 WHERE (SELECT a,a) IN (SELECT a,a);
+a
+1
+SELECT a FROM t1 WHERE (SELECT a,a UNION SELECT 1,a FROM t1) IN (SELECT 1,1);
+a
+1
+SELECT a FROM t1 WHERE (SELECT a,a UNION SELECT 1,a FROM t1) IN (SELECT a,a);
+a
+1
+DROP TABLE t1;
+# Test case from duplicating MDEV-22375
+CREATE TABLE t1 (a INT KEY,b CHAR(1));
+INSERT INTO t1 VALUES (0,'1');
+SELECT a FROM t1 WHERE '' IN (SELECT 'x' LIKE a HAVING a LIKE a);
+a
+0
+Warnings:
+Warning	1292	Truncated incorrect DECIMAL value: ''
+DROP TABLE t1;
+#
+# MDEV-35654: Re-evaluation of constant subquery triggers debug assertion
+#
+CREATE TABLE t1 (a INT);
+INSERT INTO t1 VALUES (
+a IN (SELECT a IN (
+SELECT 1 FROM (SELECT 1 AS a) AS dt WHERE a IN (SELECT a HAVING a=0)
+)));
+DROP TABLE t1;
+# End of 10.5 tests
diff --git a/mysql-test/main/subselect4.test b/mysql-test/main/subselect4.test
@@ -2684,3 +2684,32 @@ show status like 'Handler_read_rnd_next%';
 drop table t1,t2,t3;
 
 --echo # End of 10.4 tests
+
+--echo #
+--echo # MDEV-32866: Debug assertion failure in Item_subselect::val_bool()
+--echo #
+CREATE TABLE t1(a INT);
+INSERT INTO t1(a) VALUES (1);
+
+SELECT a FROM t1 WHERE (SELECT a,a) IN (SELECT a,a);
+SELECT a FROM t1 WHERE (SELECT a,a UNION SELECT 1,a FROM t1) IN (SELECT 1,1);
+SELECT a FROM t1 WHERE (SELECT a,a UNION SELECT 1,a FROM t1) IN (SELECT a,a);
+DROP TABLE t1;
+
+--echo # Test case from duplicating MDEV-22375
+CREATE TABLE t1 (a INT KEY,b CHAR(1));
+INSERT INTO t1 VALUES (0,'1');
+SELECT a FROM t1 WHERE '' IN (SELECT 'x' LIKE a HAVING a LIKE a);
+DROP TABLE t1;
+
+--echo #
+--echo # MDEV-35654: Re-evaluation of constant subquery triggers debug assertion
+--echo #
+CREATE TABLE t1 (a INT);
+INSERT INTO t1 VALUES (
+  a IN (SELECT a IN (
+    SELECT 1 FROM (SELECT 1 AS a) AS dt WHERE a IN (SELECT a HAVING a=0)
+  )));
+DROP TABLE t1;
+
+--echo # End of 10.5 tests
diff --git a/mysql-test/main/subselect_mat_analyze_json.result b/mysql-test/main/subselect_mat_analyze_json.result
@@ -430,7 +430,6 @@ ANALYZE
     "select_id": 1,
     "r_loops": 1,
     "r_total_time_ms": "REPLACED",
-    "const_condition": "1",
     "table": {
       "table_name": "t1",
       "access_type": "ALL",

diff --git a/sql/item.h b/sql/item.h
@@ -2197,6 +2197,8 @@ class Item: public Value_source,
     If there is some, sets a bit for this key in the proper key map.
   */
   virtual bool check_index_dependence(void *arg) { return 0; }
+  /* Mark all applicable items in the tree as constant */
+  virtual bool make_const_processor(void *arg) { return 0; }
   /*============== End of Item processor list ======================*/
 
   /*

diff --git a/sql/item_subselect.cc b/sql/item_subselect.cc
@@ -397,6 +397,13 @@ bool Item_subselect::eliminate_subselect_processor(void *arg)
 }
 
 
+bool Item_subselect::make_const_processor(void *arg)
+{
+  make_const();
+  return FALSE;
+}
+
+
 bool Item_subselect::mark_as_dependent(THD *thd, st_select_lex *select, 
                                        Item *item)
 {

diff --git a/sql/item_subselect.h b/sql/item_subselect.h
@@ -204,8 +204,9 @@ class Item_subselect :public Item_result_field,
   void recalc_used_tables(st_select_lex *new_parent, bool after_pullout);
   virtual bool exec();
   /*
-    If subquery optimization or execution determines that the subquery has
-    an empty result, mark the subquery predicate as a constant value.
+    Called if we've managed to calculate the value of this subquery
+    during optimization or execution, hence it can be considered constant
+    at all subsequent steps.
   */
   void make_const()
   { 
@@ -262,6 +263,7 @@ class Item_subselect :public Item_result_field,
     @retval FALSE otherwise
   */
   bool is_expensive_processor(void *arg) override { return is_expensive(); }
+  bool make_const_processor(void *arg) override;
   bool update_table_bitmaps_processor(void *arg) override;
 
   /**

diff --git a/sql/sql_select.cc b/sql/sql_select.cc
@@ -11819,6 +11819,7 @@ make_join_select(JOIN *join,SQL_SELECT *select,COND *cond)
           {
             trace_const_cond.add("evaluated", "false")
                             .add("cause", "expensive cond");
+            join->exec_const_cond= const_cond;
           }
           else
           {
@@ -11827,16 +11828,19 @@ make_join_select(JOIN *join,SQL_SELECT *select,COND *cond)
               Json_writer_array a(thd, "computing_condition");
               const_cond_result= const_cond->val_int() != 0;
             }
+            /*
+              Once we evaluated const_cond, we can mark all applicable items
+              in the tree as constant to avoid their re-evaluation
+            */
+            const_cond->walk(&Item::make_const_processor, false, nullptr);
             if (!const_cond_result)
             {
               DBUG_PRINT("info",("Found impossible WHERE condition"));
               trace_const_cond.add("evaluated", "true")
                               .add("found", "impossible where");
-              join->exec_const_cond= NULL;
               DBUG_RETURN(1);
             }
           }
-          join->exec_const_cond= const_cond;
         }
 
         if (join->table_count != join->const_tables)

diff --git a/sql/sql_select.h b/sql/sql_select.h
@@ -1503,9 +1503,9 @@ class JOIN :public Sql_alloc
   COND_EQUAL *cond_equal;
   COND_EQUAL *having_equal;
   /*
-    Constant codition computed during optimization, but evaluated during
-    join execution. Typically expensive conditions that should not be
-    evaluated at optimization time.
+    Constant part of conditions which is extracted during optimization, but
+    evaluated during join execution. Typically expensive conditions that
+    should not be evaluated at optimization time.
   */
   Item *exec_const_cond;
   /*