Fixed bug mdev-11072.

In a general case the conditions with outer fields cannot
be pushed into materialized views / derived tables.
However if the outer field in the condition refers to a
single row table then the condition may be pushable.
In this case a special care should be taken for outer
fields when pushing the condition into a materialized view /
derived table.

mysql-test/r/derived_cond_pushdown.result

@@ -7083,3 +7083,87 @@ a
 3
 6
 drop table t1;
+#
+# MDEV-11072: pushdown of the condition obtained
+#             after constant row substitution
+#
+CREATE TABLE t1 (a INT);
+CREATE TABLE t2 (b INT);
+CREATE OR REPLACE VIEW v2 AS SELECT * FROM t2;
+CREATE TABLE t3 (c INT);
+CREATE OR REPLACE ALGORITHM=TEMPTABLE VIEW v3 AS SELECT * FROM t3;
+SELECT * FROM t1 WHERE a IN ( 
+SELECT b FROM v2 WHERE b < a OR b IN ( 
+SELECT c FROM v3 WHERE c = a 
+) 
+);
+a
+INSERT INTO t1 VALUES (2);
+INSERT INTO t2 VALUES (3), (2);
+INSERT INTO t3 VALUES (4), (1), (2), (7);
+SELECT * FROM t1 WHERE a IN ( 
+SELECT b FROM v2 WHERE b < a OR b IN ( 
+SELECT c FROM v3 WHERE c = a 
+) 
+);
+a
+2
+EXPLAIN FORMAT=JSON
+SELECT * FROM t1 WHERE a IN ( 
+SELECT b FROM v2 WHERE b < a OR b IN ( 
+SELECT c FROM v3 WHERE c = a 
+) 
+);
+EXPLAIN
+{
+  "query_block": {
+    "select_id": 1,
+    "const_condition": "(0 or <in_optimizer>(2,<exists>(subquery#3)))",
+    "table": {
+      "table_name": "t1",
+      "access_type": "system",
+      "rows": 1,
+      "filtered": 100
+    },
+    "table": {
+      "table_name": "t2",
+      "access_type": "ALL",
+      "rows": 2,
+      "filtered": 100,
+      "attached_condition": "(t2.b = 2)",
+      "first_match": "t1"
+    },
+    "subqueries": [
+      {
+        "query_block": {
+          "select_id": 3,
+          "table": {
+            "table_name": "<derived5>",
+            "access_type": "index_subquery",
+            "possible_keys": ["key0"],
+            "key": "key0",
+            "key_length": "5",
+            "used_key_parts": ["c"],
+            "ref": ["func"],
+            "rows": 2,
+            "filtered": 100,
+            "materialized": {
+              "query_block": {
+                "select_id": 5,
+                "table": {
+                  "table_name": "t3",
+                  "access_type": "ALL",
+                  "rows": 4,
+                  "filtered": 100,
+                  "attached_condition": "(t3.c = 2)"
+                }
+              }
+            }
+          }
+        }
+      }
+    ]
+  }
+}
+DROP VIEW v2,v3;
+DROP TABLE t1,t2,t3;

mysql-test/t/derived_cond_pushdown.test

@@ -951,3 +951,40 @@ select * from
  order by a limit 5) t where t.a not in (2,9);
 
 drop table t1;
+
+--echo #
+--echo # MDEV-11072: pushdown of the condition obtained
+--echo #             after constant row substitution
+--echo #
+
+CREATE TABLE t1 (a INT);
+CREATE TABLE t2 (b INT);
+CREATE OR REPLACE VIEW v2 AS SELECT * FROM t2;
+CREATE TABLE t3 (c INT);
+CREATE OR REPLACE ALGORITHM=TEMPTABLE VIEW v3 AS SELECT * FROM t3;
+
+SELECT * FROM t1 WHERE a IN ( 
+  SELECT b FROM v2 WHERE b < a OR b IN ( 
+    SELECT c FROM v3 WHERE c = a 
+  ) 
+);
+
+INSERT INTO t1 VALUES (2);
+INSERT INTO t2 VALUES (3), (2);
+INSERT INTO t3 VALUES (4), (1), (2), (7);
+
+SELECT * FROM t1 WHERE a IN ( 
+  SELECT b FROM v2 WHERE b < a OR b IN ( 
+    SELECT c FROM v3 WHERE c = a 
+  ) 
+);
+
+EXPLAIN FORMAT=JSON
+SELECT * FROM t1 WHERE a IN ( 
+  SELECT b FROM v2 WHERE b < a OR b IN ( 
+    SELECT c FROM v3 WHERE c = a 
+  ) 
+);
+
+DROP VIEW v2,v3;
+DROP TABLE t1,t2,t3;

sql/item.h

@@ -1559,7 +1559,9 @@ public:
   virtual bool exclusive_dependence_on_table_processor(void *map)
   { return 0; }
   virtual bool exclusive_dependence_on_grouping_fields_processor(void *arg)
- { return 0; }
+  { return 0; }
+  virtual bool cleanup_excluding_outer_fields_processor(void *arg)
+  { return cleanup_processor(arg); }
 
   virtual Item *get_copy(THD *thd, MEM_ROOT *mem_root)=0;
 
@@ -2662,6 +2664,9 @@ public:
   virtual void print(String *str, enum_query_type query_type);
   bool exclusive_dependence_on_table_processor(void *map);
   bool exclusive_dependence_on_grouping_fields_processor(void *arg);
+  bool cleanup_excluding_outer_fields_processor(void *arg)
+  { return depended_from ? 0 :cleanup_processor(arg); }
+   
   Item *get_copy(THD *thd, MEM_ROOT *mem_root)
   { return get_item_copy<Item_field>(thd, mem_root, this); }
   bool is_outer_field() const

sql/sql_derived.cc

@@ -1195,7 +1195,8 @@ bool pushdown_cond_for_derived(THD *thd, Item *cond, TABLE_LIST *derived)
                                  (uchar*) sl);
       if (extracted_cond_copy)
       {
-       extracted_cond_copy->walk(&Item::cleanup_processor, 0, 0);
+       extracted_cond_copy->walk(
+         &Item::cleanup_excluding_outer_fields_processor, 0, 0);
        sl->cond_pushed_into_where= extracted_cond_copy;
       }      
   
@@ -1230,7 +1231,8 @@ bool pushdown_cond_for_derived(THD *thd, Item *cond, TABLE_LIST *derived)
       */
       extracted_cond_copy= remove_pushed_top_conjuncts(thd, extracted_cond_copy);
   
-      cond_over_grouping_fields->walk(&Item::cleanup_processor, 0, 0);
+      cond_over_grouping_fields->walk(
+        &Item::cleanup_excluding_outer_fields_processor, 0, 0);
       sl->cond_pushed_into_where= cond_over_grouping_fields;
 
       if (!extracted_cond_copy)