MDEV-5740: Assertion `!derived->first_select()->exclude_from_table_unique_test || derived->outer_select()-> exclude_from_table_unique_test' failed on 2nd execution of PS with derived_merge

Do not check tables of executed units.
Debug info about stages of derived tables execution added.

mysql-test/r/derived_view.result

@@ -2356,6 +2356,46 @@ id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
 3	DEPENDENT SUBQUERY	pi	ref	gallery_id	gallery_id	4	test.gal.id	4	Using temporary; Using filesort
 drop table galleries, pictures;
 #
+# MDEV-5740: Assertion 
+#`!derived->first_select()->exclude_from_table_unique_test ||
+#derived->outer_select()-> exclude_from_table_unique_test'
+#failed on 2nd execution of PS with derived_merge
+#
+set @save_optimizer_switch5740=@@optimizer_switch;
+SET optimizer_switch = 'derived_merge=on';
+CREATE TABLE t1 (a INT);
+INSERT INTO t1 VALUES (1),(2);
+CREATE TABLE t2 (b INT);
+INSERT INTO t2 VALUES (3),(4);
+PREPARE stmt FROM '
+  INSERT INTO t1 SELECT * FROM t2 UNION SELECT * FROM (SELECT * FROM t1) AS sq  
+';
+EXECUTE stmt;
+select * from t1;
+a
+1
+2
+3
+4
+1
+2
+EXECUTE stmt;
+select * from t1;
+a
+1
+2
+3
+4
+1
+2
+3
+4
+1
+2
+deallocate prepare stmt;
+drop table t1,t2;
+set optimizer_switch=@save_optimizer_switch5740;
+#
 # end of 5.3 tests
 #
 set optimizer_switch=@exit_optimizer_switch;

mysql-test/t/derived_view.test

@@ -1703,6 +1703,33 @@ ORDER BY gallery_name ASC
 
 drop table galleries, pictures;
 
+--echo #
+--echo # MDEV-5740: Assertion 
+--echo #`!derived->first_select()->exclude_from_table_unique_test ||
+--echo #derived->outer_select()-> exclude_from_table_unique_test'
+--echo #failed on 2nd execution of PS with derived_merge
+--echo #
+
+set @save_optimizer_switch5740=@@optimizer_switch;
+SET optimizer_switch = 'derived_merge=on';
+
+CREATE TABLE t1 (a INT);
+INSERT INTO t1 VALUES (1),(2);
+CREATE TABLE t2 (b INT);
+INSERT INTO t2 VALUES (3),(4);
+
+PREPARE stmt FROM '
+  INSERT INTO t1 SELECT * FROM t2 UNION SELECT * FROM (SELECT * FROM t1) AS sq  
+';
+EXECUTE stmt;
+select * from t1;
+EXECUTE stmt;
+select * from t1;
+deallocate prepare stmt;
+
+drop table t1,t2;
+set optimizer_switch=@save_optimizer_switch5740;
+
 --echo #
 --echo # end of 5.3 tests
 --echo #

sql/sql_base.cc

@@ -1735,6 +1735,17 @@ retry:
   DBUG_PRINT("info", ("real table: %s.%s", d_name, t_name));
   for (TABLE_LIST *tl= table_list;;)
   {
+    if (tl &&
+        tl->select_lex && tl->select_lex->master_unit() &&
+        tl->select_lex->master_unit()->executed)
+    {
+      /*
+        There is no sense to check tables of already executed parts
+        of the query
+      */
+      tl= tl->next_global;
+      continue;
+    }
     if (((! (res= find_table_in_global_list(tl, d_name, t_name))) &&
          (! (res= mysql_lock_have_duplicate(thd, table, tl)))) ||
         ((!res->table || res->table != table->table) &&

sql/sql_derived.cc

@@ -64,8 +64,10 @@ mysql_handle_derived(LEX *lex, uint phases)
 {
   bool res= FALSE;
   THD *thd= lex->thd;
+  DBUG_ENTER("mysql_handle_derived");
+  DBUG_PRINT("enter", ("phases: 0x%x", phases));
   if (!lex->derived_tables)
-    return FALSE;
+    DBUG_RETURN(FALSE);
 
   lex->thd->derived_tables_processing= TRUE;
 
@@ -123,7 +125,7 @@ mysql_handle_derived(LEX *lex, uint phases)
     }
   }
   lex->thd->derived_tables_processing= FALSE;
-  return res;
+  DBUG_RETURN(res);
 }
 
 /*
@@ -163,8 +165,10 @@ mysql_handle_single_derived(LEX *lex, TABLE_LIST *derived, uint phases)
   THD *thd= lex->thd;
   uint8 allowed_phases= (derived->is_merged_derived() ? DT_PHASES_MERGE :
                          DT_PHASES_MATERIALIZE);
+  DBUG_ENTER("mysql_handle_single_derived");
+  DBUG_PRINT("enter", ("phases: 0x%x  allowed: 0x%x", phases, allowed_phases));
   if (!lex->derived_tables)
-    return FALSE;
+    DBUG_RETURN(FALSE);
 
   lex->thd->derived_tables_processing= TRUE;
 
@@ -186,7 +190,7 @@ mysql_handle_single_derived(LEX *lex, TABLE_LIST *derived, uint phases)
       break;
   }
   lex->thd->derived_tables_processing= FALSE;
-  return res;
+  DBUG_RETURN(res);
 }
 
 
@@ -353,16 +357,17 @@ bool mysql_derived_merge(THD *thd, LEX *lex, TABLE_LIST *derived)
   uint tablenr;
   SELECT_LEX *parent_lex= derived->select_lex;
   Query_arena *arena, backup;
+  DBUG_ENTER("mysql_derived_merge");
 
   if (derived->merged)
-    return FALSE;
+    DBUG_RETURN(FALSE);
 
   if (dt_select->uncacheable & UNCACHEABLE_RAND)
   {
     /* There is random function => fall back to materialization. */
     derived->change_refs_to_fields();
     derived->set_materialized_derived();
-    return FALSE;
+    DBUG_RETURN(FALSE);
   }
 
  if (thd->lex->sql_command == SQLCOM_UPDATE_MULTI ||
@@ -466,7 +471,7 @@ bool mysql_derived_merge(THD *thd, LEX *lex, TABLE_LIST *derived)
 exit_merge:
   if (arena)
     thd->restore_active_arena(arena, &backup);
-  return res;
+  DBUG_RETURN(res);
 }
 
 
@@ -492,14 +497,15 @@ exit_merge:
 
 bool mysql_derived_merge_for_insert(THD *thd, LEX *lex, TABLE_LIST *derived)
 {
+  DBUG_ENTER("mysql_derived_merge_for_insert");
   if (derived->merged_for_insert)
-    return FALSE;
+    DBUG_RETURN(FALSE);
   if (derived->is_materialized_derived())
-    return mysql_derived_prepare(thd, lex, derived);
+    DBUG_RETURN(mysql_derived_prepare(thd, lex, derived));
   if (!derived->is_multitable())
   {
     if (!derived->single_table_updatable())
-      return derived->create_field_translation(thd);
+      DBUG_RETURN(derived->create_field_translation(thd));
     if (derived->merge_underlying_list)
     {
       derived->table= derived->merge_underlying_list->table;
@@ -507,7 +513,7 @@ bool mysql_derived_merge_for_insert(THD *thd, LEX *lex, TABLE_LIST *derived)
       derived->merged_for_insert= TRUE;
     }
   }  
-  return FALSE;
+  DBUG_RETURN(FALSE);
 }
 
 
@@ -764,9 +770,10 @@ bool mysql_derived_optimize(THD *thd, LEX *lex, TABLE_LIST *derived)
   SELECT_LEX *save_current_select= lex->current_select;
 
   bool res= FALSE;
+  DBUG_ENTER("mysql_derived_optimize");
 
   if (unit->optimized)
-    return FALSE;
+    DBUG_RETURN(FALSE);
   lex->current_select= first_select;
 
   if (unit->is_union())
@@ -806,7 +813,7 @@ bool mysql_derived_optimize(THD *thd, LEX *lex, TABLE_LIST *derived)
   }
 err:
   lex->current_select= save_current_select;
-  return res;
+  DBUG_RETURN(res);
 }
 
 
@@ -829,11 +836,12 @@ err:
 
 bool mysql_derived_create(THD *thd, LEX *lex, TABLE_LIST *derived)
 {
+  DBUG_ENTER("mysql_derived_create");
   TABLE *table= derived->table;
   SELECT_LEX_UNIT *unit= derived->get_unit();
 
   if (table->created)
-    return FALSE;
+    DBUG_RETURN(FALSE);
   select_union *result= (select_union*)unit->result;
   if (table->s->db_type() == TMP_ENGINE_HTON)
   {
@@ -843,13 +851,13 @@ bool mysql_derived_create(THD *thd, LEX *lex, TABLE_LIST *derived)
                                   &result->tmp_table_param.recinfo,
                                   (unit->first_select()->options |
                                    thd->options | TMP_TABLE_ALL_COLUMNS)))
-      return(TRUE);
+      DBUG_RETURN(TRUE);
   }
   if (open_tmp_table(table))
-    return TRUE;
+    DBUG_RETURN(TRUE);
   table->file->extra(HA_EXTRA_WRITE_CACHE);
   table->file->extra(HA_EXTRA_IGNORE_DUP_KEY);
-  return FALSE;
+  DBUG_RETURN(FALSE);
 }
 
 
@@ -879,11 +887,12 @@ bool mysql_derived_create(THD *thd, LEX *lex, TABLE_LIST *derived)
 
 bool mysql_derived_fill(THD *thd, LEX *lex, TABLE_LIST *derived)
 {
+  DBUG_ENTER("mysql_derived_fill");
   SELECT_LEX_UNIT *unit= derived->get_unit();
   bool res= FALSE;
 
   if (unit->executed && !unit->uncacheable && !unit->describe)
-    return FALSE;
+    DBUG_RETURN(FALSE);
   /*check that table creation passed without problems. */
   DBUG_ASSERT(derived->table && derived->table->created);
   SELECT_LEX *first_select= unit->first_select();
@@ -925,7 +934,7 @@ bool mysql_derived_fill(THD *thd, LEX *lex, TABLE_LIST *derived)
     unit->cleanup();
   lex->current_select= save_current_select;
 
-  return res;
+  DBUG_RETURN(res);
 }
 
 
@@ -949,6 +958,7 @@ bool mysql_derived_fill(THD *thd, LEX *lex, TABLE_LIST *derived)
 
 bool mysql_derived_reinit(THD *thd, LEX *lex, TABLE_LIST *derived)
 {
+  DBUG_ENTER("mysql_derived_reinit");
   st_select_lex_unit *unit= derived->get_unit();
 
   if (derived->table)
@@ -958,5 +968,5 @@ bool mysql_derived_reinit(THD *thd, LEX *lex, TABLE_LIST *derived)
   /* for derived tables & PS (which can't be reset by Item_subquery) */
   unit->reinit_exec_mechanism();
   unit->set_thd(thd);
-  return FALSE;
+  DBUG_RETURN(FALSE);
 }

sql/table.h

@@ -1791,9 +1791,11 @@ struct TABLE_LIST
   }
   inline void set_merged_derived()
   {
+    DBUG_ENTER("set_merged_derived");
     derived_type= ((derived_type & DTYPE_MASK) |
                    DTYPE_TABLE | DTYPE_MERGE);
     set_check_merged();
+    DBUG_VOID_RETURN;
   }
   inline bool is_materialized_derived()
   {
@@ -1801,9 +1803,11 @@ struct TABLE_LIST
   }
   void set_materialized_derived()
   {
+    DBUG_ENTER("set_materialized_derived");
     derived_type= ((derived_type & DTYPE_MASK) |
                    DTYPE_TABLE | DTYPE_MATERIALIZE);
     set_check_materialized();
+    DBUG_VOID_RETURN;
   }
   inline bool is_multitable()
   {