Fixed LP bug #794901.

Also:
1. simplified the code of the function mysql_derived_merge_for_insert.
2. moved merge of views/dt for multi-update/delete to the prepare stage.
3. the list of the references to the candidates for semi-join now is
   allocated in the statement memory.

mysql-test/r/derived_view.result

@@ -1003,3 +1003,16 @@ Warnings:
 Note	1003	select `test`.`t2`.`a` AS `a`,0 AS `a`,0 AS `b` from `test`.`t1` left join `test`.`t2` on((0 <> 0)) where <expr_cache><0>(<in_optimizer>(0,<exists>(select 0 from `test`.`t1` where (<cache>(0) = 0))))
 DROP VIEW v1;
 DROP TABLE t1,t2;
+#
+# LP bug #794901: insert into a multi-table view           
+#
+CREATE TABLE t1 (a int);
+CREATE TABLE t2 (a int);
+CREATE TABLE t3 (a int);
+CREATE VIEW v1 AS SELECT t1.a FROM t1,t2;
+CREATE VIEW v2 AS SELECT a FROM t2 GROUP BY a;
+CREATE VIEW v3 AS SELECT v1.a FROM v1,v2;
+INSERT INTO v3(a) VALUES (1);
+ERROR HY000: The target table v3 of the INSERT is not insertable-into
+DROP VIEW v1,v2,v3;
+DROP TABLE t1,t2,t3;

mysql-test/t/derived_view.test

@@ -582,3 +582,21 @@ SELECT * FROM t2 RIGHT JOIN v1 AS t ON t.a != 0
 
 DROP VIEW v1;
 DROP TABLE t1,t2;
+
+--echo #
+--echo # LP bug #794901: insert into a multi-table view           
+--echo #
+
+CREATE TABLE t1 (a int);
+CREATE TABLE t2 (a int);
+CREATE TABLE t3 (a int);
+
+CREATE VIEW v1 AS SELECT t1.a FROM t1,t2;
+CREATE VIEW v2 AS SELECT a FROM t2 GROUP BY a;
+CREATE VIEW v3 AS SELECT v1.a FROM v1,v2;
+
+-- error ER_NON_INSERTABLE_TABLE
+INSERT INTO v3(a) VALUES (1);
+
+DROP VIEW v1,v2,v3;
+DROP TABLE t1,t2,t3;

sql/item_subselect.cc

@@ -1147,6 +1147,7 @@ Item_in_subselect::Item_in_subselect(Item * left_exp,
   Item_exists_subselect(), left_expr_cache(0), first_execution(TRUE),
   optimizer(0), pushed_cond_guards(NULL), in_strategy(0),
   is_jtbm_merged(FALSE), is_flattenable_semijoin(FALSE),
+  is_registered_semijoin(FALSE), 
   upper_item(0)
 {
   DBUG_ENTER("Item_in_subselect::Item_in_subselect");

sql/item_subselect.h

@@ -458,6 +458,11 @@ class Item_in_subselect :public Item_exists_subselect
   */
   bool is_flattenable_semijoin;
 
+  /*
+    TRUE<=>registered in the list of semijoins in outer select
+  */
+  bool is_registered_semijoin;
+
   /*
     Used to determine how this subselect item is represented in the item tree,
     in case there is a need to locate it there and replace with something else.

sql/sql_delete.cc

@@ -603,9 +603,11 @@ int mysql_multi_delete_prepare(THD *thd)
                                     &thd->lex->select_lex.top_join_list,
                                     lex->query_tables,
                                     lex->select_lex.leaf_tables, FALSE, 
-                                    DELETE_ACL, SELECT_ACL, TRUE))
+                                    DELETE_ACL, SELECT_ACL, FALSE))
     DBUG_RETURN(TRUE);
 
+  if (lex->select_lex.handle_derived(thd->lex, DT_MERGE))  
+    DBUG_RETURN(TRUE);
 
   /*
     Multi-delete can't be constructed over-union => we always have

sql/sql_derived.cc

@@ -346,10 +346,17 @@ bool mysql_derived_merge(THD *thd, LEX *lex, TABLE_LIST *derived)
   if (derived->merged)
     return FALSE;
 
+ if (thd->lex->sql_command == SQLCOM_UPDATE_MULTI ||
+     thd->lex->sql_command == SQLCOM_DELETE_MULTI)
+   thd->save_prep_leaf_list= TRUE;
+
   arena= thd->activate_stmt_arena_if_needed(&backup);  // For easier test
   derived->merged= TRUE;
 
-  if (!derived->merged_for_insert)
+  if (!derived->merged_for_insert || 
+      (derived->is_multitable() && 
+       (thd->lex->sql_command == SQLCOM_UPDATE_MULTI ||
+        thd->lex->sql_command == SQLCOM_DELETE_MULTI)))
   {
     /*
       Check whether there is enough free bits in table map to merge subquery.
@@ -392,7 +399,7 @@ bool mysql_derived_merge(THD *thd, LEX *lex, TABLE_LIST *derived)
     }
 
     /* Merge derived table's subquery in the parent select. */
-    if (parent_lex->merge_subquery(derived, dt_select, tablenr, map))
+    if (parent_lex->merge_subquery(thd, derived, dt_select, tablenr, map))
     {
       res= TRUE;
       goto exit_merge;
@@ -468,8 +475,6 @@ bool mysql_derived_merge(THD *thd, LEX *lex, TABLE_LIST *derived)
 
 bool mysql_derived_merge_for_insert(THD *thd, LEX *lex, TABLE_LIST *derived)
 {
-  SELECT_LEX *dt_select= derived->get_single_select();
-
   if (derived->merged_for_insert)
     return FALSE;
   if (derived->is_materialized_derived())
@@ -482,43 +487,13 @@ bool mysql_derived_merge_for_insert(THD *thd, LEX *lex, TABLE_LIST *derived)
   {
     if (!derived->updatable)
       return derived->create_field_translation(thd);
-    TABLE_LIST *tl=((TABLE_LIST*)dt_select->table_list.first);
-    TABLE *table= tl->table;
-    /* preserve old map & tablenr. */
-    if (!derived->merged_for_insert && derived->table)
-      table->set_table_map(derived->table->map, derived->table->tablenr);
-
-    derived->table= table;
-    derived->schema_table=
-      ((TABLE_LIST*)dt_select->table_list.first)->schema_table;
-    if (!derived->merged)
+    if (derived->merge_underlying_list)
     {
-      Query_arena *arena, backup;
-      arena= thd->activate_stmt_arena_if_needed(&backup);  // For easier test
-      derived->select_lex->leaf_tables.push_back(tl);
-      derived->nested_join= (NESTED_JOIN*) thd->calloc(sizeof(NESTED_JOIN));
-      if (derived->nested_join)
-      {
-        derived->wrap_into_nested_join(tl->select_lex->top_join_list);
-        derived->get_unit()->exclude_level(); 
-      }
-      if (arena)
-        thd->restore_active_arena(arena, &backup);
-      derived->merged= TRUE;
-      if (!derived->nested_join)
-        return TRUE;
-    }      
+      derived->table= derived->merge_underlying_list->table;
+      derived->schema_table= derived->merge_underlying_list->schema_table;
+      derived->merged_for_insert= TRUE;
     }
-  else
-  {
-    if (thd->lex->sql_command == SQLCOM_UPDATE_MULTI ||
-        thd->lex->sql_command == SQLCOM_DELETE_MULTI)
-      thd->save_prep_leaf_list= TRUE;
-    if (!derived->merged_for_insert && mysql_derived_merge(thd, lex, derived))
-      return TRUE;
   }  
-  derived->merged_for_insert= TRUE;
-
   return FALSE;
 }
 

sql/sql_insert.cc

@@ -135,7 +135,7 @@ bool check_view_single_update(List<Item> &fields, List<Item> *values,
     A buffer for the insert values was allocated for the merged view.
     Use it.
   */
-  //tbl->table->insert_values= view->table->insert_values;
+  tbl->table->insert_values= view->table->insert_values;
   view->table= tbl->table;
   *map= tables;
 

sql/sql_lex.cc

@@ -1647,6 +1647,7 @@ void st_select_lex::init_select()
 {
   st_select_lex_node::init_select();
   sj_nests.empty();
+  sj_subselects.empty();
   group_list.empty();
   type= db= 0;
   having= 0;
@@ -3235,12 +3236,6 @@ bool st_select_lex::get_free_table_map(table_map *map, uint *tablenr)
   *map= 0;
   *tablenr= 0;
   TABLE_LIST *tl;
-  if (!join)
-  {
-    (*map)= 1<<1;
-    (*tablenr)++;
-    return FALSE;
-  }
   List_iterator<TABLE_LIST> ti(leaf_tables);
   while ((tl= ti++))
   {
@@ -3397,7 +3392,8 @@ void st_select_lex::remap_tables(TABLE_LIST *derived, table_map map,
   @return FALSE ok
 */
 
-bool SELECT_LEX::merge_subquery(TABLE_LIST *derived, SELECT_LEX *subq_select,
+bool SELECT_LEX::merge_subquery(THD *thd, TABLE_LIST *derived,
+                                SELECT_LEX *subq_select,
                                 uint table_no, table_map map)
 {
   derived->wrap_into_nested_join(subq_select->top_join_list);
@@ -3405,19 +3401,17 @@ bool SELECT_LEX::merge_subquery(TABLE_LIST *derived, SELECT_LEX *subq_select,
   leaf_tables.concat(&subq_select->leaf_tables);
 
   ftfunc_list->concat(subq_select->ftfunc_list);
-  if (join)
-  {
-    Item_in_subselect **in_subq;
-    Item_in_subselect **in_subq_end;
-    for (in_subq= subq_select->join->sj_subselects.front(), 
-         in_subq_end= subq_select->join->sj_subselects.back(); 
-         in_subq != in_subq_end; 
-         in_subq++)
-    {
-      join->sj_subselects.append(join->thd->mem_root, *in_subq);
-      DBUG_ASSERT((*in_subq)->emb_on_expr_nest != NULL);
-      if ((*in_subq)->emb_on_expr_nest == NO_JOIN_NEST)
-        (*in_subq)->emb_on_expr_nest= derived;
+  if (join ||
+      thd->lex->sql_command == SQLCOM_UPDATE_MULTI ||
+      thd->lex->sql_command == SQLCOM_DELETE_MULTI)
+  {
+    List_iterator_fast<Item_in_subselect> li(subq_select->sj_subselects);
+    Item_in_subselect *in_subq;
+    while ((in_subq= li++))
+    {
+      sj_subselects.push_back(in_subq);
+      if (in_subq->emb_on_expr_nest == NO_JOIN_NEST)
+         in_subq->emb_on_expr_nest= derived;
     }
   }
   /*

sql/sql_lex.h

@@ -637,6 +637,12 @@ class st_select_lex: public st_select_lex_node
     tables. Unlike 'next_local', this in this list views are *not*
     leaves. Created in setup_tables() -> make_leaves_list().
   */
+  /* 
+    Subqueries that will need to be converted to semi-join nests, including
+    those converted to jtbm nests. The list is emptied when conversion is done.
+  */
+  List<Item_in_subselect> sj_subselects;
+
   List<TABLE_LIST> leaf_tables;
   List<TABLE_LIST> leaf_tables_exec;
   List<TABLE_LIST> leaf_tables_prep;
@@ -886,7 +892,7 @@ class st_select_lex: public st_select_lex_node
   void remove_table_from_list(TABLE_LIST *table);
   void remap_tables(TABLE_LIST *derived, table_map map,
                     uint tablenr, st_select_lex *parent_lex);
-  bool merge_subquery(TABLE_LIST *derived, st_select_lex *subq_lex,
+  bool merge_subquery(THD *thd, TABLE_LIST *derived, st_select_lex *subq_lex,
                       uint tablenr, table_map map);
   inline bool is_mergeable()
   {

sql/sql_select.cc

@@ -13033,7 +13033,7 @@ void setup_tmp_table_column_bitmaps(TABLE *table, uchar *bitmaps)
 */
 
 TABLE *
-create_tmp_table(THD *thd,TMP_TABLE_PARAM *param,List<Item> &fields,
+create_tmp_table(THD *thd, TMP_TABLE_PARAM *param, List<Item> &fields,
 		 ORDER *group, bool distinct, bool save_sum_fields,
 		 ulonglong select_options, ha_rows rows_limit,
                  char *table_alias, bool do_not_open)

sql/sql_select.h

@@ -964,11 +964,6 @@ class JOIN :public Sql_alloc
   bool optimized; ///< flag to avoid double optimization in EXPLAIN
   bool initialized; ///< flag to avoid double init_execution calls
 
-  /* 
-    Subqueries that will need to be converted to semi-join nests, including
-    those converted to jtbm nests. The list is emptied when conversion is done.
-  */
-  Array<Item_in_subselect> sj_subselects;
   /*
     Additional WHERE and HAVING predicates to be considered for IN=>EXISTS
     subquery transformation of a JOIN object.
@@ -998,7 +993,7 @@ class JOIN :public Sql_alloc
 
   JOIN(THD *thd_arg, List<Item> &fields_arg, ulonglong select_options_arg,
        select_result *result_arg)
-    :fields_list(fields_arg), sj_subselects(thd_arg->mem_root, 4)
+    :fields_list(fields_arg)
   {
     init(thd_arg, fields_arg, select_options_arg, result_arg);
   }

sql/sql_update.cc

@@ -248,6 +248,7 @@ int mysql_update(THD *thd,
       DBUG_RETURN(1);
     close_tables_for_reopen(thd, &table_list);
   }
+
   if (table_list->handle_derived(thd->lex, DT_MERGE_FOR_INSERT))
     DBUG_RETURN(1);
   if (table_list->handle_derived(thd->lex, DT_PREPARE))
@@ -1037,10 +1038,10 @@ int mysql_multi_update_prepare(THD *thd)
     second time, but this call will do nothing (there are check for second
     call in setup_tables()).
   */
+
   //We need to merge for insert prior to prepare.
   if (mysql_handle_derived(lex, DT_MERGE_FOR_INSERT))
     DBUG_RETURN(TRUE);
-
   if (mysql_handle_derived(lex, DT_PREPARE))
     DBUG_RETURN(TRUE);
 
@@ -1048,7 +1049,10 @@ int mysql_multi_update_prepare(THD *thd)
                                     &lex->select_lex.top_join_list,
                                     table_list,
                                     lex->select_lex.leaf_tables, FALSE,
-                                    UPDATE_ACL, SELECT_ACL, TRUE))
+                                    UPDATE_ACL, SELECT_ACL, FALSE))
+    DBUG_RETURN(TRUE);
+
+  if (lex->select_lex.handle_derived(thd->lex, DT_MERGE))  
     DBUG_RETURN(TRUE);
 
   if (setup_fields_with_no_wrap(thd, 0, *fields, MARK_COLUMNS_WRITE, 0, 0))
@@ -1334,13 +1338,6 @@ int multi_update::prepare(List<Item> &not_used_values,
   thd->cuted_fields=0L;
   thd_proc_info(thd, "updating main table");
 
-  SELECT_LEX *select_lex= lex_unit->first_select();
-  if (select_lex->first_cond_optimization)
-  {
-    if (select_lex->handle_derived(thd->lex, DT_MERGE))
-      DBUG_RETURN(TRUE);
-  }
-
   tables_to_update= get_table_map(fields);
 
   if (!tables_to_update)