Fixed LP bug #794890.

Changed the code that processing of multi-updates and multi-deletes
with multitable views at the prepare stage.

A proper solution would be: never to perform any transformations of views
before and at the prepare stage. Yet it would  require re-engineering
of the code that checks privileges and updatability of views.
Ultimately this re-engineering has to be done to provide a clean solution
for INSERT/UPDATE/DELETE statements that use views.

Fixed a valgrind problem in the function TABLE::use_index.
  

mysql-test/r/derived_view.result

@@ -589,3 +589,28 @@ f1	f1
 224	224
 DROP VIEW v1;
 DROP TABLE t1,t2;
+#
+#  LP bug #794890: abort failure on multi-update with view
+#
+CREATE TABLE t1 (a int);
+INSERT INTO t1 VALUES (20), (7);
+CREATE TABLE t2 (a int);
+INSERT INTO t2 VALUES (7), (9), (7);
+CREATE ALGORITHM=TEMPTABLE VIEW v1 AS SELECT a FROM t1;
+CREATE VIEW v2 AS SELECT t2.a FROM t2, v1 WHERE t2.a=t2.a;
+UPDATE v2 SET a = 2;
+SELECT * FROM t2;
+a
+2
+2
+2
+UPDATE t1,v2 SET t1.a = 3;
+SELECT * FROM t1;
+a
+3
+3
+DELETE t1 FROM t1,v2;
+SELECT * FROM t1;
+a
+DROP VIEW v1,v2;
+DROP TABLE t1,t2;

mysql-test/t/derived_view.test

@@ -235,3 +235,27 @@ SELECT * FROM v1 JOIN t2 ON v1.f1 = t2.f1;
 
 DROP VIEW v1;
 DROP TABLE t1,t2;
+
+--echo #
+--echo #  LP bug #794890: abort failure on multi-update with view
+--echo #
+
+CREATE TABLE t1 (a int);
+INSERT INTO t1 VALUES (20), (7);
+CREATE TABLE t2 (a int);
+INSERT INTO t2 VALUES (7), (9), (7);
+
+CREATE ALGORITHM=TEMPTABLE VIEW v1 AS SELECT a FROM t1;
+
+CREATE VIEW v2 AS SELECT t2.a FROM t2, v1 WHERE t2.a=t2.a;
+UPDATE v2 SET a = 2;
+SELECT * FROM t2;
+
+UPDATE t1,v2 SET t1.a = 3;
+SELECT * FROM t1;
+
+DELETE t1 FROM t1,v2;
+SELECT * FROM t1; 
+
+DROP VIEW v1,v2;
+DROP TABLE t1,t2;

sql/sql_base.cc

@@ -7789,9 +7789,18 @@ bool setup_tables(THD *thd, Name_resolution_context *context,
   if (select_lex->first_cond_optimization)
   {
     leaves.empty();
-    select_lex->leaf_tables_exec.empty();
-    make_leaves_list(leaves, tables, full_table_list, first_select_table);
- 
+    if (!select_lex->is_prep_leaf_list_saved)
+    {
+      make_leaves_list(leaves, tables, full_table_list, first_select_table);
+      select_lex->leaf_tables_exec.empty();
+    }
+    else
+    {
+      List_iterator_fast <TABLE_LIST> ti(select_lex->leaf_tables_prep);
+      while ((table_list= ti++))
+        leaves.push_back(table_list);
+    }
+      
     while ((table_list= ti++))
     {
       TABLE *table= table_list->table;

sql/sql_class.cc

@@ -814,6 +814,7 @@ THD::THD()
   memset(&invoker_user, 0, sizeof(invoker_user));
   memset(&invoker_host, 0, sizeof(invoker_host));
   prepare_derived_at_open= FALSE;
+  save_prep_leaf_list= FALSE;
 }
 
 

sql/sql_class.h

@@ -1571,6 +1571,8 @@ class THD :public Statement,
 
   bool prepare_derived_at_open;
 
+  bool save_prep_leaf_list;
+
 #ifndef MYSQL_CLIENT
   int binlog_setup_trx_data();
 

sql/sql_delete.cc

@@ -61,8 +61,9 @@ bool mysql_delete(THD *thd, TABLE_LIST *table_list, COND *conds,
   if (open_and_lock_tables(thd, table_list))
     DBUG_RETURN(TRUE);
 
-  if (mysql_handle_list_of_derived(thd->lex, table_list, DT_MERGE_FOR_INSERT) ||
-      mysql_handle_list_of_derived(thd->lex, table_list, DT_PREPARE))
+  if (mysql_handle_list_of_derived(thd->lex, table_list, DT_MERGE_FOR_INSERT))
+    DBUG_RETURN(TRUE);
+  if (mysql_handle_list_of_derived(thd->lex, table_list, DT_PREPARE))
     DBUG_RETURN(TRUE);
 
   if (!table_list->updatable)
@@ -550,7 +551,7 @@ int mysql_prepare_delete(THD *thd, TABLE_LIST *table_list, Item **conds)
     fix_inner_refs(thd, all_fields, select_lex, select_lex->ref_pointer_array))
     DBUG_RETURN(TRUE);
 
-  select_lex->fix_prepare_information(thd, conds, &fake_conds);
+  select_lex->fix_prepare_information(thd, conds, &fake_conds); 
   DBUG_RETURN(FALSE);
 }
 
@@ -586,10 +587,11 @@ int mysql_multi_delete_prepare(THD *thd)
   TABLE_LIST *target_tbl;
   DBUG_ENTER("mysql_multi_delete_prepare");
 
-  TABLE_LIST *tables= lex->query_tables;
-  if (mysql_handle_derived(lex, DT_INIT) ||
-      mysql_handle_list_of_derived(lex, tables, DT_MERGE_FOR_INSERT) ||
-      mysql_handle_list_of_derived(lex, tables, DT_PREPARE))
+  if (mysql_handle_derived(lex, DT_INIT))
+    DBUG_RETURN(TRUE);
+  if (mysql_handle_derived(lex, DT_MERGE_FOR_INSERT))
+    DBUG_RETURN(TRUE);
+  if (mysql_handle_derived(lex, DT_PREPARE))
     DBUG_RETURN(TRUE);
   /*
     setup_tables() need for VIEWs. JOIN::prepare() will not do it second
@@ -616,7 +618,8 @@ int mysql_multi_delete_prepare(THD *thd)
        target_tbl= target_tbl->next_local)
   {
 
-    if (!(target_tbl->table= target_tbl->correspondent_table->table))
+    target_tbl->table= target_tbl->correspondent_table->table;
+    if (target_tbl->correspondent_table->is_multitable())
     {
        my_error(ER_VIEW_DELETE_MERGE_VIEW, MYF(0),
                 target_tbl->correspondent_table->view_db.str,
@@ -651,6 +654,10 @@ int mysql_multi_delete_prepare(THD *thd)
     with further calls to unique_table
   */
   lex->select_lex.exclude_from_table_unique_test= FALSE;
+  
+  if (lex->select_lex.save_prep_leaf_tables(thd))
+    DBUG_RETURN(TRUE);
+  
   DBUG_RETURN(FALSE);
 }
 

sql/sql_derived.cc

@@ -85,15 +85,18 @@ mysql_handle_derived(LEX *lex, uint phases)
 	   cursor && !res;
 	   cursor= cursor->next_local)
       {
+        if (!cursor->is_view_or_derived() && phases == DT_MERGE_FOR_INSERT)
+          continue;
         uint8 allowed_phases= (cursor->is_merged_derived() ? DT_PHASES_MERGE :
-                               DT_PHASES_MATERIALIZE);
+                               DT_PHASES_MATERIALIZE | DT_MERGE_FOR_INSERT);
         /*
           Skip derived tables to which the phase isn't applicable.
           TODO: mark derived at the parse time, later set it's type
           (merged or materialized)
         */
         if ((phase_flag != DT_PREPARE && !(allowed_phases & phase_flag)) ||
-            (cursor->merged_for_insert && phase_flag != DT_REINIT))
+            (cursor->merged_for_insert && phase_flag != DT_REINIT &&
+             phase_flag != DT_PREPARE))
           continue;
 	res= (*processors[phase])(lex->thd, lex, cursor);
       }
@@ -345,41 +348,43 @@ bool mysql_derived_merge(THD *thd, LEX *lex, TABLE_LIST *derived)
 
   arena= thd->activate_stmt_arena_if_needed(&backup);  // For easier test
   derived->merged= TRUE;
-  /*
-    Check whether there is enough free bits in table map to merge subquery.
-    If not - materialize it. This check isn't cached so when there is a big
-    and small subqueries, and the bigger one can't be merged it wouldn't
-    block the smaller one.
-  */
-  if (parent_lex->get_free_table_map(&map, &tablenr))
-  {
-    /* There is no enough table bits, fall back to materialization. */
-    derived->change_refs_to_fields();
-    derived->set_materialized_derived();
-    goto exit_merge;
-  }
 
-  if (dt_select->leaf_tables.elements + tablenr > MAX_TABLES)
+  if (!derived->merged_for_insert)
   {
-    /* There is no enough table bits, fall back to materialization. */
-    derived->change_refs_to_fields();
-    derived->set_materialized_derived();
-    goto exit_merge;
-  }
+    /*
+      Check whether there is enough free bits in table map to merge subquery.
+      If not - materialize it. This check isn't cached so when there is a big
+      and small subqueries, and the bigger one can't be merged it wouldn't
+      block the smaller one.
+    */
+    if (parent_lex->get_free_table_map(&map, &tablenr))
+    {
+      /* There is no enough table bits, fall back to materialization. */
+      derived->change_refs_to_fields();
+      derived->set_materialized_derived();
+      goto exit_merge;
+    }
 
-  if (dt_select->options & OPTION_SCHEMA_TABLE)
-    parent_lex->options |= OPTION_SCHEMA_TABLE;
+    if (dt_select->leaf_tables.elements + tablenr > MAX_TABLES)
+    {
+      /* There is no enough table bits, fall back to materialization. */
+      derived->change_refs_to_fields();
+      derived->set_materialized_derived();
+      goto exit_merge;
+    }
 
-  parent_lex->cond_count+= dt_select->cond_count;
+    if (dt_select->options & OPTION_SCHEMA_TABLE)
+      parent_lex->options |= OPTION_SCHEMA_TABLE;
 
-  if (!derived->get_unit()->prepared)
-  {
-    dt_select->leaf_tables.empty();
-    make_leaves_list(dt_select->leaf_tables, derived, TRUE, 0);
-  } 
+    parent_lex->cond_count+= dt_select->cond_count;
 
-  if (!derived->merged_for_insert)
-  {  derived->nested_join= (NESTED_JOIN*) thd->calloc(sizeof(NESTED_JOIN));
+    if (!derived->get_unit()->prepared)
+    {
+      dt_select->leaf_tables.empty();
+      make_leaves_list(dt_select->leaf_tables, derived, TRUE, 0);
+    } 
+
+    derived->nested_join= (NESTED_JOIN*) thd->calloc(sizeof(NESTED_JOIN));
     if (!derived->nested_join)
     {
       res= TRUE;
@@ -467,14 +472,16 @@ bool mysql_derived_merge_for_insert(THD *thd, LEX *lex, TABLE_LIST *derived)
 
   if (derived->merged_for_insert)
     return FALSE;
-  /* It's a target view for an INSERT, create field translation only. */
-  if (!derived->updatable || derived->is_materialized_derived())
+  if (derived->is_materialized_derived())
   {
-    bool res= derived->create_field_translation(thd);
+    bool res=  mysql_derived_prepare(thd, lex, derived);
+    derived->select_lex->leaf_tables.push_back(derived);
     return res;
   }
   if (!derived->is_multitable())
   {
+    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. */
@@ -504,6 +511,9 @@ bool mysql_derived_merge_for_insert(THD *thd, LEX *lex, TABLE_LIST *derived)
   }
   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;
   }
@@ -609,7 +619,11 @@ bool mysql_derived_prepare(THD *thd, LEX *lex, TABLE_LIST *derived)
   bool res= FALSE;
 
   // Skip already prepared views/DT
-  if (!unit || unit->prepared || derived->merged_for_insert)
+  if (!unit || unit->prepared ||
+      (derived->merged_for_insert && 
+       !(derived->is_multitable() &&
+         (thd->lex->sql_command == SQLCOM_UPDATE_MULTI ||
+          thd->lex->sql_command == SQLCOM_DELETE_MULTI))))
     DBUG_RETURN(FALSE);
 
   Query_arena *arena= thd->stmt_arena, backup;

sql/sql_lex.cc

@@ -1604,6 +1604,7 @@ void st_select_lex::init_query()
   top_join_list.empty();
   join_list= &top_join_list;
   embedding= 0;
+  leaf_tables_prep.empty();
   leaf_tables.empty();
   item_list.empty();
   join= 0;
@@ -1672,6 +1673,7 @@ void st_select_lex::init_select()
   cond_value= having_value= Item::COND_UNDEF;
   inner_refs_list.empty();
   full_group_by_flag= 0;
+  is_prep_leaf_list_saved= FALSE;
   insert_tables= 0;
   merged_into= 0;
 }
@@ -3585,6 +3587,7 @@ void SELECT_LEX::mark_const_derived(bool empty)
   }
 }
 
+
 bool st_select_lex::save_leaf_tables(THD *thd)
 {
   Query_arena *arena= thd->stmt_arena, backup;
@@ -3609,6 +3612,33 @@ bool st_select_lex::save_leaf_tables(THD *thd)
 }
 
 
+bool st_select_lex::save_prep_leaf_tables(THD *thd)
+{
+  if (!thd->save_prep_leaf_list)
+    return 0;
+
+  Query_arena *arena= thd->stmt_arena, backup;
+  if (arena->is_conventional())
+    arena= 0;                                  
+  else
+    thd->set_n_backup_active_arena(arena, &backup);
+
+  List_iterator_fast<TABLE_LIST> li(leaf_tables);
+  TABLE_LIST *table;
+  while ((table= li++))
+  {
+    if (leaf_tables_prep.push_back(table))
+      return 1;
+  }
+  thd->lex->select_lex.is_prep_leaf_list_saved= TRUE; 
+  thd->save_prep_leaf_list= FALSE;
+  if (arena)
+    thd->restore_active_arena(arena, &backup);
+
+  return 0;
+}
+
+
 /**
   A routine used by the parser to decide whether we are specifying a full
   partitioning or if only partitions to add or to split.

sql/sql_lex.h

@@ -639,6 +639,8 @@ class st_select_lex: public st_select_lex_node
   */
   List<TABLE_LIST> leaf_tables;
   List<TABLE_LIST> leaf_tables_exec;
+  List<TABLE_LIST> leaf_tables_prep;
+  bool is_prep_leaf_list_saved;
   uint insert_tables;
   st_select_lex *merged_into; /* select which this select is merged into */
                               /* (not 0 only for views/derived tables)   */
@@ -899,6 +901,7 @@ class st_select_lex: public st_select_lex_node
   void mark_const_derived(bool empty);
 
   bool save_leaf_tables(THD *thd);
+  bool save_prep_leaf_tables(THD *thd);
 
 private:  
   /* current index hint kind. used in filling up index_hints */

sql/sql_prepare.cc

@@ -1269,8 +1269,9 @@ static int mysql_test_update(Prepared_statement *stmt,
     thd->fill_derived_tables() is false here for sure (because it is
     preparation of PS, so we even do not check it).
   */
-  if (table_list->handle_derived(thd->lex, DT_MERGE_FOR_INSERT) ||
-      table_list->handle_derived(thd->lex, DT_PREPARE))
+  if (table_list->handle_derived(thd->lex, DT_MERGE_FOR_INSERT))
+    goto error;
+  if (table_list->handle_derived(thd->lex, DT_PREPARE))
     goto error;
 
   if (!table_list->updatable)
@@ -1340,9 +1341,11 @@ static bool mysql_test_delete(Prepared_statement *stmt,
       open_tables(thd, &table_list, &table_count, 0))
     goto error;
 
-  if (mysql_handle_derived(thd->lex, DT_INIT) ||
-      mysql_handle_list_of_derived(thd->lex, table_list, DT_MERGE_FOR_INSERT) ||
-      mysql_handle_list_of_derived(thd->lex, table_list, DT_PREPARE))
+  if (mysql_handle_derived(thd->lex, DT_INIT))
+    goto error;
+  if (mysql_handle_derived(thd->lex, DT_MERGE_FOR_INSERT))
+    goto error;
+  if (mysql_handle_derived(thd->lex, DT_PREPARE))
     goto error;
 
   if (!table_list->updatable)

sql/sql_update.cc

@@ -1038,8 +1038,9 @@ int mysql_multi_update_prepare(THD *thd)
     call in setup_tables()).
   */
   //We need to merge for insert prior to prepare.
-  if (mysql_handle_list_of_derived(lex, table_list, DT_MERGE_FOR_INSERT))
-    DBUG_RETURN(1);
+  if (mysql_handle_derived(lex, DT_MERGE_FOR_INSERT))
+    DBUG_RETURN(TRUE);
+
   if (mysql_handle_derived(lex, DT_PREPARE))
     DBUG_RETURN(TRUE);
 
@@ -1237,6 +1238,9 @@ int mysql_multi_update_prepare(THD *thd)
     further check in multi_update::prepare whether to use record cache.
   */
   lex->select_lex.exclude_from_table_unique_test= FALSE;
+
+  if (lex->select_lex.save_prep_leaf_tables(thd))
+    DBUG_RETURN(TRUE);
  
   DBUG_RETURN (FALSE);
 }

sql/table.cc

@@ -5372,7 +5372,7 @@ void TABLE::use_index(int key_to_save)
   DBUG_ASSERT(!created && key_to_save < (int)s->keys);
   if (key_to_save >= 0)
     /* Save the given key. */
-    memcpy(key_info, key_info + key_to_save, sizeof(KEY));
+    memmove(key_info, key_info + key_to_save, sizeof(KEY));
   else
     /* Drop all keys; */
     i= 0;