fixed BUG#1180 (changing WHERE clause of prepared statements by optimisation)

sql/item.h

@@ -120,6 +120,9 @@ class Item {
      Constructor used by Item_field, Item_ref & agregate (sum) functions.
      Used for duplicating lists in processing queries with temporary
      tables
+     Also it used for Item_cond_and/Item_cond_or for creating
+     top AND/OR ctructure of WHERE clause to protect it of
+     optimisation changes in prepared statements
   */
   Item(THD *thd, Item &item);
   virtual ~Item() { name=0; }		/*lint -e1509 */
@@ -184,6 +187,7 @@ class Item {
   virtual void save_in_result_field(bool no_conversions) {}
   virtual void no_rows_in_result() {}
   virtual Item *copy_or_same(THD *thd) { return this; }
+  virtual Item *copy_andor_structure(THD *thd) { return this; }
   virtual Item *real_item() { return this; }
   virtual Item *get_tmp_table_item(THD *thd) { return copy_or_same(thd); }
 
@@ -541,7 +545,7 @@ class Item_result_field :public Item	/* Item with result field */
 public:
   Field *result_field;				/* Save result here */
   Item_result_field() :result_field(0) {}
-  // Constructor used for Item_sum (see Item comment)
+  // Constructor used for Item_sum/Item_cond_and/or (see Item comment)
   Item_result_field(THD *thd, Item_result_field &item):
     Item(thd, item), result_field(item.result_field)
   {}

sql/item_cmpfunc.cc

@@ -1549,6 +1549,31 @@ longlong Item_func_bit_and::val_int()
   return (longlong) (arg1 & arg2);
 }
 
+Item_cond::Item_cond(THD *thd, Item_cond &item)
+  :Item_bool_func(thd, item),
+   abort_on_null(item.abort_on_null),
+   and_tables_cache(item.and_tables_cache)
+{
+  /*
+    here should be following text:
+
+  List_iterator_fast<Item*> li(item.list);
+  while(Item *it= li++)
+    list.push_back(it);
+
+    but it do not need,
+    because this constructor used only for AND/OR and
+    argument list will be copied by copy_andor_arguments call
+  */
+
+}
+
+void Item_cond::copy_andor_arguments(THD *thd, Item_cond *item)
+{
+  List_iterator_fast<Item> li(item->list);
+  while(Item *it= li++)
+    list.push_back(it->copy_andor_structure(thd));
+}
 
 bool
 Item_cond::fix_fields(THD *thd, TABLE_LIST *tables, Item **ref)

sql/item_cmpfunc.h

@@ -82,6 +82,7 @@ class Item_bool_func :public Item_int_func
   Item_bool_func() :Item_int_func() {}
   Item_bool_func(Item *a) :Item_int_func(a) {}
   Item_bool_func(Item *a,Item *b) :Item_int_func(a,b) {}
+  Item_bool_func(THD *thd, Item_bool_func &item) :Item_int_func(thd, item) {}
   void fix_length_and_dec() { decimals=0; max_length=1; }
 };
 
@@ -115,8 +116,8 @@ class Item_bool_func2 :public Item_int_func
   String tmp_value1,tmp_value2;
 
 public:
-  Item_bool_func2(Item *a,Item *b):
-    Item_int_func(a,b), cmp(tmp_arg, tmp_arg+1) {}
+  Item_bool_func2(Item *a,Item *b)
+    :Item_int_func(a,b), cmp(tmp_arg, tmp_arg+1) {}
   void fix_length_and_dec();
   void set_cmp_func()
   {
@@ -158,7 +159,7 @@ class Item_func_not :public Item_bool_func
 class Item_func_eq :public Item_bool_rowready_func2
 {
 public:
-  Item_func_eq(Item *a,Item *b) :Item_bool_rowready_func2(a,b) {};
+  Item_func_eq(Item *a,Item *b) :Item_bool_rowready_func2(a,b) {}
   longlong val_int();
   enum Functype functype() const { return EQ_FUNC; }
   enum Functype rev_functype() const { return EQ_FUNC; }
@@ -791,8 +792,13 @@ class Item_cond :public Item_bool_func
 public:
   /* Item_cond() is only used to create top level items */
   Item_cond() : Item_bool_func(), abort_on_null(1) { const_item_cache=0; }
-  Item_cond(Item *i1,Item *i2) :Item_bool_func(), abort_on_null(0)
-  { list.push_back(i1); list.push_back(i2); }
+  Item_cond(Item *i1,Item *i2) 
+    :Item_bool_func(), abort_on_null(0)
+  {
+    list.push_back(i1);
+    list.push_back(i2);
+  }
+  Item_cond(THD *thd, Item_cond &item);
   ~Item_cond() { list.delete_elements(); }
   bool add(Item *item) { return list.push_back(item); }
   bool fix_fields(THD *, struct st_table_list *, Item **ref);
@@ -805,6 +811,7 @@ class Item_cond :public Item_bool_func
   void split_sum_func(Item **ref_pointer_array, List<Item> &fields);
   friend int setup_conds(THD *thd,TABLE_LIST *tables,COND **conds);
   void top_level_item() { abort_on_null=1; }
+  void copy_andor_arguments(THD *thd, Item_cond *item);
 
   bool walk(Item_processor processor, byte *arg);
 };
@@ -815,9 +822,17 @@ class Item_cond_and :public Item_cond
 public:
   Item_cond_and() :Item_cond() {}
   Item_cond_and(Item *i1,Item *i2) :Item_cond(i1,i2) {}
+  Item_cond_and(THD *thd, Item_cond_and &item) :Item_cond(thd, item) {}
   enum Functype functype() const { return COND_AND_FUNC; }
   longlong val_int();
   const char *func_name() const { return "and"; }
+  Item* copy_andor_structure(THD *thd)
+  {
+    Item_cond_and *item;
+    if((item= new Item_cond_and(thd, *this)))
+       item->copy_andor_arguments(thd, this);
+    return item;
+  }
 };
 
 class Item_cond_or :public Item_cond
@@ -825,10 +840,18 @@ class Item_cond_or :public Item_cond
 public:
   Item_cond_or() :Item_cond() {}
   Item_cond_or(Item *i1,Item *i2) :Item_cond(i1,i2) {}
+  Item_cond_or(THD *thd, Item_cond_or &item) :Item_cond(thd, item) {}
   enum Functype functype() const { return COND_OR_FUNC; }
   longlong val_int();
   const char *func_name() const { return "or"; }
   table_map not_null_tables() const { return and_tables_cache; }
+  Item* copy_andor_structure(THD *thd)
+  {
+    Item_cond_or *item;
+    if((item= new Item_cond_or(thd, *this)))
+      item->copy_andor_arguments(thd, this);
+    return item;
+  }
 };
 
 

sql/item_func.cc

@@ -134,6 +134,27 @@ Item_func::Item_func(List<Item> &list)
   set_arguments(list);
 }
 
+Item_func::Item_func(THD *thd, Item_func &item)
+  :Item_result_field(thd, item),
+   allowed_arg_cols(item.allowed_arg_cols),
+   arg_count(item.arg_count),
+   used_tables_cache(item.used_tables_cache),
+   not_null_tables_cache(item.not_null_tables_cache),
+   const_item_cache(item.const_item_cache)
+{
+  if (arg_count)
+  {
+    if (arg_count <=2)
+      args= tmp_arg;
+    else
+    {
+      if (!(args=(Item**) thd->alloc(sizeof(Item*)*arg_count)))
+	return;
+    }
+    memcpy((char*) args, (char*) item.args, sizeof(Item*)*arg_count);
+  }
+}
+
 
 /*
   Resolve references to table column for a function and it's argument

sql/item_func.h

@@ -104,6 +104,8 @@ class Item_func :public Item_result_field
     }
   }
   Item_func(List<Item> &list);
+  // Constructor used for Item_cond_and/or (see Item comment)
+  Item_func(THD *thd, Item_func &item);
   ~Item_func() {} /* Nothing to do; Items are freed automaticly */
   bool fix_fields(THD *,struct st_table_list *, Item **ref);
   table_map used_tables() const;
@@ -196,6 +198,7 @@ class Item_int_func :public Item_func
   Item_int_func(Item *a,Item *b) :Item_func(a,b) { max_length=21; }
   Item_int_func(Item *a,Item *b,Item *c) :Item_func(a,b,c) { max_length=21; }
   Item_int_func(List<Item> &list) :Item_func(list) { max_length=21; }
+  Item_int_func(THD *thd, Item_int_func &item) :Item_func(thd, item) {}
   double val() { return (double) val_int(); }
   String *val_str(String*str);
   enum Item_result result_type () const { return INT_RESULT; }

sql/sql_lex.cc

@@ -982,6 +982,7 @@ void st_select_lex::init_query()
   cond_count= with_wild= 0;
   ref_pointer_array= 0;
   select_n_having_items= 0;
+  prep_where= 0;
 }
 
 void st_select_lex::init_select()

sql/sql_lex.h

@@ -339,6 +339,7 @@ class st_select_lex: public st_select_lex_node
 public:
   char *db, *db1, *table1, *db2, *table2;      	/* For outer join using .. */
   Item *where, *having;                         /* WHERE & HAVING clauses */
+  Item *prep_where; /* saved WHERE clause for prepared statement processing */
   enum olap_type olap;
   SQL_LIST	      table_list, group_list;   /* FROM & GROUP BY clauses */
   List<Item>          item_list; /* list of fields & expressions */

sql/sql_prepare.cc

@@ -873,11 +873,21 @@ bool mysql_stmt_prepare(THD *thd, char *packet, uint packet_length)
 
   if (!(specialflag & SPECIAL_NO_PRIOR))
     my_pthread_setprio(pthread_self(),WAIT_PRIOR);
+
+  // save WHERE clause pointers to avoid damaging they by optimisation
+  for (SELECT_LEX *sl= thd->lex.all_selects_list;
+       sl;
+       sl= sl->next_select_in_list())
+  {
+    sl->prep_where= sl->where;
+  }
+
   
   if (init_param_items(&stmt))
     goto err;
+
   
-  stmt.mem_root= stmt.thd->mem_root;  
+  stmt.mem_root= stmt.thd->mem_root;
   tree_insert(&thd->prepared_statements, (void *)&stmt, 0, (void *)0);
   thd->mem_root= thd_root; // restore main mem_root
   DBUG_RETURN(0);
@@ -919,6 +929,17 @@ void mysql_stmt_execute(THD *thd, char *packet)
 
   LEX thd_lex= thd->lex;
   thd->lex= stmt->lex;
+  
+  for (SELECT_LEX *sl= stmt->lex.all_selects_list;
+       sl;
+       sl= sl->next_select_in_list())
+  {
+    // copy WHERE clause pointers to avoid damaging they by optimisation
+    if (sl->prep_where)
+      sl->where= sl->prep_where->copy_andor_structure(thd);
+    // force allocation new JOIN for this mem_root (for safety)
+    sl->join= 0;
+  }
   init_stmt_execute(stmt);
 
   if (stmt->param_count && setup_params_data(stmt))

tests/client_test.c

@@ -1839,6 +1839,85 @@ session_id  char(9) NOT NULL, \
   mysql_stmt_close(stmt);
 }
 
+/*
+  test BUG#1180 (optimized away part of WHERE clause)
+*/
+static void test_bug1180()
+{
+  MYSQL_STMT *stmt;
+  int rc;
+  MYSQL_BIND bind[1];
+  ulong length[1];
+  char szData[11];
+  int nData=1;
+
+  myheader("test_select_bug");
+
+  rc = mysql_query(mysql,"DROP TABLE IF EXISTS test_select");
+  myquery(rc);
+
+  rc = mysql_query(mysql,"CREATE TABLE test_select(session_id  char(9) NOT NULL)");
+  myquery(rc);
+  rc = mysql_query(mysql,"INSERT INTO test_select VALUES (\"abc\")");
+  myquery(rc);
+
+  strmov(query,"SELECT * FROM test_select WHERE ?=\"1111\" and session_id = \"abc\"");
+  stmt = mysql_prepare(mysql, query, strlen(query));
+  mystmt_init(stmt);
+
+  verify_param_count(stmt,1);
+
+  strmov(szData,(char *)"abc");
+  bind[0].buffer_type=FIELD_TYPE_STRING;
+  bind[0].buffer=(char *)szData;
+  bind[0].buffer_length= 10;
+  bind[0].length= &length[0];
+  length[0]= 3;
+  bind[0].is_null=0;
+
+  rc = mysql_bind_param(stmt,bind);
+  mystmt(stmt, rc);
+
+  rc = mysql_execute(stmt);
+  mystmt(stmt, rc);
+
+  myassert(my_process_stmt_result(stmt) == 0);
+
+  strmov(szData,(char *)"1111");
+  bind[0].buffer_type=FIELD_TYPE_STRING;
+  bind[0].buffer=(char *)szData;
+  bind[0].buffer_length= 10;
+  bind[0].length= &length[0];
+  length[0]= 4;
+  bind[0].is_null=0;
+
+  rc = mysql_bind_param(stmt,bind);
+  mystmt(stmt, rc);
+
+  rc = mysql_execute(stmt);
+  mystmt(stmt, rc);
+
+  myassert(my_process_stmt_result(stmt) == 1);
+
+  strmov(szData,(char *)"abc");
+  bind[0].buffer_type=FIELD_TYPE_STRING;
+  bind[0].buffer=(char *)szData;
+  bind[0].buffer_length= 10;
+  bind[0].length= &length[0];
+  length[0]= 3;
+  bind[0].is_null=0;
+
+  rc = mysql_bind_param(stmt,bind);
+  mystmt(stmt, rc);
+
+  rc = mysql_execute(stmt);
+  mystmt(stmt, rc);
+
+  myassert(my_process_stmt_result(stmt) == 0);
+
+  mysql_stmt_close(stmt);
+}
+
 /********************************************************
 * to test simple select show                            *
 *********************************************************/
@@ -7898,6 +7977,7 @@ int main(int argc, char **argv)
     test_sqlmode();         /* test for SQL_MODE */
     test_ts();              /* test for timestamp BR#819 */
     test_bug1115();         /* BUG#1115 */
+    test_bug1180();         /* BUG#1180 */
 
     end_time= time((time_t *)0);
     total_time+= difftime(end_time, start_time);