1 files changed, 52 insertions, 23 deletions

diff --git a/sql/item_func.h b/sql/item_func.h
index 80fa0b5d634..f562c87fe1c 100644
--- a/sql/item_func.h
+++ b/sql/item_func.h
@@ -1,7 +1,7 @@
 #ifndef ITEM_FUNC_INCLUDED
 #define ITEM_FUNC_INCLUDED
 /* Copyright (c) 2000, 2011, Oracle and/or its affiliates.
-   Copyright (c) 2009-2011 Monty Program Ab
+   Copyright (c) 2009, 2013, Monty Program Ab.
 
    This program is free software; you can redistribute it and/or modify
    it under the terms of the GNU General Public License as published by
@@ -39,6 +39,8 @@ protected:
     0 means get this number from first argument
   */
   uint allowed_arg_cols;
+  /* maybe_null can't be changed by parameters or used table state */
+  bool persistent_maybe_null;
 public:
   uint arg_count;
   table_map used_tables_cache, not_null_tables_cache;
@@ -58,19 +60,19 @@ public:
                   NOW_FUNC, TRIG_COND_FUNC,
                   SUSERVAR_FUNC, GUSERVAR_FUNC, COLLATE_FUNC,
                   EXTRACT_FUNC, CHAR_TYPECAST_FUNC, FUNC_SP, UDF_FUNC,
-                  NEG_FUNC, GSYSVAR_FUNC };
+                  NEG_FUNC, GSYSVAR_FUNC, DYNCOL_FUNC };
   enum optimize_type { OPTIMIZE_NONE,OPTIMIZE_KEY,OPTIMIZE_OP, OPTIMIZE_NULL,
                        OPTIMIZE_EQUAL };
   enum Type type() const { return FUNC_ITEM; }
   virtual enum Functype functype() const   { return UNKNOWN_FUNC; }
   Item_func(void):
-    allowed_arg_cols(1), arg_count(0)
+    allowed_arg_cols(1), persistent_maybe_null(0), arg_count(0)
   {
     with_sum_func= 0;
     with_field= 0;
   }
   Item_func(Item *a):
-    allowed_arg_cols(1), arg_count(1)
+    allowed_arg_cols(1), persistent_maybe_null(0), arg_count(1)
   {
     args= tmp_arg;
     args[0]= a;
@@ -78,7 +80,7 @@ public:
     with_field= a->with_field;
   }
   Item_func(Item *a,Item *b):
-    allowed_arg_cols(1), arg_count(2)
+    allowed_arg_cols(1), persistent_maybe_null(0), arg_count(2)
   {
     args= tmp_arg;
     args[0]= a; args[1]= b;
@@ -86,7 +88,7 @@ public:
     with_field= a->with_field || b->with_field;
   }
   Item_func(Item *a,Item *b,Item *c):
-    allowed_arg_cols(1)
+    allowed_arg_cols(1), persistent_maybe_null(0)
   {
     arg_count= 0;
     if ((args= (Item**) sql_alloc(sizeof(Item*)*3)))
@@ -98,7 +100,7 @@ public:
     }
   }
   Item_func(Item *a,Item *b,Item *c,Item *d):
-    allowed_arg_cols(1)
+    allowed_arg_cols(1), persistent_maybe_null(0)
   {
     arg_count= 0;
     if ((args= (Item**) sql_alloc(sizeof(Item*)*4)))
@@ -112,7 +114,7 @@ public:
     }
   }
   Item_func(Item *a,Item *b,Item *c,Item *d,Item* e):
-    allowed_arg_cols(1)
+    allowed_arg_cols(1), persistent_maybe_null(0)
   {
     arg_count= 5;
     if ((args= (Item**) sql_alloc(sizeof(Item*)*5)))
@@ -170,6 +172,18 @@ public:
 
   my_decimal *val_decimal(my_decimal *);
 
+  void fix_char_length_ulonglong(ulonglong max_char_length_arg)
+  {
+    ulonglong max_result_length= max_char_length_arg *
+                                 collation.collation->mbmaxlen;
+    if (max_result_length >= MAX_BLOB_WIDTH)
+    {
+      max_length= MAX_BLOB_WIDTH;
+      set_persist_maybe_null(1);
+    }
+    else
+      max_length= (uint32) max_result_length;
+  }
   bool agg_arg_charsets(DTCollation &c, Item **items, uint nitems,
                         uint flags, int item_sep)
   {
@@ -371,6 +385,11 @@ public:
     info.bool_function= &Item::restore_to_before_no_rows_in_result;
     walk(&Item::call_bool_func_processor, FALSE, (uchar*) &info);
   }
+  inline void set_persist_maybe_null(bool mb_null)
+  {
+    maybe_null= mb_null;
+    persistent_maybe_null= 1;
+  }
 };
 
 
@@ -586,7 +605,7 @@ public:
   }
   double val_real();
   enum_field_types field_type() const { return MYSQL_TYPE_DOUBLE; }
-  void fix_length_and_dec() { maybe_null= 1; }
+  void fix_length_and_dec() { set_persist_maybe_null(1); }
   const char *func_name() const { return "double_typecast"; }
   virtual void print(String *str, enum_query_type query_type);
 };
@@ -727,7 +746,7 @@ class Item_dec_func :public Item_real_func
   void fix_length_and_dec()
   {
     decimals=NOT_FIXED_DEC; max_length=float_length(decimals);
-    maybe_null=1;
+    set_persist_maybe_null(1);
   }
 };
 
@@ -1059,7 +1078,7 @@ public:
   Item_func_coercibility(Item *a) :Item_int_func(a) {}
   longlong val_int();
   const char *func_name() const { return "coercibility"; }
-  void fix_length_and_dec() { max_length=10; maybe_null= 0; }
+  void fix_length_and_dec() { max_length=10; set_persist_maybe_null(0); }
   table_map not_null_tables() const { return 0; }
 };
 
@@ -1201,6 +1220,7 @@ public:
   const char *func_name() const { return "last_insert_id"; }
   void fix_length_and_dec()
   {
+    unsigned_flag= TRUE;
     if (arg_count)
       max_length= args[0]->max_length;
     unsigned_flag=1;
@@ -1221,7 +1241,7 @@ public:
   {}
   longlong val_int();
   const char *func_name() const { return "benchmark"; }
-  void fix_length_and_dec() { max_length=1; maybe_null=0; }
+  void fix_length_and_dec() { max_length=1; set_persist_maybe_null(0); }
   virtual void print(String *str, enum_query_type query_type);
   bool check_vcol_func_processor(uchar *int_arg) 
   {
@@ -1474,7 +1494,7 @@ public:
   double val_real() { DBUG_ASSERT(fixed == 1); null_value= 1; return 0.0; }
   longlong val_int() { DBUG_ASSERT(fixed == 1); null_value=1; return 0; }
   enum Item_result result_type () const { return STRING_RESULT; }
-  void fix_length_and_dec() { maybe_null=1; max_length=0; }
+  void fix_length_and_dec() { set_persist_maybe_null(1); max_length=0; }
 };
 
 #endif /* HAVE_DLOPEN */
@@ -1495,7 +1515,7 @@ class Item_func_get_lock :public Item_int_func
   Item_func_get_lock(Item *a,Item *b) :Item_int_func(a,b) {}
   longlong val_int();
   const char *func_name() const { return "get_lock"; }
-  void fix_length_and_dec() { max_length=1; maybe_null=1;}
+  void fix_length_and_dec() { max_length=1; set_persist_maybe_null(1);}
   bool check_vcol_func_processor(uchar *int_arg) 
   {
     return trace_unsupported_by_check_vcol_func_processor(func_name());
@@ -1509,7 +1529,7 @@ public:
   Item_func_release_lock(Item *a) :Item_int_func(a) {}
   longlong val_int();
   const char *func_name() const { return "release_lock"; }
-  void fix_length_and_dec() { max_length=1; maybe_null=1;}
+  void fix_length_and_dec() { max_length=1; set_persist_maybe_null(1);}
   bool check_vcol_func_processor(uchar *int_arg) 
   {
     return trace_unsupported_by_check_vcol_func_processor(func_name());
@@ -1527,7 +1547,7 @@ public:
   Item_master_pos_wait(Item *a,Item *b, Item *c, Item *d) :Item_int_func(a,b,c,d) {}
   longlong val_int();
   const char *func_name() const { return "master_pos_wait"; }
-  void fix_length_and_dec() { max_length=21; maybe_null=1;}
+  void fix_length_and_dec() { max_length=21; set_persist_maybe_null(1);}
   bool check_vcol_func_processor(uchar *int_arg) 
   {
     return trace_unsupported_by_check_vcol_func_processor(func_name());
@@ -1744,7 +1764,8 @@ public:
   Item_func_inet_aton(Item *a) :Item_int_func(a) {}
   longlong val_int();
   const char *func_name() const { return "inet_aton"; }
-  void fix_length_and_dec() { decimals= 0; max_length= 21; maybe_null= 1; unsigned_flag= 1;}
+  void fix_length_and_dec()
+  { decimals= 0; max_length= 21; set_persist_maybe_null(1); unsigned_flag= 1; }
 };
 
 
@@ -1813,7 +1834,8 @@ public:
   Item_func_is_free_lock(Item *a) :Item_int_func(a) {}
   longlong val_int();
   const char *func_name() const { return "is_free_lock"; }
-  void fix_length_and_dec() { decimals=0; max_length=1; maybe_null=1;}
+  void fix_length_and_dec()
+  { decimals= 0; max_length= 1; set_persist_maybe_null(1); }
   bool check_vcol_func_processor(uchar *int_arg) 
   {
     return trace_unsupported_by_check_vcol_func_processor(func_name());
@@ -1827,7 +1849,8 @@ public:
   Item_func_is_used_lock(Item *a) :Item_int_func(a) {}
   longlong val_int();
   const char *func_name() const { return "is_used_lock"; }
-  void fix_length_and_dec() { decimals=0; max_length=10; maybe_null=1;}
+  void fix_length_and_dec()
+  { decimals= 0; max_length= 10; set_persist_maybe_null(1);}
   bool check_vcol_func_processor(uchar *int_arg) 
   {
     return trace_unsupported_by_check_vcol_func_processor(func_name());
@@ -1850,7 +1873,7 @@ public:
   Item_func_row_count() :Item_int_func() {}
   longlong val_int();
   const char *func_name() const { return "row_count"; }
-  void fix_length_and_dec() { decimals= 0; maybe_null=0; }
+  void fix_length_and_dec() { decimals= 0; set_persist_maybe_null(0); }
   bool check_vcol_func_processor(uchar *int_arg) 
   {
 
@@ -1887,7 +1910,8 @@ private:
   bool init_result_field(THD *thd);
 
 protected:
-  bool is_expensive_processor(uchar *arg) { return TRUE; }
+  bool is_expensive_processor(uchar *arg)
+  { return is_expensive(); }
   
 public:
 
@@ -1966,7 +1990,7 @@ public:
 
   bool fix_fields(THD *thd, Item **ref);
   void fix_length_and_dec(void);
-  bool is_expensive() { return 1; }
+  bool is_expensive();
 
   inline Field *get_sp_result_field()
   {
@@ -1990,7 +2014,7 @@ public:
   Item_func_found_rows() :Item_int_func() {}
   longlong val_int();
   const char *func_name() const { return "found_rows"; }
-  void fix_length_and_dec() { decimals= 0; maybe_null=0; }
+  void fix_length_and_dec() { decimals= 0; set_persist_maybe_null(0); }
   bool check_vcol_func_processor(uchar *int_arg) 
   {
     return trace_unsupported_by_check_vcol_func_processor(func_name());
@@ -2033,6 +2057,11 @@ public:
   enum_field_types field_type() const { return last_value->field_type(); }
   bool const_item() const { return 0; }
   void evaluate_sideeffects();
+  void update_used_tables()
+  {
+    Item_func::update_used_tables();
+    maybe_null= last_value->maybe_null;
+  }
 };