Copied patch for BUG#15588 (BUG#16621) from 5.0 into 5.1-release.

sql/field.cc

@@ -5880,7 +5880,7 @@ int Field_string::store(const char *from,uint length,CHARSET_INFO *cs)
                                                     field_length/
                                                     field_charset->mbmaxlen,
                                                     &well_formed_error);
-  memcpy(ptr,from,copy_length);
+  memmove(ptr,from,copy_length);
 
   /* Append spaces if the string was shorter than the field. */
   if (copy_length < field_length)
@@ -6296,7 +6296,7 @@ int Field_varstring::store(const char *from,uint length,CHARSET_INFO *cs)
 						    field_length/
 						    field_charset->mbmaxlen,
                                                     &well_formed_error);
-  memcpy(ptr + length_bytes, from, copy_length);
+  memmove(ptr + length_bytes, from, copy_length);
   if (length_bytes == 1)
     *ptr= (uchar) copy_length;
   else

sql/sp_head.cc

@@ -105,21 +105,27 @@ sp_get_item_value(Item *item, String *str)
 
   case STRING_RESULT:
     {
-      char buf_holder[STRING_BUFFER_USUAL_SIZE];
-      String buf(buf_holder, sizeof(buf_holder), &my_charset_latin1);
       String *result= item->val_str(str);
       
       if (!result)
         return NULL;
       
-      buf.append('_');
-      buf.append(result->charset()->csname);
-      buf.append('\'');
-      buf.append(*result);
-      buf.append('\'');
-      str->copy(buf);
-
-      return str;
+      {
+        char buf_holder[STRING_BUFFER_USUAL_SIZE];
+        String buf(buf_holder, sizeof (buf_holder), result->charset());
+      
+        /* We must reset length of the buffer, because of String specificity. */
+        buf.length(0);
+      
+        buf.append('_');
+        buf.append(result->charset()->csname);
+        buf.append('\'');
+        buf.append(*result);
+        buf.append('\'');
+        str->copy(buf);
+      
+        return str;
+      }
     }
 
   case ROW_RESULT:
@@ -3076,9 +3082,16 @@ sp_instr_set_case_expr::exec_core(THD *thd, uint *nextp)
 void
 sp_instr_set_case_expr::print(String *str)
 {
-  str->append(STRING_WITH_LEN("set_case_expr "));
+  const char CASE_EXPR_TAG[]= "set_case_expr ";
+  const int CASE_EXPR_TAG_LEN= sizeof(CASE_EXPR_TAG) - 1;
+  const int INT_STRING_MAX_LEN= 10;
+
+  /* We must call reserve(), because qs_append() doesn't care about memory. */
+  str->reserve(CASE_EXPR_TAG_LEN + INT_STRING_MAX_LEN + 2);
+
+  str->qs_append(CASE_EXPR_TAG, CASE_EXPR_TAG_LEN);
   str->qs_append(m_case_expr_id);
-  str->append(' ');
+  str->qs_append(' ');
   m_case_expr->print(str);
 }