Fix for LP#571200 MySQL Bug#32426: FederatedX corrupt ORDER BY with TEXT

Patch taken from lp:~capttofu/maria/bug_571200 (originally for MariaDB 5.3, but adapted for 5.1)

mysql-test/suite/federated/federated_server.result

@@ -213,7 +213,7 @@ id	name
 alter server s1 options (database 'db_bogus');
 flush tables;
 select * from federated.t1;
-ERROR 42000: Got error: 1044 : Access denied for user 'test_fed'@'localhost' to database 'db_bogus'
+ERROR 42000: Received error: 1044 : Access denied for user 'test_fed'@'localhost' to database 'db_bogus'
 drop server if exists 's1';
 ERROR 42000: Access denied; you need the SUPER privilege for this operation
 create server 's1' foreign data wrapper 'mysql' options

storage/federatedx/federatedx_io_mysql.cc

-/* 
+/*
 Copyright (c) 2007, Antony T Curtis
 All rights reserved.
 
@@ -51,6 +51,12 @@ typedef struct federatedx_savepoint
   uint  flags;
 } SAVEPT;
 
+struct mysql_position
+{
+  MYSQL_RES* result;
+  MYSQL_ROW_OFFSET offset;
+};
+
 
 class federatedx_io_mysql :public federatedx_io
 {
@@ -76,16 +82,16 @@ class federatedx_io_mysql :public federatedx_io
 
   virtual int error_code();
   virtual const char *error_str();
-  
+
   void reset();
   int commit();
   int rollback();
-  
+
   int savepoint_set(ulong sp);
   ulong savepoint_release(ulong sp);
   ulong savepoint_rollback(ulong sp);
   void savepoint_restrict(ulong sp);
-  
+
   ulong last_savepoint() const;
   ulong actual_savepoint() const;
   bool is_autocommit() const;
@@ -94,7 +100,7 @@ class federatedx_io_mysql :public federatedx_io
                       uint table_name_length, uint flag);
 
   /* resultset operations */
-  
+
   virtual void free_result(FEDERATEDX_IO_RESULT *io_result);
   virtual unsigned int get_num_fields(FEDERATEDX_IO_RESULT *io_result);
   virtual my_ulonglong get_num_rows(FEDERATEDX_IO_RESULT *io_result);
@@ -104,6 +110,12 @@ class federatedx_io_mysql :public federatedx_io
                                       unsigned int column);
   virtual bool is_column_null(const FEDERATEDX_IO_ROW *row,
                               unsigned int column) const;
+
+  virtual size_t get_ref_length() const;
+  virtual void mark_position(FEDERATEDX_IO_RESULT *io_result,
+                             void *ref);
+  virtual int seek_position(FEDERATEDX_IO_RESULT **io_result,
+                            const void *ref);
 };
 
 
@@ -466,14 +478,13 @@ const char *federatedx_io_mysql::error_str()
   return mysql_error(&mysql);
 }
 
-
 FEDERATEDX_IO_RESULT *federatedx_io_mysql::store_result()
 {
   FEDERATEDX_IO_RESULT *result;
   DBUG_ENTER("federatedx_io_mysql::store_result");
-  
+
   result= (FEDERATEDX_IO_RESULT *) mysql_store_result(&mysql);
-  
+
   DBUG_RETURN(result);
 }
 
@@ -590,3 +601,45 @@ bool federatedx_io_mysql::table_metadata(ha_statistics *stats,
   free_result(result);
   return 1;
 }
+
+
+
+size_t federatedx_io_mysql::get_ref_length() const
+{
+  return sizeof(mysql_position);
+}
+
+
+void federatedx_io_mysql::mark_position(FEDERATEDX_IO_RESULT *io_result,
+                                        void *ref)
+{
+  MYSQL_ROWS *tmp= 0;
+  mysql_position& pos= *reinterpret_cast<mysql_position*>(ref);
+  pos.result= (MYSQL_RES *) io_result;
+
+  if (pos.result && pos.result->data)
+  {
+    for (tmp= pos.result->data->data;
+         tmp && (tmp->next != pos.result->data_cursor);
+         tmp= tmp->next)
+    {}
+  }
+
+  pos.offset= tmp;
+}
+
+int federatedx_io_mysql::seek_position(FEDERATEDX_IO_RESULT **io_result,
+                                       const void *ref)
+{
+  const mysql_position& pos= *reinterpret_cast<const mysql_position*>(ref);
+
+  if (!pos.result || !pos.offset)
+    return HA_ERR_END_OF_FILE;
+
+  pos.result->current_row= 0;
+  pos.result->data_cursor= pos.offset;
+  *io_result= (FEDERATEDX_IO_RESULT*) pos.result;
+
+  return 0;
+}
+

storage/federatedx/federatedx_io_null.cc

@@ -96,6 +96,11 @@ class federatedx_io_null :public federatedx_io
                                       unsigned int column);
   virtual bool is_column_null(const FEDERATEDX_IO_ROW *row,
                               unsigned int column) const;
+  virtual size_t get_ref_length() const;
+  virtual void mark_position(FEDERATEDX_IO_RESULT *io_result,
+                             void *ref);
+  virtual int seek_position(FEDERATEDX_IO_RESULT **io_result,
+                            const void *ref);
 };
 
 
@@ -275,3 +280,20 @@ bool federatedx_io_null::table_metadata(ha_statistics *stats,
 
   return 0;
 }
+
+size_t federatedx_io_null::get_ref_length() const
+{
+  return sizeof(int);
+}
+
+
+void federatedx_io_null::mark_position(FEDERATEDX_IO_RESULT *io_result,
+                                       void *ref)
+{
+}
+
+int federatedx_io_null::seek_position(FEDERATEDX_IO_RESULT **io_result,
+                                      const void *ref)
+{
+  return 0;
+}

storage/federatedx/ha_federatedx.h

-/* 
-Copyright (c) 2008, Patrick Galbraith 
+/*
+Copyright (c) 2008, Patrick Galbraith
 All rights reserved.
 
 Redistribution and use in source and binary forms, with or without
@@ -43,7 +43,7 @@ class federatedx_io;
 typedef struct st_fedrated_server {
   MEM_ROOT mem_root;
   uint use_count, io_count;
-  
+
   uchar *key;
   uint key_length;
 
@@ -74,10 +74,10 @@ typedef struct st_fedrated_server {
 
 #include <mysql.h>
 
-/* 
+/*
   handler::print_error has a case statement for error numbers.
-  This value is (10000) is far out of range and will envoke the 
-  default: case.  
+  This value is (10000) is far out of range and will envoke the
+  default: case.
   (Current error range is 120-159 from include/my_base.h)
 */
 #define HA_FEDERATEDX_ERROR_WITH_REMOTE_SYSTEM 10000
@@ -158,7 +158,7 @@ class federatedx_io
   const char * get_database() const { return server->database; }
   ushort       get_port() const     { return server->port; }
   const char * get_socket() const   { return server->socket; }
-  
+
   static bool handles_scheme(const char *scheme);
   static federatedx_io *construct(MEM_ROOT *server_root,
                                   FEDERATEDX_SERVER *server);
@@ -167,7 +167,7 @@ class federatedx_io
   { return alloc_root(mem_root, size); }
   static void operator delete(void *ptr, size_t size)
   { TRASH(ptr, size); }
-    
+
   virtual int query(const char *buffer, uint length)=0;
   virtual FEDERATEDX_IO_RESULT *store_result()=0;
 
@@ -178,25 +178,25 @@ class federatedx_io
 
   virtual int error_code()=0;
   virtual const char *error_str()=0;
-  
+
   virtual void reset()=0;
   virtual int commit()=0;
   virtual int rollback()=0;
-  
+
   virtual int savepoint_set(ulong sp)=0;
   virtual ulong savepoint_release(ulong sp)=0;
   virtual ulong savepoint_rollback(ulong sp)=0;
   virtual void savepoint_restrict(ulong sp)=0;
-  
+
   virtual ulong last_savepoint() const=0;
   virtual ulong actual_savepoint() const=0;
   virtual bool is_autocommit() const=0;
 
   virtual bool table_metadata(ha_statistics *stats, const char *table_name,
                               uint table_name_length, uint flag) = 0;
-  
+
   /* resultset operations */
-  
+
   virtual void free_result(FEDERATEDX_IO_RESULT *io_result)=0;
   virtual unsigned int get_num_fields(FEDERATEDX_IO_RESULT *io_result)=0;
   virtual my_ulonglong get_num_rows(FEDERATEDX_IO_RESULT *io_result)=0;
@@ -206,6 +206,13 @@ class federatedx_io
                                       unsigned int column)=0;
   virtual bool is_column_null(const FEDERATEDX_IO_ROW *row,
                               unsigned int column) const=0;
+
+  virtual size_t get_ref_length() const=0;
+  virtual void mark_position(FEDERATEDX_IO_RESULT *io_result,
+                             void *ref)=0;
+  virtual int seek_position(FEDERATEDX_IO_RESULT **io_result,
+                            const void *ref)=0;
+
 };
 
 
@@ -215,12 +222,12 @@ class federatedx_txn
   ulong savepoint_level;
   ulong savepoint_stmt;
   ulong savepoint_next;
-  
+
   void release_scan();
 public:
   federatedx_txn();
   ~federatedx_txn();
-  
+
   bool has_connections() const { return txn_list != NULL; }
   bool in_transaction() const { return savepoint_next != 0; }
   int acquire(FEDERATEDX_SHARE *share, bool readonly, federatedx_io **io);
@@ -254,8 +261,12 @@ class ha_federatedx: public handler
   federatedx_txn *txn;
   federatedx_io *io;
   FEDERATEDX_IO_RESULT *stored_result;
+  /**
+      Array of all stored results we get during a query execution.
+  */
+  DYNAMIC_ARRAY results;
+  bool position_called;
   uint fetch_num; // stores the fetch num
-  FEDERATEDX_IO_OFFSET current_position;  // Current position used by ::position()
   int remote_error_number;
   char remote_error_buf[FEDERATEDX_QUERY_BUFFER_SIZE];
   bool ignore_duplicates, replace_duplicates;
@@ -269,7 +280,7 @@ class ha_federatedx: public handler
   */
   uint convert_row_to_internal_format(uchar *buf, FEDERATEDX_IO_ROW *row,
                                       FEDERATEDX_IO_RESULT *result);
-  bool create_where_from_key(String *to, KEY *key_info, 
+  bool create_where_from_key(String *to, KEY *key_info,
                              const key_range *start_key,
                              const key_range *end_key,
                              bool records_in_range, bool eq_range);
@@ -348,18 +359,18 @@ class ha_federatedx: public handler
     Talk to Kostja about this - how to get the
     number of rows * ...
     disk scan time on other side (block size, size of the row) + network time ...
-    The reason for "records * 1000" is that such a large number forces 
+    The reason for "records * 1000" is that such a large number forces
     this to use indexes "
   */
   double scan_time()
   {
     DBUG_PRINT("info", ("records %lu", (ulong) stats.records));
-    return (double)(stats.records*1000); 
+    return (double)(stats.records*1000);
   }
   /*
     The next method will never be called if you do not implement indexes.
   */
-  double read_time(uint index, uint ranges, ha_rows rows) 
+  double read_time(uint index, uint ranges, ha_rows rows)
   {
     /*
       Per Brian, this number is bugus, but this method must be implemented,