BUG#20549: Fix missing memory initialization.

Some values were not initialized, causing Valgrind errors (and potential
random bugs):

 - NDB binlog thread thd->variables.pseudo_thread_id.
 - Table null bits.
 - Field bytes for columns with NULL values.


sql/ha_ndbcluster_binlog.cc:
  Fix initialization of thd->variables.pseudo_thread_id.
  Change double alloc_root() call to multi_alloc_root().
  Fix missing initialization of null bits.
sql/sql_class.cc:
  Do not read from the supplied record for NULL values, use the default
  value record instead.
  Otherwise we will get Valgrind errors about uninitialised values written
  to binlog, as NDB does not initialize the memory in records for NULL
  fields.

sql/ha_ndbcluster_binlog.cc

@@ -311,8 +311,10 @@ ndbcluster_binlog_open_table(THD *thd, NDB_SHARE *share,
   if (!reopen)
   {
     // allocate memory on ndb share so it can be reused after online alter table
-    share->record[0]= (byte*) alloc_root(&share->mem_root, table->s->rec_buff_length);
-    share->record[1]= (byte*) alloc_root(&share->mem_root, table->s->rec_buff_length);
+    (void)multi_alloc_root(&share->mem_root,
+                           &(share->record[0]), table->s->rec_buff_length,
+                           &(share->record[1]), table->s->rec_buff_length,
+                           NULL);
   }
   {
     my_ptrdiff_t row_offset= share->record[0] - table->record[0];
@@ -2159,6 +2161,9 @@ int ndb_add_binlog_index(THD *thd, void *_row)
     break;
   }
 
+  // Set all fields non-null.
+  if(binlog_index->s->null_bytes > 0)
+    bzero(binlog_index->record[0], binlog_index->s->null_bytes);
   binlog_index->field[0]->store(row.master_log_pos);
   binlog_index->field[1]->store(row.master_log_file,
                                 strlen(row.master_log_file),
@@ -3275,6 +3280,13 @@ pthread_handler_t ndb_binlog_thread_func(void *arg)
   thd= new THD; /* note that contructor of THD uses DBUG_ */
   THD_CHECK_SENTRY(thd);
 
+  /* We need to set thd->thread_id before thd->store_globals, or it will
+     set an invalid value for thd->variables.pseudo_thread_id.
+  */
+  pthread_mutex_lock(&LOCK_thread_count);
+  thd->thread_id= thread_id++;
+  pthread_mutex_unlock(&LOCK_thread_count);
+
   thd->thread_stack= (char*) &thd; /* remember where our stack is */
   if (thd->store_globals())
   {
@@ -3307,7 +3319,6 @@ pthread_handler_t ndb_binlog_thread_func(void *arg)
   pthread_detach_this_thread();
   thd->real_id= pthread_self();
   pthread_mutex_lock(&LOCK_thread_count);
-  thd->thread_id= thread_id++;
   threads.append(thd);
   pthread_mutex_unlock(&LOCK_thread_count);
   thd->lex->start_transaction_opt= 0;
@@ -3641,6 +3652,10 @@ pthread_handler_t ndb_binlog_thread_func(void *arg)
             injector::transaction::table tbl(table, TRUE);
             int ret= trans.use_table(::server_id, tbl);
             DBUG_ASSERT(ret == 0);
+
+            // Set all fields non-null.
+            if(table->s->null_bytes > 0)
+              bzero(table->record[0], table->s->null_bytes);
             table->field[0]->store((longlong)::server_id);
             table->field[1]->store((longlong)gci);
             trans.write_row(::server_id,

sql/sql_class.cc

@@ -2475,16 +2475,20 @@ my_size_t THD::pack_row(TABLE *table, MY_BITMAP const* cols, byte *row_data,
   int n_null_bytes= table->s->null_bytes;
   byte *ptr;
   uint i;
-  my_ptrdiff_t const offset= (my_ptrdiff_t) (record - (byte*)
-                                             table->record[0]);
+  my_ptrdiff_t const rec_offset= record - table->record[0];
+  my_ptrdiff_t const def_offset= table->s->default_values - table->record[0];
   memcpy(row_data, record, n_null_bytes);
   ptr= row_data+n_null_bytes;
 
   for (i= 0 ; (field= *p_field) ; i++, p_field++)
   {
     if (bitmap_is_set(cols,i))
+    {
+      my_ptrdiff_t const offset=
+        field->is_null(rec_offset) ? def_offset : rec_offset;
       ptr= (byte*)field->pack((char *) ptr, field->ptr + offset);
     }
+  }
   return (static_cast<my_size_t>(ptr - row_data));
 }