Bug# 13847885 - PURGING STALLS WHEN PURGE_SYS->N_PAGES_HANDLED OVERFLOWS

Change the type of purge_sys_t::n_pages_handled and purge_sys_t::handle_limit
to ulonglong from ulint. On a 32 bit system doing ~700 deletes per second the
counters can overflow in ~3.5 months, if they are 32 bit.

Approved by Jimmy Yang over IM.

innobase/include/trx0purge.h

@@ -120,9 +120,9 @@ struct trx_purge_struct{
 	read_view_t*	view;		/* The purge will not remove undo logs
 					which are >= this view (purge view) */
 	mutex_t		mutex;		/* Mutex protecting the fields below */
-	ulint		n_pages_handled;/* Approximate number of undo log
+	ulonglong	n_pages_handled;/* Approximate number of undo log
 					pages processed in purge */
-	ulint		handle_limit;	/* Target of how many pages to get
+	ulonglong	handle_limit;	/* Target of how many pages to get
 					processed in the current purge */
 	/*------------------------------*/
 	/* The following two fields form the 'purge pointer' which advances

innobase/trx/trx0purge.c

@@ -1041,7 +1041,7 @@ trx_purge(void)
 {
 	que_thr_t*	thr;
 /*	que_thr_t*	thr2; */
-	ulint		old_pages_handled;
+	ulonglong	old_pages_handled;
 
 	mutex_enter(&(purge_sys->mutex));
 
@@ -1135,7 +1135,7 @@ trx_purge(void)
 		(ulong) purge_sys->n_pages_handled);
 	}
 
-	return(purge_sys->n_pages_handled - old_pages_handled);
+	return((ulint) (purge_sys->n_pages_handled - old_pages_handled));
 }
 
 /**********************************************************************