Index: http-transport.scm
==================================================================
--- http-transport.scm
+++ http-transport.scm
@@ -307,19 +307,23 @@
 (define (http-transport:server-dat-get-iface         vec)    (vector-ref  vec 0))
 (define (http-transport:server-dat-get-port          vec)    (vector-ref  vec 1))
 (define (http-transport:server-dat-get-api-uri       vec)    (vector-ref  vec 2))
 (define (http-transport:server-dat-get-api-url       vec)    (vector-ref  vec 3))
 (define (http-transport:server-dat-get-api-req       vec)    (vector-ref  vec 4))
+(define (http-transport:server-dat-get-last-access   vec)    (vector-ref  vec 5))
 
 (define (http-transport:server-dat-make-url vec)
   (if (and (http-transport:server-dat-get-iface vec)
 	   (http-transport:server-dat-get-port  vec))
       (conc "http://" 
 	    (http-transport:server-dat-get-iface vec)
 	    ":"
 	    (http-transport:server-dat-get-port  vec))
       #f))
+
+(define (http-transport:server-dat-update-last-access vec)
+  (vector-set! vec 5 (current-seconds)))
 
 ;;
 ;; connect
 ;;
 (define (http-transport:client-connect iface port)

Index: rmt.scm
==================================================================
--- rmt.scm
+++ rmt.scm
@@ -57,10 +57,20 @@
 
 ;; cmd is a symbol
 ;; vars is a json string encoding the parameters for the call
 ;;
 (define (rmt:send-receive cmd rid params)
+  ;; clean out old connections
+  (let ((expire-time (- (current-seconds) 60)))
+    (for-each 
+     (lambda (run-id)
+       (let ((connection (hash-table-ref *runremote* run-id)))
+	 (if (> (http-transport:server-dat-get-last-access connection) expire-time)
+	     (begin
+	       (debug:print-info 0 "Discarding connection to server for run-id " run-id ", too long between accesses")
+	       (hash-table-delete! *runremote* run-id)))))
+     (hash-table-keys *runremote*)))
   (let* ((run-id          (if rid rid 0))
 	 (connection-info (let ((cinfo (hash-table-ref/default *runremote* run-id #f)))
 			    (if cinfo
 				cinfo
 				;; NB// can cache the answer for server running for 10 seconds ...
@@ -72,10 +82,11 @@
 					  #f))
 				    #f))))
 	 (jparams         (db:obj->string params)))
     (if connection-info
 	(let ((res             (http-transport:client-api-send-receive run-id connection-info cmd jparams)))
+	  (http-transport:server-dat-update-last-access connection-info)
 	  (if res
 	      (db:string->obj res)
 	      (let ((new-connection-info (client:setup run-id)))
 		(debug:print 0 "WARNING: Communication failed, trying call to http-transport:client-api-send-receive again.")
 		(rmt:send-receive cmd run-id params))))