Index: dbfile.scm
==================================================================
--- dbfile.scm
+++ dbfile.scm
@@ -1010,10 +1010,11 @@
 	 (jfile     (conc fname"-journal"))
 	 #;(subdb     (if have-struct
 			(dbfile:get-subdb dbstruct run-id)
 			#f))
 	 ) ;; was 25
+    (assert (sqlite3:database? db) "FATAL: db:with-db, db is not a database, db="db", fname="fname)
     (if (file-exists? jfile)
 	(begin
 	  (dbfile:print-err "INFO: "jfile" exists, delaying to reduce database load")
 	  (thread-sleep! 0.2)))
     (if (and use-mutex

Index: http-transport.scm
==================================================================
--- http-transport.scm
+++ http-transport.scm
@@ -504,11 +504,23 @@
 	  (if (and no-sync-db
 		   (common:low-noise-print 10 "sync-all")) ;; cheesy way to reduce frequency of running sync :)
               (begin
 		(if (common:low-noise-print 120 "sync-all-print")
                     (debug:print 0 *default-log-port* "keep-running calling db:all-db-sync at " (time->string (seconds->local-time) "%H:%M:%S")))
-		(db:all-db-sync *dbstruct-dbs*))))
+		(db:all-db-sync *dbstruct-dbs*)
+		(if (common:low-noise-print 1800 "sync-back") ;; every half hour do a reverse sync
+		    (let* ((lockfile (conc *toppath*"/.megatest/syncback.lock"))
+			   (locked   (common:simple-file-lock lockfile)))
+		      (if locked
+			  (begin
+			    (db:multi-db-sync
+			     *dbstruct-dbs*
+			     'dejunk
+			     'adj-testids
+			     'old2new)
+			    (common:simple-file-release-lock lockfile)))))
+		)))
       
       ;; when things go wrong we don't want to be doing the various queries too often
       ;; so we strive to run this stuff only every four seconds or so.
       (let* ((sync-time (- (current-milliseconds) start-time))
 	    (rem-time  (quotient (- 4000 sync-time) 1000)))