Index: common.scm
==================================================================
--- common.scm
+++ common.scm
@@ -50,20 +50,22 @@
 (define *alt-log-file* #f)  ;; used by -log
 (define *common:denoise*    (make-hash-table)) ;; for low noise printing
 
 ;; DATABASE
 (define *dbstruct-db*  #f)
-(define *db-stats* (make-hash-table)) ;; hash of vectors < count duration-total >
+(define *db-stats*            (make-hash-table)) ;; hash of vectors < count duration-total >
 (define *db-stats-mutex*      (make-mutex))
 (define *db-sync-mutex*       (make-mutex))
 (define *db-multi-sync-mutex* (make-mutex))
 (define *db-local-sync*       (make-hash-table)) ;; used to record last touch of db
 (define *megatest-db*         #f)
 (define *last-db-access*      (current-seconds))  ;; update when db is accessed via server
 (define *db-write-access*     #t)
 (define *inmemdb*             #f)
 (define *task-db*             #f) ;; (vector db path-to-db)
+(define *db-access-allowed*   #t) ;; flag to allow access
+(define *db-access-mutex*     (make-mutex))
 
 ;; SERVER
 (define *my-client-signature* #f)
 (define *transport-type*    'http)
 (define *rpc:listener*      #f) ;; if set up for server communication this will hold the tcp port
@@ -112,14 +114,31 @@
   (set! *test-info*          (make-hash-table))
   (set! *run-info-cache*     (make-hash-table))
   (set! *env-vars-by-run-id* (make-hash-table))
   (set! *test-id-cache*      (make-hash-table)))
 
-;; Generic string database (normalization of sorts)
+;; Generic string database
 (define sdb:qry #f) ;; (make-sdb:qry)) ;;  'init #f)
-;; Generic path database (normalization of sorts)
+;; Generic path database
 (define *fdb* #f)
+
+;;======================================================================
+;; L O C K E R S   A N D   B L O C K E R S 
+;;======================================================================
+
+;; block further accesses to databases. Call this before shutting db down
+(define (common:db-block-further-queries)
+  (mutex-lock! *db-access-mutex*)
+  (set! *db-access-allowed* #f)
+  (mutex-unlock! *db-access-mutex*))
+
+(define (common:db-access-allowed?)
+  (let ((val (begin
+	       (mutex-lock! *db-access-mutex*)
+	       *db-access-allowed*
+	       (mutex-unlock! *db-access-mutex*))))
+    val))
 
 ;;======================================================================
 ;; U S E F U L   S T U F F
 ;;======================================================================
 

Index: db.scm
==================================================================
--- db.scm
+++ db.scm
@@ -278,10 +278,12 @@
 
 ;; close all opened run-id dbs
 (define (db:close-all dbstruct)
   ;; finalize main.db
   (db:sync-touched dbstruct 0 force-sync: #t)
+  (common:db-block-further-queries)
+  (mutex-lock! *db-sync-mutex*) ;; with this perhaps it isn't necessary to use the block-further-queries mechanism?
   (sqlite3:finalize! (db:get-db dbstruct #f))
   (let* ((local (dbr:dbstruct-get-local dbstruct))
 	 (rundb (dbr:dbstruct-get-rundb dbstruct)))
     (if local
 	(for-each
@@ -296,11 +298,12 @@
 	     (sqlite3:database? rundb))
 	(handle-exceptions
 	 exn
 	 #t ;; (debug:print 0 "WARNING: database files may not have been closed correctly. Consider running -cleanup-db")
 	 (sqlite3:interrupt! rundb)
-	 (sqlite3:finalize! rundb #t)))))
+	 (sqlite3:finalize! rundb #t))))
+  (mutex-unlock! *db-sync-mutex*))
 
 (define (db:open-inmem-db)
   (let* ((db      (sqlite3:open-database ":memory:"))
 	 (handler (make-busy-timeout 3600)))
     (db:initialize-run-id-db db)

Index: rmt.scm
==================================================================
--- rmt.scm
+++ rmt.scm
@@ -168,12 +168,14 @@
       ;; mark this run as dirty if this was a write
       (if (not (member cmd api:read-only-queries))
 	  (let ((start-time (current-seconds)))
 	    (mutex-lock! *db-multi-sync-mutex*)
 	    (let ((last-sync (hash-table-ref/default *db-local-sync* run-id 0)))
-	      (if (> (- start-time last-sync) 5) ;; every five seconds
+	      (if (and (> (- start-time last-sync) 5) ;; every five seconds
+		       (common:db-access-allowed?))
 		  (begin
+		    ;; MOVE THIS TO A THREAD?
 		    (db:multi-db-sync (list run-id) 'new2old)
 		    (debug:print-info 0 "Sync of newdb to olddb for run-id " run-id " completed in " (- (current-seconds) start-time) " seconds")
 		    (hash-table-set! *db-local-sync* run-id start-time))))
 	    (mutex-unlock! *db-multi-sync-mutex*)))
       res)))