Index: dbmod.scm
==================================================================
--- dbmod.scm
+++ dbmod.scm
@@ -149,10 +149,12 @@
 	    (handler (sqlite3:make-busy-timeout 136000)))
        (sqlite3:set-busy-handler! db handler)
        (if write-access
 	   (init-proc db))
        db))))
+
+(define *sync-in-progress* #f)
 
 ;; Open the inmem db and the on-disk db
 ;; populate the inmem db with data
 ;;
 ;; Updates fields in dbstruct
@@ -194,13 +196,18 @@
     (dbr:dbstruct-ondiskdb-set!  dbstruct db)
     (dbr:dbstruct-dbfile-set!    dbstruct dbfullname)
     (dbr:dbstruct-dbfname-set!   dbstruct dbfname)
     (dbr:dbstruct-sync-proc-set! dbstruct
 				 (lambda (last-update)
-				   ;; (if db
-				       (dbmod:sync-gasket tables last-update inmem db
-						    dbfullname syncdir))) ;; )
+				   (if *sync-in-progress*
+				       (debug:print 0 *default-log-port* "WARNING: overlapping calls to sync to disk")
+				       (begin
+					 (set! *sync-in-progress* #t)
+					 (dbmod:sync-gasket tables last-update inmem db
+							    dbfullname syncdir)
+					 (thread-sleep! 0.5) ;; ensure at least 1/2 second down time between sync calls
+					 (set! *sync-in-progress* #f)))))
     ;; (dbmod:sync-tables tables #f db inmem)
     ;; (if db
     (dbmod:sync-gasket tables #f inmem db dbfullname 'fromdest) ;; ) ;; load into inmem
     (dbr:dbstruct-last-update-set! dbstruct (current-seconds)) ;; should this be offset back in time by one second?
     dbstruct))
@@ -225,11 +232,10 @@
        ((todisk)
 	(dbmod:sync-tables tables last-update inmem dbh)
 	)
        (else
 	(dbmod:sync-tables tables last-update dbh inmem))))))
-
 
 (define (dbmod:close-db dbstruct)
   ;; do final sync to disk file
   ;; (do-sync ...)
   (sqlite3:finalize! (dbr:dbstruct-ondiskdb dbstruct)))