Megatest

  (sqlite3:with-transaction
   db
   (lambda ()
     (condition-case
      (let* ((curr-val (db:no-sync-get/default db keyname #f)))
	(if curr-val
	    (match (db:extract-time-identifier curr-val) ;; result->timestamp, identifier
	       ((timestamp ident)
		(if (equal? ident identifier)
	       ((timestamp . ident)
		(cons (equal? ident identifier) timestamp))
		    (cons #t timestamp)    ;; this *is* my lock
		    (cons #f timestamp)))  ;; nope, not my lock
	       (else (cons #f #f)))  ;; nope, not my lock
	       (else (cons #f 'malformed-lock)))  ;; lock malformed
	    (let ((curr-sec (current-seconds))
		  (lock-value (if identifier
				  (conc (current-seconds)"+"identifier)
				  (current-seconds))))
	      (sqlite3:execute db "INSERT OR REPLACE INTO no_sync_metadat (var,val) VALUES(?,?);" keyname lock-value)
	      (cons #t curr-sec))))
      (exn (io-error)  (dbfile:print-err "ERROR: i/o error with no-sync db. Check permissions, disk space etc. and try again."))
      (exn (corrupt)   (dbfile:print-err "ERROR: database no-sync db is corrupt. Repair it to proceed."))
      (exn (busy)      (dbfile:print-err "ERROR: database no-sync db is locked. Try copying to another location, remove original and copy back."))
      (exn (permission)(dbfile:print-err "ERROR: database no-sync db has some permissions problem."))
      (exn () ;; (status done) ;; I don't know how to detect status done but no data!
	   (dbfile:print-err "ERROR: Unknown error with database no-sync db message: exn="(condition->list exn)", \n"
			     ((condition-property-accessor 'exn 'message) exn))
	   #f)))))
	   (cons #f #f))))))

(define (db:no-sync-check-lock db keyname identifier)
  (let* ((curr-val (db:no-sync-get/default db keyname #f)))
    (match (db:extract-time-identifier curr-val) ;; result->timestamp, identifier
      ((timestamp . ident)
       (cons (equal? ident identifier) ident))
      (else  (cons #f 'no-lock)))))

;; get the lock, wait 0.25 seconds and verify still have it.
;; this should not be necessary given the use of transaction in
;; db:no-sync-get-lock-with-id but it does seem to be needed
;;
(define (db:no-sync-lock-and-check db keyname identifier)
  (let* ((result  (db:no-sync-get-lock-with-id db keyname identifier))
	 (gotlock (car result)))
    (if gotlock
	(begin
	  (thread-sleep! 0.25)
	  (db:no-sync-check-lock db keyname identifier))
	result)))
    
;; transaction protected lock aquisition
;; either:
;;    fails    returns  (#f . lock-creation-time)
;;    succeeds (returns (#t . lock-creation-time)
;; use (db:no-sync-del! db keyname) to release the lock
;;
(define (db:no-sync-get-lock db keyname)

      (let* ((servers (tt:get-server-info-sorted ttdat dbfname))
	     (ok      (cond
		       ((null? servers) #f) ;; not ok
		       ((equal? (list-ref (car servers) 6) ;; compare the servinfofile
				(tt-servinf-file ttdat))
			(let* ((res (if db-locked-in
					#t
					(let* ((lock-result
					(let* ((lock-result  ;; this is the primary lock - need to double verify that got it
						(dbfile:with-no-sync-db
						 nosyncdbpath
						 (lambda (db)
						   (db:no-sync-get-lock-with-id db dbfname
										;; (tt-servinf-file ttdat)
										(dbr:dbstruct-dbtmpname dbstruct)
										))))
						   (db:no-sync-lock-and-check db dbfname
									      (tt-servinf-file ttdat)
									      ;; (dbr:dbstruct-dbtmpname dbstruct)
									      ))))
					       (success (car lock-result)))
					  (if success
					      (begin
						(tt-state-set! ttdat 'running)
						(debug:print 0 *default-log-port* "Got server lock for "
						(debug:print 0 *default-log-port* "Got server lock for " dbfname)
							     dbfname)
						(set! db-locked-in #t)
						#t)
					      (begin
						(debug:print 0 *default-log-port* "Failed to get server lock for "dbfname)
						#f))))))
			  (if (and res (common:low-noise-print 120 "top server message"))
			      (debug:print-info 0 *default-log-port* "Keep running, I'm the top server for "