Megatest

	 (dbdir         (conc areapath "/.mtdb")))
    (if (and (not *journal-stats*)
	     (file-exists? dbdir))
	(tt:start-stats dbdir)) ;; fixme - find the right call to get the db directory
    
    ;; check the load on dbfname and add some delay using a droop curve of sorts
    (if *journal-stats*
	(let* ((stats (tt:get-journal-stats))
	(let* ((load  (tt:get-journal-stats dbfname)))
	       (load  (or (alist-ref dbfname stats equal?) 0)))
	  (if (> load 0)
	      (let ((dely (* 10 load)))
		(debug:print 0 *default-log-port* "Journal load "load" delaying queries "dely"s.")
		(thread-sleep! dely)))))
	
    (case (rmt:transport-mode)
      ((tcp)

	 (all-tests-registry     (runs:dat-all-tests-registry runsdat))
	 (run-limits-info        (runs:dat-can-run-more-tests runsdat))
	 ;; (runs:can-run-more-tests run-id jobgroup max-concurrent-jobs)) ;; look at the test jobgroup and tot jobs running
	 (have-resources         (and (if *journal-stats*
					  (let* ((dbfname (conc
							   (dbfile:run-id->dbnum run-id)
							   ".db"))
						 (stats (tt:get-journal-stats))
						 (load (tt:get-journal-stats dbfname)))
						 (load  (or (alist-ref dbfname stats equal?) 0)))
					    (if (> load 0.1) ;; dbs too busy to start more tests
						(begin
						 (debug:print-info 0 *default-log-port* "Gating launch due to db load "load" based on journal file observations for "dbfname)
						 #f)
						#t))
					  #t) ;; if journal monitoring not started do not gate
				      (car run-limits-info)))

    (directory-fold
     (lambda (fname res)
       ;; is it a journal file?
       (let ((parts (string-match "^(.*\\.db)-journal.*" fname)))
	 (match parts
	   ((_ dbfname)
	    (hash-table-set! (jstats-jcount jstat) dbfname
			     (+ (hash-table-ref/default (jstats-jcount jstat) dbfname 0) 1)
			     (+ (hash-table-ref/default (jstats-jcount jstat) dbfname 0) 1.0)
			     ))
	   (else #f)
	   )))
     '()
     dbdir 
     )))

;; call this to start a thread that is keeping the journal-stats up to date.
(define (tt:start-stats dbdir)
  
  (thread-start!
   (make-thread
    (lambda ()(tt:journal-stats-run dbdir)) "Journal stats collection thread")))

(define (tt:get-journal-stats)
(define (tt:get-journal-stats #!optional (dbfname #f))
  (let* ((result    (make-jstats))
	 (hitcounts (jstats-jcount result)))
    (if *journal-stats*
	(begin
	  (mutex-lock! *journal-stats-mutex*)
	  (hash-table-for-each
	   *journal-stats*

		(lambda (dbfname hit-count)
		  (hash-table-set! hitcounts dbfname
				   (+ hit-count
				      (hash-table-ref/default hitcounts dbfname 0))))))))
	  (mutex-unlock! *journal-stats-mutex*))
	(debug:print 0 *default-log-port* "INFO: *journal-stats* not set."))
    ;; convert to normalized alist
    (let ((tot  (min (jstats-count result) 1)) ;; avoid divide by zero
	  (hits (jstats-jcount result))) ;; 1.db => count
      (hash-table-map
       hits
       (lambda (fname hitcount)
	 (cons fname (/ hitcount tot)))))))
    (let* ((tot  (min (jstats-count result) 1)) ;; avoid divide by zero
	   (hits (jstats-jcount result)) ;; 1.db => count
	   (res  (hash-table-map
		  hits
		  (lambda (fname hitcount)
		    (cons fname (/ hitcount tot))))))
      (if dbfname
	  (or (alist-ref dbfname res equal?) 0)
	  res))))

;; megatest> (import tcp-transportmod)
;; megatest> (tt:write-load-tracking ".mtdb")
;; megatest> (hash-table-keys *journal-stats*)
;; (172060297)
;; megatest> (jstats->alist (hash-table-ref *journal-stats* 172060297))
;; ((count . 1) (jcount . #<hash-table (1)>))
;; megatest> (jstats-jcount (hash-table-ref *journal-stats* 172060297))
;; #<hash-table (1)>
;; megatest> (hash-table->alist (jstats-jcount (hash-table-ref *journal-stats* 172060297)))
;; (("1.db" . 4))

)