Megatest

      (args:get-arg "-use-db-cache") ;; feels like a bad idea ...
      ))

(define (common:legacy-sync-required)
  (configf:lookup *configdat* "setup" "megatest-db"))

;; run-ids
;;    if #f use *db-local-sync* : or 'local-sync-flags
;;    if #t use timestamps      : or 'timestamps
(define (common:sync-to-megatest.db run-ids) 
  (let ((start-time         (current-seconds))
        (run-ids-to-process (if (list? run-ids)
                                run-ids
                                (if (or (eq? run-ids 'timestamps)(eq? run-ids #t))
                                    (db:get-changed-run-ids (let* ((mtdb-fpath (conc *toppath* "/megatest.db"))
                                                                   (mtdb-exists (file-exists? mtdb-fpath)))
                                                              (if mtdb-exists
                                                                  (file-modification-time mtdb-fpath)
                                                                  0)))
                                    (hash-table-keys *db-local-sync*)))))
    (debug:print-info 4 *default-log-port* "Processing run-ids: " run-ids-to-process)

               (debug:print-info 3 *default-log-port* "Sync of newdb to olddb for run-id " run-id " completed in " sync-time " seconds")
               (if (common:low-noise-print 30 "sync new to old")
                   (debug:print-info 0 *default-log-port* "Sync of newdb to olddb for run-id " run-id " completed in " sync-time " seconds")))
             (hash-table-delete! *db-local-sync* run-id)))
       (mutex-unlock! *db-multi-sync-mutex*))
     run-ids-to-process)))

(define (common:watchdog)
  (thread-sleep! 0.05) ;; delay for startup
  (let ((legacy-sync (common:legacy-sync-required))
	(debug-mode  (debug:debug-mode 1))
	(last-time   (current-seconds)))
    (if (or (common:legacy-sync-recommended)
	    legacy-sync)
	(let loop ()
	  ;; sync for filesystem local db writes
	  ;;
	  (let ((start-time   (current-seconds)))
	    (common:sync-to-megatest.db 'local-sync-flags)
	    (if (and debug-mode
		     (> (- start-time last-time) 60))
		(begin
		  (set! last-time start-time)
		  (debug:print-info 4 *default-log-port* "timestamp -> " (seconds->time-string (current-seconds)) ", time since start -> " (seconds->hr-min-sec (- (current-seconds) *time-zero*))))))

	  ;; keep going unless time to exit
	  ;;
	  (if (not *time-to-exit*)
	      (let delay-loop ((count 0))
		(if (and (not *time-to-exit*)
			 (< count 4)) ;; was 11, changing to 4. 
		    (begin
		      (thread-sleep! 1)
		      (delay-loop (+ count 1))))
		(loop)))
	  (if (common:low-noise-print 30)
	      (debug:print-info 0 *default-log-port* "Exiting watchdog timer, *time-to-exit* = " *time-to-exit*))))))

(define (std-exit-procedure)
  (let ((no-hurry  (if *time-to-exit* ;; hurry up
		       #f
		       (begin
			 (set! *time-to-exit* #t)
			 #t))))

;; TODO: Move this inside (main)
;;
(if (not (launch:setup))
    (begin
      (print "Failed to find megatest.config, exiting") 
      (exit 1)))

;; create a watch dog to move changes from lt/.db/*.db to megatest.db
;;
(if (file-write-access? (conc *toppath* "/megatest.db"))
    (thread-start! (make-thread common:watchdog "Watchdog thread"))
    (if (not (args:get-arg "-use-db-cache"))
	(begin
	  (debug:print-info 0 *default-log-port* "Forcing db-cache mode due to read-only access to megatest.db")
	  (hash-table-set! args:arg-hash "-use-db-cache" #t))))

;; data common to all tabs goes here
;;
(defstruct dboard:commondat
  ((curr-tab-num 0) : number)
  please-update  
  tabdats

;;    if db already open - return inmem
;;    if db not open, open inmem, rundb and sync then return inmem
;;    inuse gets set automatically for rundb's
;;
(define (db:get-db dbstruct run-id) 
  (if (sqlite3:database? dbstruct) ;; pass sqlite3 databases on through
      dbstruct
      (if (pair? dbstruct)
	  dbstruct                 ;; pass pair ( db . path ) on through
	  (begin
	    ;; (assert (dbr:dbstruct? dbstruct)) ;; so much legacy, but by here we should have a genuine dbstruct
	(let ((dbdat (if (or (not run-id)
			     (eq? run-id 0))
			 (db:open-main dbstruct)
			 (db:open-rundb dbstruct run-id)
			 )))
	      dbdat)))))

;; legacy handling of structure for managing db's. Refactor this into dbr:?
(define (db:dbdat-get-db dbdat)
  (if (pair? dbdat)
      (car dbdat)
      dbdat))

(define (db:open-local-db-handle)
  (or *dbstruct-db*
      (let ((dbstruct (db:setup #f local: #t)))
	(set! *dbstruct-db* dbstruct)
	dbstruct)))
	  
;; Open the classic megatest.db file in toppath
;;
;;   NOTE: returns a dbdat not a dbstruct!
;;
(define (db:open-megatest-db #!key (path #f))
  (let* ((dbpath       (or path (conc *toppath* "/megatest.db")))
	 (dbexists     (file-exists? dbpath))
	 (db           (db:lock-create-open dbpath
					    (lambda (db)
					      (db:initialize-main-db db)

  (if (eq? access-mode 'cached)
      (apply db:call-with-cached-db db-cmd params)
      (apply rmt-cmd params)))

;; return the target db handle so it can be used
;;
(define (db:cache-for-read-only source target #!key (use-last-update #f))

  (if (and (hash-table-ref/default *global-db-store* target #f)
	   (>= (file-modification-time target)(file-modification-time source)))
      (hash-table-ref *global-db-store* target)
      (let* ((toppath   (launch:setup))
	     (targ-db-last-mod (if (file-exists? target)
				   (file-modification-time target)
				   0))

(define (db:call-with-cached-db proc . params)
  ;; first cache the db in /tmp
  (let* ((cname-part (conc "megatest_cache/" (common:get-testsuite-name)))
	 (fname      (conc  (common:get-area-path-signature) ".db"))
	 (cache-dir  (common:get-create-writeable-dir
		      (list (conc "/tmp/" (current-user-name) "/" cname-part)
			    (conc "/tmp/" (current-user-name) "-" cname-part)
			     (conc "/tmp/" (current-user-name) "_" cname-part))))
	 (megatest-db (conc *toppath* "/megatest.db")))
    ;; (debug:print-info 0 *default-log-port* "Using cache dir " cache-dir)
    (if (not cache-dir)
	(begin
	  (debug:print 0 *default-log-port* "ERROR: Failed to find an area to write the cache db")
	  (exit 1))
	(let* ((th1      (make-thread
			  (lambda ()
			    (if (and (file-exists? megatest-db)
				     (file-write-access? megatest-db))
				(begin
				  (common:sync-to-megatest.db 'timestamps) ;; internally mutexes on *db-local-sync*
				  (debug:print-info 2 *default-log-port* "Done syncing to megatest.db"))))
			  "call-with-cached-db sync-to-megatest.db"))
	       (cache-db (db:cache-for-read-only
			  megatest-db
			  (conc cache-dir "/" fname)
			  use-last-update: #t)))
	  (thread-start! th1)
	  (apply proc cache-db params)
	  ))))

;; options:
;;
;;  'killservers  - kills all servers
;;  'dejunk       - removes junk records

	 (resdat         (if (not (and read-only qry-is-write))
			     (api:execute-requests dbstruct-local (vector (symbol->string cmd) params))
			     (vector #t '())))
	 (success        (vector-ref resdat 0))
	 (res            (vector-ref resdat 1))
	 (duration       (- (current-milliseconds) start)))
    (if (and read-only qry-is-write)

        (debug:print 0 *default-log-port* "ERROR: attempt to write to read-only database ignored. cmd=" cmd))

    (if (not success)
	(if (> remretries 0)
	    (begin
	      (debug:print-error 0 *default-log-port* "local query failed. Trying again.")
	      (thread-sleep! (/ (random 5000) 1000)) ;; some random delay 
	      (rmt:open-qry-close-locally cmd run-id params remretries: (- remretries 1)))
	    (begin