Megatest

	 (write-access (file-write-access? dbpath)))
    (debug:print-info 13 *default-log-port* "db:open-megatest-db "dbpath)
    (if (and dbexists (not write-access))
	(set! *db-write-access* #f))
    ;; (cons db dbpath)))
    (make-dbr:dbdat dbfile: dbpath dbh: db read-only: (not write-access))))

;; sync run from tmp disk to nfs disk if touched
;;
(define (db:sync-touched dbstruct run-id #!key (force-sync #f))
  (debug:print-info 0 *default-log-port* "db:sync-touched Syncing: " (conc (if run-id run-id "main") ".db"))

  (let* (
	 (subdb   (or (dbfile:get-subdb dbstruct run-id) (dbfile:init-subdb dbstruct run-id db:initialize-main-db)))
         (tmpdbfile (dbr:subdb-tmpdbfile subdb))
	 (mtdb    (dbr:subdb-mtdbdat subdb))
         (tmpdb (dbfile:open-sqlite3-db tmpdbfile #f))


	 (start-t (current-seconds)))

    (mutex-lock! *db-multi-sync-mutex*)
    (let ((update_info (cons "last_update" (if force-sync 0 *db-last-sync*) )))
      (mutex-unlock! *db-multi-sync-mutex*)
      (db:sync-tables (db:sync-all-tables-list dbstruct) update_info tmpdb mtdb))
    (mutex-lock! *db-multi-sync-mutex*)
    (set! *db-last-sync* start-t)
    (set! *db-last-access* start-t)

(define (db:sync-tables tbls last-update fromdb todb . slave-dbs)
  (handle-exceptions
   exn
   (begin
     (debug:print 0 *default-log-port* "EXCEPTION: database probably overloaded or unreadable in db:sync-tables.")
     (print-call-chain (current-error-port))
     (debug:print 0 *default-log-port* " message: " ((condition-property-accessor 'exn 'message) exn))
     (debug:print 0 *default-log-port* "exn=" (condition->list exn))
     (debug:print 0 *default-log-port* " status:  " ((condition-property-accessor 'sqlite3 'status) exn))
     (debug:print 0 *default-log-port* " src db:  " (dbr:dbdat-dbfile fromdb))
     (for-each (lambda (dbdat)
		 (let ((dbpath (dbr:dbdat-dbfile dbdat)))
		   (debug:print 0 *default-log-port* " dbpath:  " dbpath)
		   (if (not (db:repair-db dbdat))
		       (begin
			 (debug:print-error 0 *default-log-port* "Failed to rebuild " dbpath ", exiting now.")
			 (exit)))))
	       (cons todb slave-dbs))
     
     0)

   ;; this is the work to be done")
   (cond
    ((not fromdb) (debug:print 0 *default-log-port* "WARNING: db:sync-tables called with fromdb missing")
     -1)
    ((not todb)   (debug:print 0 *default-log-port* "WARNING: db:sync-tables called with todb missing")
     -2)
    ((not (sqlite3:database? (dbr:dbdat-dbh fromdb)))
     (debug:print-error 0 *default-log-port* "db:sync-tables called with fromdb not a database " fromdb)
   -3)
    ((not (sqlite3:database? (dbr:dbdat-dbh todb)))
     (debug:print-error 0 *default-log-port* "db:sync-tables called with todb not a database " todb)
   -4)

	    ;; set up the field->num table
	    (for-each
	     (lambda (field)
	       (hash-table-set! field->num field count)
	       (set! count (+ count 1)))
	     fields)



	    ;; read the source table
            ;; store a list of all rows in the table in fromdat, up to batch-len.
            ;; Then add fromdat to the fromdats list, clear fromdat and repeat.
	    (sqlite3:for-each-row
	     (lambda (a . b)
	       (set! fromdat (cons (apply vector a b) fromdat))
	       (if (> (length fromdat) batch-len)

                 (set! totrecords (+ totrecords 1)))

	    ;; tack on remaining records in fromdat
	    (if (not (null? fromdat))
		(set! fromdats (cons fromdat fromdats)))

	    (if (common:low-noise-print 120 "sync-records")
		(debug:print 0 *default-log-port* "found " totrecords " records to sync"))

	    (sqlite3:for-each-row
	     (lambda (a . b)
	       (hash-table-set! todat a (apply vector a b)))
	     (dbr:dbdat-dbh todb)
	     full-sel)

                                )
                            )
                            ))
			fromdat-lst))))
		  fromdats)


                 (if (> changed-rows 0)
	           (debug:print 0 *default-log-port* "table " tablename " changed rows: " changed-rows)
                 )


		 (sqlite3:finalize! stmth)
                 (if (member "last_update" field-names)
                    (db:create-trigger db tablename))))
	     (append (list todb) slave-dbs)
           )
          )
        )
	tbls)
       (let* ((runtime      (- (current-milliseconds) start-time))
	      (should-print (or (debug:debug-mode 12)
				(common:low-noise-print 120 "db sync" (> runtime 500))))) ;; low and high sync times treated as separate.
	 (if should-print (debug:print 0 *default-log-port* "INFO: db sync, total run time " runtime " ms"))
	 (for-each 
	  (lambda (dat)
	    (let ((tblname (car dat))
		  (count   (cdr dat)))
	      (set! tot-count (+ tot-count count))
	      (if (> count 0)
		  (if should-print (debug:print 0 *default-log-port* (format #f "    ~10a ~5a" tblname count))))))

;; 	  ))))




;; Get a lock from the no-sync-db for the from-db, then delta sync the from-db to the to-db, otherwise return #f

(define (db:lock-and-delta-sync no-sync-db dbstruct from-db-file runid)
  (assert (not *db-sync-in-progress*) "FATAL: db:lock-and-sync called while a sync is in progress.")
  (debug:print-info 3 *default-log-port* "db:lock-and-delta-sync")
  (let* ((lockdat  (db:no-sync-get-lock no-sync-db from-db-file))
	 (gotlock  (car lockdat))
	 (locktime (cdr lockdat)))

    (debug:print-info 3 *default-log-port* "db:lock-and-delta-sync: go lock?")
    (if gotlock
	(begin
          (debug:print 0 *default-log-port* "db:lock-and-delta-sync copying db")

          (db:sync-touched dbstruct runid)
	  (db:no-sync-del! no-sync-db from-db-file)
	  #t)
        (begin
          (debug:print 0 *default-log-port* "could not get lock for " from-db-file " from no-sync-db")
	  #f
        ))))




(define (db:all-db-sync dbstruct)
  (db:open-db dbstruct #f)
  (let* ((data-synced 0) ;; count of changed records
    (tmp-area       (common:get-db-tmp-area))
    (dbfiles        (glob (conc tmp-area"/.db/*.db")))
    (sync-durations (make-hash-table))
    (no-sync-db        (db:open-no-sync-db))
    )
    (for-each
     (lambda (file)
       (debug:print-info 3 *default-log-port* "file: " file)
       (let* ((fname (conc (pathname-file file) ".db"))
	      (fulln (conc *toppath*"/.db/"fname))
	      (time1 (if (file-exists? file)
			 (file-modification-time file)
			 (begin
			   (debug:print-info 0 *default-log-port* "Sync - I do not see file "file)
			   1)))
	      (time2 (if (file-exists? fulln)
			 (file-modification-time fulln)
			 (begin
			   (debug:print-info 0 *default-log-port* "Sync - I do not see file "fulln)
			   0)))
	      (changed (> time1 time2))
	      (do-cp (cond
		      ((not (file-exists? fulln)) ;; shouldn't happen, but this might recover
		       (debug:print-info 0 *default-log-port* "File "fulln" not found! Copying "fname" to "fulln)
		       #t)
		      (changed ;; (and changed
		       ;; (> (- (current-seconds) time1) 3)) ;; if file is changed and three seconds have passed.
		       #t)
		      ((and changed *time-to-exit*) ;; last sync
		       #t)
		      (else
		       #f))))
	 (if do-cp
	     (let* ((start-time (current-milliseconds))
              (fname (pathname-file file))
              (runid (if (string= fname "main") #f (string->number fname)))
              )
	       (debug:print-info 3 *default-log-port* "db:all-db-sync: fname: " fname", delta: " (- time1 time2) " seconds")

	       (db:lock-and-delta-sync no-sync-db dbstruct fname runid)
	       (hash-table-set! sync-durations (conc fname".db") (- (current-milliseconds) start-time)))
	     (debug:print-info 3 *default-log-port* "skipping sync. " file " is up to date")
         )
       )
     )
     dbfiles
    )
  )
   #t
)






;; options:
;;
;;  'killservers  - kills all servers
;;  'dejunk       - removes junk records
;;  'adj-testids  - move test-ids into correct ranges
;;  'old2new      - sync megatest.db to /tmp/.../megatest.db and /tmp/.../megatest_ref.db
;;  'new2old      - sync /tmp/.../megatest.db to megatest.db and /tmp/.../megatest_ref.db (and update data_synced)
;;  'closeall     - close all opened dbs
;;  'schema       - attempt to apply schema changes
;;  run-ids: '(1 2 3 ...) or #f (for all)
;;
(define (db:multi-db-sync dbstruct . options)

  (db:open-db dbstruct #f)

  (let* ((data-synced 0) ;; count of changed records
    (tmp-area       (common:get-db-tmp-area))
    (dbfiles        (glob (conc tmp-area"/.db/*.db")))
    (sync-durations (make-hash-table))
    )

                  (exit 1)))
                ;;(debug:print 1 *default-log-port* "INFO: ["(common:human-time)"] Syncer started (method="syncer")")
                )))
	    (debug:print-info 13 *default-log-port* "watchdog done."))
	  (debug:print-info 13 *default-log-port* "no need for watchdog on non-homehost"))))


(define (db:do-sync no-sync-db)
  (let* ((syncer (or (configf:lookup *configdat* "server" "sync-method") "delta-sync"))
    (dbstruct (db:setup #t)))

    (debug:print 0 *default-log-port* "db:do-sync: sync-method: " syncer)
    (cond
      ((equal? syncer "brute-force-sync")
       (db:run-lock-and-sync no-sync-db))
      ((equal? syncer "delta-sync")
       (debug:print 0 *default-log-port* "db:do-sync: db:multi-db-sync" )
       (let* (
	   (tmpdbpth (dbr:dbstruct-tmppath dbstruct))
	   (lockfile (conc tmpdbpth ".lock"))
	   (locked   (common:simple-file-lock lockfile)) 
	   (res      (if locked
                         ;; sync all dbs for this area
                



			 (db:all-db-sync dbstruct) 
                         #f
                     )
            )
           )
           (if res
	     (begin
	       (common:simple-file-release-lock lockfile)
	       (print "db:do-sync: Synced " res " records to megatest.db")
             )
	     (print "db:do-sync: Skipping sync, there is a sync in progress.")
           )