Megatest

		(begin
		  (dbr:dbstruct-localdb-set! dbstruct run-id db) ;; (dbr:dbstruct-inmem-set! dbstruct db) ;; direct access ...
		  db)
		(begin
		  (dbr:dbstruct-inmem-set!  dbstruct inmem)
		  ;; dec 14, 2014 - keep deleted records available. hunch is that they are needed for id placeholders
		  ;; (sqlite3:execute db "DELETE FROM tests WHERE state='DELETED';") ;; they just slow us down in this context
		  (db:sync-tables db:sync-tests-only #f db inmem)
		  (db:delay-if-busy refdb) ;; dbpath: (db:dbdat-get-path refdb)) ;; What does delaying here achieve? 
		  (dbr:dbstruct-refdb-set!  dbstruct refdb)
		  (db:sync-tables db:sync-tests-only #f inmem refdb) ;; use inmem as the reference, don't read again from db
		  ;; sync once more to deal with delays?
		  ;; (db:sync-tables db:sync-tests-only db inmem)
		  ;; (db:sync-tables db:sync-tests-only inmem refdb)
		  inmem)))))))

;; This routine creates the db if not already present. It is only called if the db is not already ls opened
;;

	    (if (or (not (number? mtime))
		    (not (number? stime))
		    (> mtime stime)
		    force-sync)
		(begin
		  (db:delay-if-busy maindb)
		  (db:delay-if-busy olddb)
		  (let ((num-synced (db:sync-tables (db:sync-main-list maindb) #f maindb olddb)))
		    (dbr:dbstruct-stime-set! dbstruct (current-milliseconds))
		    num-synced)
		  0))
	    (begin
	      ;; this can occur when using local access (i.e. not in a server)
	      ;; need a flag to turn it off.
	      ;;
	      (debug:print 3 *default-log-port* "WARNING: call to sync main.db to megatest.db but main not initialized")
	      0))
	;; any other runid is a run
	(if (or (not (number? mtime))
		(not (number? stime))
		(> mtime stime)
		force-sync)
	    (begin
	      (db:delay-if-busy rundb)
	      (db:delay-if-busy olddb)
	      (dbr:dbstruct-stime-set! dbstruct (current-milliseconds))
	      (let ((num-synced (db:sync-tables db:sync-tests-only #f inmem refdb rundb olddb)))
		;; (mutex-unlock! *http-mutex*)
		num-synced)
	      (begin
		;; (mutex-unlock! *http-mutex*)
		0))))))

(define (db:close-main dbstruct)

	 
	 (finalize! db)
	 #t))))))
    
;; tbls is ( ("tablename" ( "field1" [#f|proc1] ) ( "field2" [#f|proc2] ) .... ) )
;; db's are dbdat's
;;
;; if last-update specified ("field-name" . time-in-seconds)
;;    then sync only records where field-name >= time-in-seconds
;;    IFF field-name exists
;;
(define (db:sync-tables tbls last-update fromdb todb . slave-dbs)
  (mutex-lock! *db-sync-mutex*)
  (handle-exceptions
   exn
   (begin
     (mutex-unlock! *db-sync-mutex*)
     (debug:print 0 *default-log-port* "EXCEPTION: database probably overloaded or unreadable in db:sync-tables.")
     (print-call-chain (current-error-port))

	   (numrecs     (make-hash-table))
	   (start-time  (current-milliseconds))
	   (tot-count   0))
       (for-each ;; table
	(lambda (tabledat)
	  (let* ((tablename  (car tabledat))
		 (fields     (cdr tabledat))
		 (use-last-update  (if last-update
				       (if (pair? last-update)
					   (member (car last-update)    ;; last-update field name
						   (map car fields))
					   (begin
					     (debug:print 0 *default-log-port* "ERROR: parameter last-update for db:sync-tables must be a pair, received: " last-update) ;; found in fields
					     #f))
				       #f))
		 (num-fields (length fields))
		 (field->num (make-hash-table))
		 (num->field (apply vector (map car fields)))
		 (full-sel   (conc "SELECT " (string-intersperse (map car fields) ",") 
				   " FROM " tablename (if use-last-update ;; apply last-update criteria
							  (conc " " (car last-update) ">=" (cdr last-update))
							  "")
				   ";"))
		 (full-ins   (conc "INSERT OR REPLACE INTO " tablename " ( " (string-intersperse (map car fields) ",") " ) "
				   " VALUES ( " (string-intersperse (make-list num-fields "?") ",") " );"))
		 (fromdat    '())
		 (fromdats   '())
		 (totrecords 0)
		 (batch-len  (string->number (or (configf:lookup *configdat* "sync" "batchsize") "10")))
		 (todat      (make-hash-table))

			fromdat-lst))
		  ))
		  fromdats)
		 (sqlite3:finalize! stmth)))
	     (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 3 *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)

  (sqlite3:execute maindb "CREATE TRIGGER  IF NOT EXISTS update_run_stats_trigger AFTER UPDATE ON run_stats
                             FOR EACH ROW
                               BEGIN 
                                 UPDATE run_stats SET last_update=(strftime('%s','now'))
                                   WHERE id=old.id;
                               END;"))

(define *global-db-store* (make-hash-table))

;; 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))
	     (cache-db  (or (hash-table-ref/default *global-db-store* target #f)
			    (db:open-megatest-db path: target)))
	     (source-db (db:open-megatest-db path: source))
	     (curr-time (current-seconds))
	     (res      '())



	     (last-update (if use-last-update (cons "last_update" targ-db-last-mod) #f)))
	(db:sync-tables (db:sync-main-list source-db) last-update source-db cache-db)
	(db:sync-tables db:sync-tests-only last-update source-db cache-db)
	(hash-table-set! *global-db-store* target cache-db)
	cache-db)))






;; call a proc with a cached db
;;
(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)))))
    ;; (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* ((cache-db (db:cache-for-read-only
			  (conc *toppath* "/megatest.db")
			  (conc cache-dir "/" fname)
			  use-last-update: #t)))
	  (apply proc cache-db params)
	  ))))

;; options:
;;
;;  'killservers  - kills all servers
;;  'dejunk       - removes junk records
;;  'adj-testids  - move test-ids into correct ranges
;;  'old2new      - sync megatest.db records to .db/{main,1,2 ...}.db

	  (db:delay-if-busy mtdb)
	  (db:prep-megatest.db-for-migration mtdb)))

    ;; sync runs, test_meta etc.
    ;;
    (if (member 'old2new options)
	(begin
	  (db:sync-tables (db:sync-main-list mtdb) #f mtdb (db:get-db dbstruct #f))
	  (for-each 
	   (lambda (run-id)
	     (db:delay-if-busy mtdb)
	     (let ((testrecs (db:get-all-tests-info-by-run-id mtdb run-id))
		   (dbstruct (if toppath (make-dbr:dbstruct path: toppath local: #t) #f)))
	       (debug:print 0 *default-log-port* "INFO: Propagating " (length testrecs) " records for run-id=" run-id " to run specific db")
	       (db:replace-test-records dbstruct run-id testrecs)

                 (thread-start! 
                  (make-thread
                   (lambda ()
                     (let* ((fromdb (if toppath (make-dbr:dbstruct path: toppath local: #t) #f))
                            (frundb (db:dbdat-get-db (db:get-db fromdb run-id))))
                       (if (eq? run-id 0)
                           (let ((maindb  (db:dbdat-get-db (db:get-db fromdb #f))))
                             (db:sync-tables (db:sync-main-list dbstruct) #f (db:get-db fromdb #f) mtdb)
                             (set! dead-runs (db:clean-up-maindb (db:get-db fromdb #f))))
                           (begin
                             ;; NB// must sync first to ensure deleted tests get marked as such in megatest.db
                             (db:sync-tables db:sync-tests-only #f (db:get-db fromdb run-id) mtdb)
                             (db:clean-up-rundb (db:get-db fromdb run-id)))))
                     (set! count (+ count 1))
                     (debug:print 0 *default-log-port* "Finished clean up of "
                                  (if (eq? run-id 0)
                                      " main.db " (conc run-id ".db")) ", " count " of " total)))))
               all-run-ids))))