Megatest

	  (set! *dbfile:num-handles-in-use* (+ *dbfile:num-handles-in-use* 1))
	  (stack-pop! (dbr:subdb-dbstack subdb))))))

;; return a previously opened db handle to the stack of available handles
(define (dbfile:add-dbdat dbstruct run-id dbdat)
  (let* ((subdb (dbfile:get-subdb dbstruct run-id))
	 (age   (- (current-seconds)(dbr:dbdat-birth-sec dbdat))))
    (if (> age 300) ;; just testing - discard and close after 30 sec
	(begin
	  ;; (map sqlite3:finalize! (hash-table-values (dbr:dbdat-stmt-cache dbdat)))
	  ;; (sqlite3:finalize! (dbr:dbdat-dbh dbdat))
	  (dbfile:print-err "INFO: Discarded dbdat over 30 sec old ("age"s)"))
	(begin
	  (set! *dbfile:num-handles-in-use* (- *dbfile:num-handles-in-use* 1))
	  (stack-push! (dbr:subdb-dbstack subdb) dbdat)))))

	  (dbfile:print-err "INFO: dbfile:cautious-open-database: journal file " busy-file " exists, trying again in few seconds.")
	  (thread-sleep! 1)
	  (if (eq? tries-left 2)
	      (begin
		(dbfile:print-err "INFO: forcing journal rollup "busy-file)
		(dbfile:brute-force-salvage-db fname)))
	  (dbfile:cautious-open-database fname init-proc (- tries-left 1)))

	(let* ((result (condition-case


			   (dbfile:with-simple-file-lock
			    (conc fname ".lock")
			    (lambda ()



			      (let* ((db-exists (file-exists? fname))
				     (db        (sqlite3:open-database fname)))
				(if (and init-proc (not db-exists))
				    (init-proc db))




				db)))
			 (exn (io-error)
			      (dbfile:print-err exn "ERROR: i/o error with " fname ". Check permissions, disk space etc. and try again.")
			      (retry))
			 (exn (corrupt)
			      (dbfile:print-err exn "ERROR: database " fname " is corrupt. Repair it to proceed.")
			      (retry))
			 (exn (busy)
			      (dbfile:print-err exn "ERROR: database " fname
						" is locked. Try copying to another location, remove original and copy back.")
			      (retry))
			 (exn (permission)(dbfile:print-err exn "ERROR: database " fname " has some permissions problem.")
			      (retry))
			 (exn ()
			      (dbfile:print-err exn "ERROR: Unknown error with database " fname " message: "
						((condition-property-accessor 'exn 'message) exn))
			      (retry)))))
          #;(if (file-write-access? fname)
	  (dbfile:simple-file-release-lock lock-file))
	  result))))

(define (dbfile:brute-force-salvage-db fname)
  (let* ((backupfname (conc fname"-"(current-process-id)".bak"))
	 (cmd (conc "cp "fname" "backupfname";mv "fname" "(conc fname ".delme;")
		    "cp "backupfname" "fname)))
    (dbfile:print-err "WARNING: attempting recovery of file "fname" by running commands:\n"

;; use (db:no-sync-del! db keyname) to release the lock
;;
(define (db:no-sync-get-lock db keyname)
  (sqlite3:with-transaction
   db
   (lambda ()
     (condition-case
	 (let* ((curr-val (db:no-sync-get/default db keyname #f)))
	   (if curr-val
	       `(#f . ,curr-val)   ;; (sqlite3:first-result db "SELECT val FROM no_sync_metadat WHERE var=?;" keyname))
	       (let ((lock-time (current-seconds)))
		 (sqlite3:execute db "INSERT OR REPLACE INTO no_sync_metadat (var,val) VALUES(?,?);" keyname lock-time)
		 `(#t . ,lock-time))))
       (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 . ,(current-seconds)))))))

(define (db:no-sync-get-lock-timeout db keyname timeout)
  (let* ((lockdat (db:no-sync-get-lock db keyname)))
    (match lockdat
      ((#f . lock-time)
       (if (> (- (current-seconds) (if (string? lock-time)(string->number lock-time)lock-time)) timeout)
	   (let ((lock-time (current-seconds)))
	     ;; (debug:print-info 2 *default-log-port* "db:no-sync-get-lock keyname=" keyname ", lock-time=" lock-time ", exn=" exn)
	     (sqlite3:execute db "INSERT OR REPLACE INTO no_sync_metadat (var,val) VALUES(?,?);" keyname lock-time)
	     `(#t . ,lock-time))
	   lockdat))
      (else lockdat))))

;; NOTE: This will steal the lock after timeout of waiting.
;;
(define (db:with-no-sync-lock db keyname timeout proc)
  (let* ((lockdat  (db:no-sync-get-lock-timeout db keyname))
	 (gotlock  (car lockdat))
	 (locktime (cdr lockdat)))
    (if gotlock
	(let ((res (proc)))
	  (db:no-sync-del! db keyname)
	  res))))
  
;;======================================================================
;; sync back functions pulled from db.scm
;;======================================================================

;; 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 keys dbinit)

(define (dbfile:simple-file-release-lock fname)
  (handle-exceptions
      exn
      #f ;; I don't really care why this failed (at least for now)
    (delete-file* fname)))

(define (dbfile:with-simple-file-lock fname proc #!key (expire-time 300))
  (let ((gotlock (dbfile:simple-file-lock-and-wait fname expire-time: expire-time)))
    (if gotlock
	(let ((res (proc)))
	  (dbfile:simple-file-release-lock fname)
	  res)
	(assert #t "FATAL: simple file lock never got a lock."))))
  
)