Megatest

			    ((ping) *server-signature*)
			    (else
			     (api:dispatch-request dbstruct cmd run-id params))))))
      (set! *api-process-request-count* newcount)
      (set! *db-last-access* (current-seconds))
      (match indat
	((cmd run-id params meta)
	 (let* ((db-ok  (let* ((dbfname (dbmod:run-id->dbfname run-id))
			       (ok      (equal? dbfname (dbr:dbstruct-dbfname dbstruct))))
			  (case cmd
			    ((ping) #t) ;; we are fine
			    (else
			     (if (not ok)(debug:print 0 *default-log-port* "ERROR: "cmd", run-id "run-id", not correct for dbfname "(dbr:dbstruct-dbfname dbstruct)))
			     (assert ok "FATAL: database file and run-id not aligned.")))))
	 (let* ((ttdat   *server-info*)
		(ttdat   *server-info*)
		(server-state (tt-state ttdat))
		(status  (cond
			  ;; ((> newcount 600) 'busy)
			  ;; ((> newcount 300) 'loaded)
			  ((> newcount 300) 'loaded)
			  (else 'ok)))
		(errmsg  (case status
			   ((busy)   (conc "Server overloaded, "newcount" threads in flight"))
			   ((loaded) (conc "Server loaded, "newcount" threads in flight"))
			   (else     #f)))
		(result  (case status
			   ((busy)  (- newcount 29)) ;; call back in as many seconds
			   ((loaded)
			    (if (eq? (rmt:transport-mode) 'tcp)
				(thread-sleep! 0.5))
			    (normal-proc cmd run-id params))
			   (else
			    (normal-proc cmd run-id params))))
		(meta   (case cmd
			  ((ping) `((sstate . ,server-state)))
			  (else   `((wait . ,delay-wait)))))
		(payload (list status errmsg result meta)))
	   (set! *api-process-request-count* (- *api-process-request-count* 1))
	   (serialize payload)))
	(else
	 (assert #f "FATAL: failed to deserialize indat "indat))))))
       

(define (api:dispatch-request dbstruct cmd run-id params)
  (if (and (not *no-sync-db*)
  (if (not *no-sync-db*)
	   (member cmd '(db:no-sync-set db:no-sync-get/default db:no-sync-del! db:no-sync-get-lock )))
      (db:open-no-sync-db))
  (case cmd
    ;;===============================================
    ;; READ/WRITE QUERIES
    ;;===============================================

    ((get-keys-write)                        (db:get-keys dbstruct)) ;; force a dummy "write" query to force server; for debug in -repl

;; (define *db-last-sync*        0)                 ;; last time the sync to megatest.db happened
(define *db-sync-in-progress* #f)                ;; if there is a sync in progress do not try to start another
;; (define *db-multi-sync-mutex* (make-mutex))      ;; protect access to *db-sync-in-progress*, *db-last-sync*
;; task db
(define *task-db*             #f) ;; (vector db path-to-db)
(define *db-access-allowed*   #t) ;; flag to allow access
;; (define *db-access-mutex*     (make-mutex)) ;; moved to dbfile
(define *db-transaction-mutex* (make-mutex))
;; (define *db-transaction-mutex* (make-mutex))
(define *db-cache-path*       #f)
;; (define *db-with-db-mutex*    (make-mutex))
(define *db-api-call-time*    (make-hash-table)) ;; hash of command => (list of times)

;; SERVER
(define *my-client-signature* #f)
(define *transport-type*    'http)             ;; override with [server] transport http|rpc|nmsg

  (read-only #f)
  (subdbs (make-hash-table))
  ;;
  ;; for the inmem approach (see dbmod.scm)
  ;; this is one db per server
  (inmem     #f)  ;; handle for the in memory copy
  (dbfile    #f)  ;; path to the db file on disk
  (dbfname   #f)  ;; short name of db file on disk (used to validate accessing correct db)
  (ondiskdb  #f)  ;; handle for the on-disk file
  (dbdat     #f)  ;; create a dbdat for the downstream calls such as db:with-db
  (last-update 0)
  (sync-proc #f)
  )

;; NOTE: Need one dbr:subdb per main.db, 1.db ...

(define *db-with-db-mutex*    (make-mutex))
(define *max-api-process-requests* 0)
(define *api-process-request-count* 0)
(define *db-write-access*     #t)
(define *db-last-sync*        0)                 ;; last time the sync to megatest.db happened
(define *db-multi-sync-mutex* (make-mutex))      ;; protect access to *db-sync-in-progress*, *db-last-sync*
(define *db-last-access*      (current-seconds))

(define *db-transaction-mutex* (make-mutex))

(define (db:generic-error-printout exn . message)
  (print-call-chain (current-error-port))
  (apply dbfile:print-err message)
  (dbfile:print-err
    ", error: "     ((condition-property-accessor 'exn 'message)   exn)
    ", arguments: " ((condition-property-accessor 'exn 'arguments) exn)

(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."))))
  

(define *get-cache-stmth-mutex* (make-mutex))

(define (db:get-cache-stmth dbdat db stmt)
  (mutex-lock! *get-cache-stmth-mutex*)
  (let* (;; (dbdat       (dbfile:get-dbdat dbstruct run-id))
	 (stmt-cache  (dbr:dbdat-stmt-cache dbdat))
	 ;; (stmth       (db:hoh-get stmt-cache db stmt))
	 (stmth       (hash-table-ref/default stmt-cache stmt #f)))
    (or stmth
	(let* ((newstmth (sqlite3:prepare db stmt)))
	  ;; (db:hoh-set! stmt-cache db stmt newstmth)
	  (hash-table-set! stmt-cache stmt newstmth)
	  newstmth))))


	 (stmth       (hash-table-ref/default stmt-cache stmt #f))
	 (result      (or stmth
			  (let* ((newstmth (sqlite3:prepare db stmt)))
			    ;; (db:hoh-set! stmt-cache db stmt newstmth)
			    (hash-table-set! stmt-cache stmt newstmth)
			    newstmth))))
    (mutex-unlock! *get-cache-stmth-mutex*)
    result))

)

;;======================================================================
;; Copyright 2017, Matthew Welland.
;; 
;; This file is part of Megatest.
;; 
;;     Megatest is free software: you can redistribute it and/or modify
;;     it under the terms of the GNU General Public License as published by

;;======================================================================
;; The inmem one-db file per server method goes in here
;;======================================================================

(define (dbmod:with-db dbstruct run-id r/w proc params)
  (let* ((dbdat  (dbmod:open-db dbstruct run-id (dbfile:db-init-proc)))
	 (dbh    (dbr:dbdat-dbh dbdat))
	 (dbh    (dbr:dbdat-dbh dbdat)) ;; this will be the inmem handle
	 (dbfile (dbr:dbdat-dbfile dbdat)))
    (apply proc dbdat dbh params)))

(define (dbmod:open-inmem-db initproc)
  (let* ((db      (sqlite3:open-database ":memory:"))
	 (handler (sqlite3:make-busy-timeout 3600)))
    (sqlite3:set-busy-handler! db handler)

			  (lambda ()
			    (let* ((db      (sqlite3:open-database dbfullname))
				   (handler (sqlite3:make-busy-timeout 136000)))
			      (sqlite3:set-busy-handler! db handler)
			      (if write-access
				  (init-proc db))
			      db)))))
	 (db            (if (dbmod:need-on-disk-db-handle)
			    (open-the-db)
			    #f))
	 (db            ;; (if (dbmod:need-on-disk-db-handle)
			    (open-the-db))
;;			    #f))
	 (tables       (db:sync-all-tables-list keys)))
    (dbr:dbstruct-inmem-set!    dbstruct inmem)
    (dbr:dbstruct-ondiskdb-set! dbstruct db)
    (dbr:dbstruct-dbfile-set!   dbstruct dbfullname)
    (dbr:dbstruct-inmem-set!     dbstruct inmem)
    (dbr:dbstruct-ondiskdb-set!  dbstruct db)
    (dbr:dbstruct-dbfile-set!    dbstruct dbfullname)
    (dbr:dbstruct-dbfname-set!   dbstruct dbfname)
    (dbr:dbstruct-sync-proc-set! dbstruct
				 (lambda (last-update)
				   (if db
				       (sync-gasket tables last-update inmem db
						    dbfullname syncdir))))
				   ;; (if db
				       (dbmod:sync-gasket tables last-update inmem db
						    dbfullname syncdir))) ;; )
    ;; (dbmod:sync-tables tables #f db inmem)
    ;; (if db
    (if db (sync-gasket tables #f inmem db dbfullname 'fromdest))
    (dbmod:sync-gasket tables #f inmem db dbfullname 'fromdest) ;; ) ;; load into inmem
    (dbr:dbstruct-last-update-set! dbstruct (current-seconds)) ;; should this be offset back in time by one second?
    dbstruct))

;;    (if (eq? syncdir 'todisk) ;; sync to disk normally, sync from in dashboard
;;        (dbmod:sync-tables tables last-update inmem db)
;;        (dbmod:sync-tables tables last-update db inmem))))

;; direction: 'fromdest 'todest
;;
(define (sync-gasket tables last-update inmem dbh dbfname direction)
(define (dbmod:sync-gasket tables last-update inmem dbh dbfname direction)
  (case (dbfile:sync-method)
    ((none) #f)
    ((attach)
     (dbmod:attach-sync tables inmem dbfname direction))
    ((newsync)
     (dbmod:new-sync tables inmem dbh dbfname direction))
    (else
     (case direction
       ((todest)
	(dbmod:sync-tables tables last-update inmem dbh))
       ((todisk)
	(dbmod:sync-tables tables last-update inmem dbh)
	)
       (else
	(dbmod:sync-tables tables last-update dbh inmem))))))


(define (dbmod:close-db dbstruct)
  ;; do final sync to disk file
  ;; (do-sync ...)

	 (sqlite3:for-each-row
	  (lambda (a . b)
	    (hash-table-set! todat a (apply vector a b)))
	  todb
	  full-sel)
	 
	 ;; first pass implementation, just insert all changed rows
	 
	 (let* ((db                 todb)
                (drp-trigger        (if (member "last_update" field-names)
					(db:drop-trigger db tablename) 
					#f))
		(has-last-update    (member "last_update" field-names))
                (is-trigger-dropped (if has-last-update
                                        (db:is-trigger-dropped db tablename)
					#f)) 
		(stmth  (sqlite3:prepare db full-ins))
                (changed-rows 0))
	   (for-each
	    (lambda (fromdat-lst)
	      (mutex-lock! *db-transaction-mutex*)
	      (sqlite3:with-transaction
	       db
	       (lambda ()
		 (for-each ;; 
		  (lambda (fromrow)
		    (let* ((a    (vector-ref fromrow 0))
			   (curr (hash-table-ref/default todat a #f))
			   (same #t))
		      (let loop ((i 0))
			(if (or (not curr)
				(not (equal? (vector-ref fromrow i)(vector-ref curr i))))
			    (set! same #f))
			(if (and same
				 (< i (- num-fields 1)))
			    (loop (+ i 1))))
		      (if (not same)
			  (begin
			    (apply sqlite3:execute stmth (vector->list fromrow))
			    (hash-table-set! numrecs tablename (+ 1 (hash-table-ref/default numrecs tablename 0)))
                            (set! changed-rows (+ changed-rows 1))))))
		  fromdat-lst))))
			    (set! changed-rows (+ changed-rows 1))))))
		  fromdat-lst)))
	      (mutex-unlock! *db-transaction-mutex*))
	    fromdats)
	   
	   (sqlite3:finalize! stmth)
           (if (member "last_update" field-names)
               (db:create-trigger db tablename)))))
               (db:create-trigger db tablename)))
	 ))
     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.
      (for-each 
       (lambda (dat)

			       " SELECT * FROM "fromdb table";"))
		  (stmt8 (conc "UPDATE "todb table" SET ("no-id-fields-str") = (SELECT "no-id-fields-str" FROM "fromdb table" WHERE "todb table".id="fromdb table".id"
			       (if (member "last_update" fields)
				   (conc " AND "fromdb table".last_update > "todb table".last_update);")
				   ");")))
		  (start-ms (current-milliseconds)))
	     ;; (debug:print 0 *default-log-port* "stmt8="stmt8)
	     (if (sqlite3:auto-committing? dbh)
		 (begin
		   (sqlite3:with-transaction
		    dbh
		    (lambda ()
		      (sqlite3:execute dbh stmt1)    ;; get all new rows

		      #;(if (member "last_update" fields)
			  (sqlite3:execute dbh stmt8))    ;; get all updated rows
		      ;; (sqlite3:execute dbh stmt5)
		      ;; (sqlite3:execute dbh stmt4) ;; if it worked this would be better for incremental up
		      ;; (sqlite3:execute dbh stmt6)
		      ))
		   (debug:print 0 *default-log-port* "Synced table "table
				" in "(- (current-milliseconds) start-ms)"ms"))
		 (debug:print 0 *default-log-port* "Skipping sync of table "table" due to transaction in flight."))))
	     ;; (if (sqlite3:auto-committing? dbh)
	     ;; (begin
	     (mutex-lock! *db-transaction-mutex*)
	     (sqlite3:with-transaction
	      dbh
	      (lambda ()
		(debug:print-info 0 *default-log-port* "Sync from "fromdb table" to "todb table" using "stmt1)
		(sqlite3:execute dbh stmt1)    ;; get all new rows
		
		#;(if (member "last_update" fields)
		(sqlite3:execute dbh stmt8))    ;; get all updated rows
		;; (sqlite3:execute dbh stmt5)
		;; (sqlite3:execute dbh stmt4) ;; if it worked this would be better for incremental up
		;; (sqlite3:execute dbh stmt6)
		))
	     (debug:print 0 *default-log-port* "Synced table "table
			  " in "(- (current-milliseconds) start-ms)"ms") ;; )
	     (mutex-unlock! *db-transaction-mutex*)))
	     
	 ;; (debug:print 0 *default-log-port* "Skipping sync of table "table" due to transaction in flight."))))
	 table-names)
	(sqlite3:execute dbh "DETACH auxdb;"))))

;; FAILED ATTEMPTS

	     ;; (if (not (has-last-update dbh table))
	     ;;     (sqlite3:execute dbh (conc "ALTER TABLE "table" ADD COLUMN last_update INTEGER;")))

	    (debug:print 0 *default-log-port* "FATAL: Could not start a tcp server, giving up.")
	    (exit 1))
	  (if (not (tt-port ttdat)) ;; no connection yet
	      (begin
		(thread-sleep! 0.25)
		(loop (+ count 1))))))
    
    ;; load or reload the data into inmem db before
    ;; ((dbr:dbstruct-sync-proc dbstruct) (dbr:dbstruct-last-update dbstruct))
    ;; (dbr:dbstruct-last-update-set! dbstruct (- (current-seconds) 1))
    (tt:create-server-registration-file ttdat dbfname)
    ;; now start watching the last-access, if it hasn't been touched
    ;; in over ten seconds we exit
    (thread-sleep! 0.05) ;; any real need for delay here?
    (let loop ()
      (let* ((servers (tt:get-server-info-sorted ttdat dbfname))
	     (ok      (cond