I'm using PostgreSQL on WinNT to support (along with Zope) several websites. I've currently got postmaster running as an NT service by wrapping it with the 'invoker' utility, but I'd prefer to have it run directly as a service so that it can be stopped cleanly. I now know the basics of how to extend a program to make it run directly as an NT service, as I've enhanced the Cygipc (Cygwin) 'ipc-daemon' process to do just that (and I've submitted the patch to the current maintainer of Cygipc). So now I'd like to do the same for postgres/postmaster, but I want you all to vet this plan before I invest much more time. For me, the fundamental question is: If I create a patch that implements this function, what will it take to get it into the main CVS version? Will some established PostgreSQL developer offer to review/champion/mentor my work? Expected plan of operation: 1) Administrator runs 'postgres --install-as-service'. Program installs NT registry entries and calls Windows APIs to register the service, leaving it ready for 'automatic' startup, but not starting the service. The ImagePath key value uses exactly the full path of the 'postgres' program that did the install. After installing the service the program returns immediately. 2) When starting the service from, say, the Services Control Panel, postgres is invoked with a new '--service' command-line flag. When the postgres program starts running it looks for this option right away (much like '-boot') and, finding it, starts up in postmaster mode and passes on the --services flag, causing the postmaster code to do the necessary magic to start up as an NT service. This does not involve any additional forks; the process splits into a supervisory thread and a main thread that runs the existing main work loop. 3) When the service is stopped, the supervisory service thread sends some kind of event/signal/semaphore/... to the main work thread, causing that thread to shut down as if 'pg_ctl -m fast stop' had been called [is this a good choice?]. 4) Administrator runs 'postgres --remove-as-service'. The program removes the registry data for the service and calls APIs to completely remove the service. It shuts down the service first if it's already running. Then it quits. Design questions: a) The 'install' and 'remove' code is quite bulky, although simple. Is it OK to create a new source file for it, rather than working it into some existing file? b) How can the service log error messages? Is there any syslog type facility? If not, is it OK to include a new output interface that would log to the NT event log? Or is there some better scheme? c) What is a good way for the supervisory thread to communicate with the main thread and shut it down cleanly? (I haven't studied the code to find the main wait/select loop yet. Sorry.) d) How can we insure that the ipc-daemon service starts before the postgres/postmaster service? I believe that NT has some facility that allows one service to request start-up of another service, but I have no idea how to make that happen. Your feedback on this plan is more than welcome. I'm willing to put time into getting this working, but only if I get some support from you all. -- Fred Yankowski [EMAIL PROTECTED] tel: +1.630.879.1312 Principal Consultant www.OntoSys.com fax: +1.630.879.1370 OntoSys, Inc 38W242 Deerpath Rd, Batavia, IL 60510, USA
