CVSROOT:        /cvsroot
Module name:    pgsql-server
Changes by:     [EMAIL PROTECTED]       04/04/12 13:19:18

Modified files:
        src/backend/libpq: pqsignal.c 
        src/backend/port/win32: Makefile sema.c 
        src/backend/postmaster: pgstat.c postmaster.c 
        src/include    : miscadmin.h 
        src/include/libpq: pqsignal.h 
        src/include/port: win32.h 
        src/port       : pgsleep.c 
Added files:
        src/backend/port/win32: signal.c socket.c 

Log message:
        Here's an attempt at new socket and signal code for win32.
        
        It works on the principle of turning sockets into non-blocking, and then
        emulate blocking behaviour on top of that, while allowing signals to
        run. Signals are now implemented using an event instead of APCs, thus
        getting rid of the issue of APCs not being compatible with "old style"
        sockets functions.
        
        It also moves the win32 specific code away from pqsignal.h/c into
        port/win32, and also removes the "thread style workaround" of the APC
        issue previously in place.
        
        In order to make things work, a few things are also changed in pgstat.c:
        
        1) There is now a separate pipe to the collector and the bufferer. This
        is required because the pipe will otherwise only be signalled in one of
        the processes when the postmaster goes down. The MS winsock code for
        select() must have some kind of workaround for this behaviour, but I
        have found no stable way of doing that. You really are not supposed to
        use the same socket from more than one process (unless you use
        WSADuplicateSocket(), in which case the docs specifically say that only
        one will be flagged).
        
        2) The check for "postmaster death" is moved into a separate select()
        call after the main loop. The previous behaviour select():ed on the
        postmaster pipe, while later explicitly saying "we do NOT check for
        postmaster exit inside the loop".
        The issue was that the code relies on the same select() call seeing both
        the postmaster pipe *and* the pgstat pipe go away. This does not always
        happen, and it appears that useing WSAEventSelect() makes it even more
        common that it does not.
        Since it's only called when the process exits, I don't think using a
        separate select() call will have any significant impact on how the stats
        collector works.
        
        Magnus Hagander


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