Mailing-List: contact cygwin-help@sourceware.cygnus.com; run by ezmlm List-Unsubscribe: List-Archive: List-Post: List-Help: , Sender: cygwin-owner@sourceware.cygnus.com Delivered-To: mailing list cygwin@sourceware.cygnus.com To: Horak Daniel cc: "'pgsql-hackers@postgreSQL.org'" , "'cygwin@sourceware.cygnus.com'" , "'Joost Kraaijeveld'" Subject: Re: [HACKERS] backend freezeing on win32 fixed (I hope ;-) ) In-reply-to: Your message of Mon, 16 Aug 1999 11:35:54 +0200 <2E7F82FAC1FCD2118E1500A024B3BF907DED3B@exchange.mmp.plzen-city.cz> Date: Mon, 16 Aug 1999 10:07:00 -0400 Message-ID: <601.934812420@sss.pgh.pa.us> From: Tom Lane Horak Daniel writes: > I think I have fixed the freezing of the postgres backend on Windows NT. Now > it survives 5 regression test in a cycle with some concurrent connections > during running the tests. > It have looked like a problem with initializing the same semaphore for > second time (they are "preinitialized" for performance reasons in > InitProcGlobal() in storage/lmgr/proc.c) They should never be "initialized a second time". And the preallocation is *not* for performance reasons, it is to make sure we can actually get enough semaphores (rather than dying under load when we fail to get the N+1'st semaphore when starting the N+1'st backend). > The fix (made for v6.5.1) is here: > [ Fix consists of diking out preallocation of semaphores by postmaster ] I do not like this patch one bit --- I think it is voodoo that doesn't really have anything to do with the true problem. I don't know what the true problem is, mind you, but I don't think this is the way to fix it. Is it possible that the CygWin environment doesn't have a correct emulation of IPC semaphores, such that a sema allocated by one process (the postmaster) is not available to other procs (the backends)? That would explain preallocation not working --- but if that's it then we have major problems in other places, since the code assumes that a sema once allocated will remain available to later backends. regards, tom lane -- Want to unsubscribe from this list? Send a message to cygwin-unsubscribe@sourceware.cygnus.com