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From "Spinka, Kristofer" <kspi...@style.net>
Subject ["PATCH"] STATUS: fcntl() oddness on Solaris
Date Thu, 27 Mar 2003 07:27:51 GMT
I would like to close the following issue with a README addition.

Excerpt from STATUS:
    * fcntl() oddness on Solaris.  Under high loads, fcntl() decides to
      return error code 46 (ENOLCK).

      httpd (prefork MPM) error log says (predictably):

      (46)No record locks available: couldn't grab the accept mutex

      All of the children report this and subsequently exits.  httpd is
      hosed.  AFAICT, this does not look to be an out-of-fds error.

      Solaris's man page says:
           The  cmd argument is F_SETLK, F_SETLK64, F_SETLKW,  or
           F_SETLKW64  and  satisfying the lock or unlock request
           would result in the number of locked  regions  in  the
           system exceeding a system-imposed limit.

      Justin says: What is this system-imposed limit and how do we
change it?
                   This gives me more rationale for switching the
                   interprocess lock mechanism to pthread (if

  The system imposed default limit of outstanding lock requests is 512.
You can verify this by, in a contemporary version of Solaris:

	# mdb -k
	> tune_t_flckrec/D
	tune_t_flckrec: 512

  This can be increased by adding the following to /etc/system:

	set tune_t_flckrec=1024

  and rebooting.

  Of course "1024" can be any reasonable limit, although I do not know
what "reasonable" should be, so be conservative, only increase this as

  If someone would please test this on a system known to break that
would be great.  In addition it is mentioned that *all* of the children
report this, is it actually all of them, or all of them after a certain


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