Horton

Re: [HACKERS] Weaker shmem interlock w/o postmaster.pid

Noah Misch <noah@leadboat.com>

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From: Noah Misch <noah@leadboat.com>
To: Thomas Munro <thomas.munro@gmail.com>
Cc: Daniel Gustafsson <daniel@yesql.se>, Kyotaro HORIGUCHI <horiguchi.kyotaro@lab.ntt.co.jp>, "9erthalion6@gmail.com" <9erthalion6@gmail.com>, "sfrost@snowman.net" <sfrost@snowman.net>, "pgsql-hackers@postgresql.org" <pgsql-hackers@postgresql.org>
Date: 2019-05-01T00:57:11Z
Lists: pgsql-hackers 
On Tue, Apr 30, 2019 at 10:47:37PM +1200, Thomas Munro wrote:
> On Mon, Apr 22, 2019 at 4:59 AM Noah Misch <noah@leadboat.com> wrote:
> > On Thu, Apr 18, 2019 at 04:30:46PM +1200, Thomas Munro wrote:
> > > This causes make check-world to deliver a flurry of pop-ups from
> > > macOS's built-in Firewall asking if perl should be allowed to listen
> > > to all interfaces [...].
> >
> > That is unfortunate.  The "Allowing specific applications" section of
> > https://support.apple.com/en-us/HT201642 appears to offer a way to allow perl
> > permanently.  Separately, it wouldn't cost much for us to abandon that check
> > on !$use_tcp (non-Windows) configurations.
> 
> My system is set up not to allow that and I suppose I could go and
> argue with my IT department about that, but I'm interested in your
> second suggestion if the test is in fact not serving any useful
> purpose for non-Windows systems anyway.  Do you mean like this?
> 
> --- a/src/test/perl/PostgresNode.pm
> +++ b/src/test/perl/PostgresNode.pm
> @@ -1098,17 +1098,12 @@ sub get_new_node
>                 # native Perl (https://stackoverflow.com/a/14388707),
> so we also test
>                 # individual addresses.
>                 #
> -               # This seems like a good idea on Unixen as well, even
> though we don't
> -               # ask the postmaster to open a TCP port on Unix.  On Non-Linux,
> -               # non-Windows kernels, binding to 127.0.0.1/24
> addresses other than
> -               # 127.0.0.1 fails with EADDRNOTAVAIL.
> -               #

Deleting that comment paragraph isn't quite right, since we're still testing
127.0.0.1 everywhere.  The paragraph does have cause to change.

>                 # XXX A port available now may become unavailable by
> the time we start
>                 # the postmaster.
>                 if ($found == 1)
>                 {
> -                       foreach my $addr (qw(127.0.0.1 0.0.0.0),
> -                               $use_tcp ? qw(127.0.0.2 127.0.0.3) : ())
> +                       foreach my $addr (qw(127.0.0.1),
> +                               $use_tcp ? qw(0.0.0.0 127.0.0.2 127.0.0.3) : ())

This is what I meant, yes.

>                         {
>                                 can_bind($addr, $port) or $found = 0;
>                         }

Commits

  1. Probe only 127.0.0.1 when looking for ports on Unix.

  2. Don't write to stdin of a test process that could have already exited.

  3. Test both 0.0.0.0 and 127.0.0.x addresses to find a usable port.

  4. MSYS: Translate REGRESS_SHLIB to a Windows file name.

  5. MSYS: Skip src/test/recovery/t/017_shm.pl.

  6. When Perl "kill(9, ...)" fails, try "pg_ctl kill".

  7. Consistently test for in-use shared memory.

  8. Revert "Consistently test for in-use shared memory."

  9. Silence -Wimplicit-fallthrough in sysv_shmem.c.

  10. Make src/test/recovery/t/017_shm.pl safe for concurrent execution.

  11. Update HINT for pre-existing shared memory block.

  12. Add WL_EXIT_ON_PM_DEATH pseudo-event.

  13. The default values for shared_buffers and max_connections are now 1000

  14. XLOG (and related) changes:

  15. Significant cleanups in SysV IPC handling (shared mem and semaphores).