memcached crashing

[Brad Fitzpatrick]

Scary.

Run it with -r to increase core file size, and make sure the user you run
it as has permission to write to the directory you start it from. (with -r
it won't chdir to /)

Then with the core file, we can inspect it with gdb.

But maybe it's not crashing and just quitting, like the event loop is
ending.

In that case, run it in the foreground but with strace in front of it:

strace ./memcached .....

Then paste what you see as its final output.



On Wed, 30 Jun 2004, Jon Valvatne wrote:

> Ok; thanks for the heads-up. I recompiled libevent without rtsig
> support, but that doesn't seem to have changed anything at all. Still
> random crashes and refused connections.
>
> Is there any way to get any sort of debug information out of memcached
> when it crashes?
>
> Jon
>
> ----------------------------------------------------------------------
> On Tue, 29 Jun 2004 21:10:53 -0700 (PDT)
> Brad Fitzpatrick <brad@danga.com> wrote:
>
> > Do *not* use libevent's rtsig support.  I thought he removed that
> > given
> > how buggy it was.  Three really smart people worked on it for quite
> > some
> > time without getting it anywhere near reliable.  It's just a crap
> > interface and it was never made to work with libevent.
> >
> > Use poll if you must, but epoll's really the best.
> >
> > - Brad
> >
> >
> > On Wed, 30 Jun 2004, Jon Valvatne wrote:
> >
> > > Hello,
> > >
> > > I've been using memcached to add some caching to a production system
> > > to
> > > speed things up. Everything worked smoothly on my test box, but I
> > > ran
> > > into nothing but problems when trying to go live with the changes:
> > > Memcached would just die randomly, without any error message
> > > whatsoever,
> > > within minutes of startup. And even while it was running and
> > > accepting
> > > some connections, other connections appeared to be randomly refused.
> > >
> > > The only difference between the test box and the production system
> > > is
> > > that one is running Fedora Core 2, and the other Redhat 9. Before I
> > > try
> > > to debug the situation more, I would like to ask: Does anyone here
> > > have
> > > any experience running memcached with Redhat 9? There's obviously no
> > > epoll support, so I compiled the latest libevent with --with-rtsig,
> > > and
> > > I'm assuming that's what memcached is using. Is this just inherently
> > > buggy, or so poor-performing that my system with about a hundred
> > > connections and several operations per second will cause the problem
> > > I'm
> > > seeing?
> > >
> > > One thing that worried me were the test results when compiling
> > > libevent:
> > >
> > > Running tests:
> > > KQUEUE
> > > Skipping test
> > > POLL
> > >  test-eof: OKAY
> > >  test-weof: OKAY
> > >  test-time: OKAY
> > >  regress: FAILED
> > > SELECT
> > >  test-eof: OKAY
> > >  test-weof: OKAY
> > >  test-time: OKAY
> > >  regress: FAILED
> > > RTSIG
> > >  test-eof: OKAY
> > >  test-weof: OKAY
> > >  test-time: OKAY
> > >  regress: FAILED
> > > EPOLL
> > > Skipping test
> > >
> > > What are these regress tests, and what would cause them to fail?
> > >
> > > By the way: Is there any way to ask memcached or libevent which
> > > polling
> > > mechanism is being used?
> > >
> > > Thanks in advance,
> > >
> > > Jon Valvatne
> > >
> > >
>
>