Re: postmaster dead but backends still running?

On Thu, 19 Jun 2003, Tom Lane wrote:

> Charles Hornberger <charlie@hss.caltech.edu> writes:
> > However, I think I know the cause (though I haven't tested to see if this
> > indeed causes the postmaster to die): A few hours before I noticed that
> > the postmaster was dead, one of the sysadmins made a typo that caused an
> > NFS mount to become unavailable -- the very NFS mount that held the
> > postgres executable (all our Solaris boxes share the same executables). So
> > the theory is that the postmaster tried to fork() a process using a
> > non-existent executable, and died as a result. Does this make any sense?
>
> A fork() failure would not cause the postmaster to die (it's not
> uncommon to see fork() failures due to resource limits, so this path is
> really pretty well tested).  I'm not familiar enough with Solaris to know
> whether other fatal error conditions might arise in this scenario.
> (I know HPUX gets rather unhappy if you try to delete an executable file
> or shared library that's in use by live processes...)  But the trouble
> with that line of thought is that the postmaster and the backends are
> all the same executable; if the postmaster went south because of loss of
> the executable file, I'd expect the backends not to survive it either.
> Unless maybe the backends weren't actually doing anything --- is it
> possible that the connected clients had issued no commands in the whole
> episode?
>

No, that's not possible; the backends that were up & running were
definitely in active use (serving a web site). Sorry I can't be of more
help -- I'm not familiar w/ Solaris, either. But if there are other places
I should look for error messages, I'm happy to go poking around ...

-Charlie