sonewconn: pcb 0xfffff801efdd1000: Listen queue overflow: 31 already in queue awaiting acceptance

David Benfell benfell at
Tue Mar 17 04:45:18 UTC 2015

On Mon, Mar 16, 2015 at 05:01:45PM -0700, Charles Swiger wrote:
> There's an apc.php script which will look at your APC stats.
It appears not to be compatible with php 5.5, which I guess raises the
question of why I'm needing to adjust this value at all. In any event,
I raised it to 2048M and *this* time didn't see a recurrance. We shall

> >> The listen queue overflow means that your system is failing to process
> >> incoming requests fast enough to keep up.  The bottleneck could be
> >> on a resource like CPU or memory, or serialization against a database
> >> table, or something else.  (You'll want to identify the bottleneck.)

I found this article:

It suggests a number of changes to sysctl oids (including a couple of,
I guess, obsolete ones). I've imported these. I don't think my sites
are really high traffic (I should be rich and famous if they were,
right?) but the box seems able to handle it.
> > 
> > Interesting. htop says I've got plenty of memory and CPU--it's a new
> > server and I went big. That would seem to suggest mysql may not be
> > performing well, which is a very strong possibility. Until relatively
> > recently, I was trying to run on a VPS and then a rather small hosted
> > server; I don't think I've revisited the mysql configuration since.
> > 
> > Thank you very much. All this helps.
> mysql is a likely candidate, particularly if it was an old setup and has
> not been tuned for the workload.  For example, MyISAM is adequate for
> read-mostly stuff, but table-level locking tends to become a real problem
> if you have more than a single admin instance doing writes.

Looking at that, I'm not sure I dare mess with it. None of this is
code I'm writing myself and the one thing left on that page that I
could do would change the order of updates, which, intuitively more
than anything else, sounds unwise.

But I've installed mysqltuner and so I guess I'll be increasing some
variables until (assuming it ever can be) it is happy.

David Benfell <benfell at>
See if you don't understand the
-------------- next part --------------
A non-text attachment was scrubbed...
Name: not available
Type: application/pgp-signature
Size: 819 bytes
Desc: not available
URL: <>

More information about the freebsd-questions mailing list