Re: [APC-DEV] APC + Apache SIGHUP

Nathan Clemons wrote:

> We do some pretty standard Apache log rotation on our web cluster with
> logrotate; move the file to an archival point, send a SIGHUP to Apache
> so it releases the open file handle, and then bzip2 up the data for
> archival purposes.

I'm almost sure this is an apache thing and nothing apc can really do
about it.

[Thu Oct 08 15:23:27 2009] [notice] SIGHUP received.  Attempting to restart
We hit mshutdown - 9345
apache2: Could not reliably determine the server's fully qualified 
domain name, using 127.0.1.1 for ServerName
We hit minit - 9345

is what my apache2 says. Just to be double+good, I put a couple of
printfs in module init/module shutdown code. And I can see that
a SIGHUP essentially stops and restarts the php modules directly.

> isn't something we particularly like, since we're caching our
> localization data inside of APC (using apc_store). 

So basically the apc module init is called again in the parent
process after it gets a SIGHUP. It's not that apc is clearing
its cache or handling the HUP, apache is essentially doing an
internal soft restart.

http://httpd.apache.org/docs/2.2/stopping.html#hup

> localization data is pulled from. Ideally we'd like to see a staggered
> situation where the servers are not all pulling at the same time, but
> we don't want to change when our logs are rotated as that would
> introduce difficulties in our reporting infrastructure.

I can see your problem, but each of these bits are actually functioning
as they were designed to be.

MSHUTDOWN *has* to cleanup memory because it cannot see into the future
and predict whether an MINIT is to follow.

> Is this a generic artifact of APC and Apache interactions, or is there
> some configuration change I can make to alter this behavior?

I don't think you can change the way it behaves without some non-standard
patching. But I'm open to actually getting your problem solved,
even if it doesn't get into SVN.

Cheers,
Gopal
-- 
If I learn from my mistakes, pretty soon I'll know everything.