[ic] workaround found for 99%CPU usage problem in Vend/SessionFile.pm: "::uneval($ref);" fixes it

Steffen Dettmer interchange-users@interchange.redhat.com
Thu Nov 15 06:03:18 2001


* Mike Heins wrote on Wed, Nov 14, 2001 at 19:58 -0500:
> Quoting Steffen Dettmer (steffen@dett.de):
> > You're right, sorry. It's an SuSE 7.0 distribution:
> > Linux stella 2.2.16-SMP #1 SMP Wed Aug 2 20:01:21 GMT 2000 i686 unknown
> > with the old Perl 5.005_03.
> 
> Aha. This could be part of the problem, particularly if you do
> have multiple processors.

Yep, this machine has two CPUs (Pentium III (Coppermine) 866). 

 [...] 
> If it is Linux, this is probably not an issue other than the general
> out-of-datedness of your software.

Hum, but of course it's not possible to update to each
distribution plus all upgrades always on every host.

> Aha. That is it -- flock() doesn't work across NFS filesystems.
> And it won't work at all if you don't have lockd running; even
> then you should set LockType to "fcntl" if you want to still
> try NFS. 

I'll try it out. Thank you!

> In any case, I am certain if it moves to a local file system
> the problem will disappear.

Is it enough to move the catalog/catname/session to a local file
system? If possible I would like to keep the catalog on NFS
(beacuse of backups and so on). Do you think it's enough to make
session a symlink to something local?

> This is just timing problem. If we can't lock reliably, file-based
> sessions simply will not work. You could move to DBI sessions.

This would be an alternative, but since I have only a single web
server I think it's a lot more performant to have file based
sessions, correct? So I would prefere to have the sessions on a
local file system.

Thank you for your help!

oki,

Steffen

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