[TYPO3-english] backend hangs randomly

Nicola Cerchiari nicola.cerchiari at gmail.com
Tue Feb 22 14:07:32 CET 2011


Hi Bjorn,
thank you for your advices.
i'd like to update to what system administrators are finding out while we
write.
They just finished to check db perfomarce finding no lack of them: no
"infinite" locking or huge blocking queries.

Moreover I'm sorry but i did not really understand what did u mean in the
stalling locking point, can you please explain a little more fo "human
beings" ;)

Thanks,
Nik

2011/2/22 Bjoern Pedersen <bjoern.pedersen at frm2.tum.de>

> Am 22.02.2011 11:40, schrieb Nicola Cerchiari:
> > Hi to all,
> > First time here suggested by friends of the italian mialing list; i'm
> > encountering a very annoying problem of which I can find no solutions.
> >
> > The problem is that randomly during day calling any backend action hang
> the
> > browser on "waiting for response..." and the only solution left is to
> stop
> > the call, wait several minutes and then everything is back to normal
> until
> > it happens again.
> > For example the same action works for 2 hours and then all of a sudden
> > hangs. Even accessing to backend login page sometimes hangs.
> > I've tested the same website and core on my test machines and I never
> > encounter any problem.
> > I give you some data in other to better understand the situation:
> > - php 5.2.x with all libraries needed
> > - mysql 5.1.55 in replication master/slave (just updated)
> > - 2 balanced webserver apache/redhat (on a vmware virtualized farm)
> > - filesystem of webserver ron a shared NAS
> > - version of typo3 on which the problem is encountered: 4.4.6 and 4.5.0
> >
> > The matter is that when backend works, works pretty fast, but the nall of
> a
> > sudden with apparently no reason it hangs.
> >
> > System admnistrators of the infrastructure suggested at first that there
> was
> > a "strangly" large amount of calls in TIME_WAIT state, then they
> suggested
> > maybe the mysql server is not tuned sufficiently to stand the increasing
> > requests (consider that this infrastructure receive >50.000 user visit a
> > day) and they will try a fine tuning in the next day.
> >
> > What i'm looking for is to understand if the problem is due to Typo3 (i
> > don't think so) or there is some problem in our infrastructure.
> >
> > Any ideas?
> >
> >
> > Thank you in advance,
> > Nicola
>
> Possible causes: clearing cache: lots of rather slow delete queries on
> db -> there is a extension to use truncate table for clearing the cache.
>
> stalling locking ( there are some race conditions left in the locking
> code, check the  bugtracker)
>
> DB-backup not excluding the cache tables: huge amount of data with table
> locking, so lots of db request waiting foe the lock to become released.
>
> Björn
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