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From Travis Savo <ts...@IFILM.com>
Subject RE: Store surviving a shutdown
Date Tue, 18 May 2004 21:02:15 GMT
That would happen when the LRUMapJCS was written to disk, and then the
LRUMapJCS class file changed. Presently there's no good solution for
migrating from older versions of classes to new ones with straight Java
Object Serialization.

My suggestion would be to delete your disk cache, as this will force the new
version of the class to be written out to disk. You'll need to do this any
time your LRUMapJCS class changes (or any classes being serialized to disk
for that matter).

If class migration is a requirement (i.e. you need to be able to upgrade
your JCS with LRUMapJCS changes without loosing your disk cache), you might
want to look into some of the Java XML Serialization frameworks available,
as I seem to have a vague memory of one of them supporting class migration.
It would be fairly trivial to create a new disk cache which used it instead.

-Travis Savo


-----Original Message-----
From: Carsten Ziegeler [mailto:cziegeler@s-und-n.de]
Sent: Tuesday, May 18, 2004 1:46 PM
To: 'Turbine JCS Developers List'
Subject: RE: Store surviving a shutdown


I think I found the problem now:

During reading the keys the following exception occurs in readObject in
IndexedDisk:

ClassCastException: local class incompatible: stream classdesc
serialVersionUID = 7888269624850553887, local class serialVersionUID =
776964015449842672

And classname is org.apache.jcs.auxiliary.disk.LRUMapJCS

Hmm...

Carsten 

> -----Original Message-----
> From: Carsten Ziegeler [mailto:cziegeler@s-und-n.de] 
> Sent: Tuesday, May 18, 2004 4:15 PM
> To: 'Turbine JCS Developers List'
> Subject: RE: Store surviving a shutdown
> 
> Hi,
> 
> to complete the picture, attached is the configuration we use.
> 
> Carsten 
> 
> > -----Original Message-----
> > From: Carsten Ziegeler [mailto:cziegeler@s-und-n.de]
> > Sent: Tuesday, May 18, 2004 2:31 PM
> > To: 'Turbine JCS Developers List'
> > Subject: RE: Store surviving a shutdown
> > 
> > Hi Aaron,
> > 
> > yes we are running the latest version from CVS and yes we 
> get the two 
> > files and they are both not empty.
> > 
> > But on startup the files are overwritten. Is there any 
> configuration 
> > for this perhaps?
> > 
> > Carsten
> > 
> > > -----Original Message-----
> > > From: Aaron Smuts [mailto:aasmuts@wisc.edu]
> > > Sent: Tuesday, May 18, 2004 2:25 PM
> > > To: 'Turbine JCS Developers List'
> > > Subject: RE: Store surviving a shutdown
> > > 
> > > The latest jcs version if shutdown properly, should write 
> two files 
> > > per region.  One called keys the other data.  One startup 
> it should 
> > > read the keys into memory and everything in the data folder
> > should be
> > > available just as before shutdown.
> > > 
> > > You need to make sure that the elements in the regions are not 
> > > expiring also.
> > > 
> > > Are you getting the two files?  If not, did you build the latest 
> > > version of jcs from source?
> > > 
> > > Cheers,
> > > 
> > > Aaron
> > > 
> > > 
> > > > -----Original Message-----
> > > > From: Carsten Ziegeler [mailto:cziegeler@s-und-n.de]
> > > > Sent: Tuesday, May 18, 2004 5:36 AM
> > > > To: 'Turbine JCS Developers List'
> > > > Subject: RE: Store surviving a shutdown
> > > > 
> > > > Just an additional info:
> > > > It seems that the files are written properly on 
> shutdown, but on 
> > > > startup they are overwritten with empty files.
> > > > 
> > > > Carsten
> > > > 
> > > > > -----Original Message-----
> > > > > From: Upayavira [mailto:uv@upaya.co.uk]
> > > > > Sent: Tuesday, May 18, 2004 9:46 AM
> > > > > To: turbine-jcs-dev@jakarta.apache.org
> > > > > Subject: Store surviving a shutdown
> > > > >
> > > > > Hello, another Cocooner popping in for a visit!
> > > > >
> > > > > In our explorations of JCS, one thing I believe that was
> > > said about
> > > > > it is that the store doesn't persist through a shutdown.
> > > > >
> > > > > Now, the current (slightly buggy) implemention within
> > > Cocoon does. 
> > > > > Is there any way to make it persists through a restart,
> > > or to make
> > > > > it configurable?
> > > > >
> > > > > The main usecase for Cocoon is running within a 
> servlet, where 
> > > > > arguably surviving a shutdown isn't crucial. However,
> > > Cocoon can be
> > > > > used from the command line to statically generate web
> > sites. For
> > > > > this, a working persistent cache that survives 
> shutdown can be 
> > > > > invaluable. Each time you run it, it can check to see
> > > whether a page
> > > > > in the cache is up-to-date, and if so, not bother
> > generating the
> > > > > page. This should be able to offer a great performance
> > > improvement
> > > > > (but didn't because our previous implementation of a 
> persistent 
> > > > > store was slow). So you'd make me a happy man if you 
> gave me a 
> > > > > responsive persistent store that could survive a shutdown.
> > > > >
> > > > > Regards, Upayavira
> > > > >
> > > > >
> > > > >
> > > > >
> > > > >
> > > > >
> > > 
> > 
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> > > > >
> > > > >
> > > > 
> > > > 
> > > > 
> > > 
> > 
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> > > 
> > > 
> > > 
> > 
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> > 
> > 
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> 
> 


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