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From Travis Savo <ts...@IFILM.com>
Subject RE: outstanding issues?
Date Wed, 14 Apr 2004 23:14:53 GMT
Yes. If you read the posts from a week or two ago on the JCS users list
there was a gentleman who was getting the wrong objects returned from gets
when one of his lateral caches was restarted.

-Travis Savo

-----Original Message-----
From: Aaron Smuts [mailto:aasmuts@wisc.edu]
Sent: Wednesday, April 14, 2004 4:10 PM
To: 'Turbine JCS Developers List'
Subject: RE: outstanding issues?


I didn't think that the problem was with the get method.  

Was someone having another problem with the lateral?

Aaron

> -----Original Message-----
> From: Aaron Smuts [mailto:aasmuts@wisc.edu]
> Sent: Wednesday, April 14, 2004 6:09 PM
> To: 'Turbine JCS Developers List'
> Subject: RE: outstanding issues?
> 
> if (socket.getInputStream().available() > 0) {
>       socket.getInputStream().read(new
> byte[socket.getInputStream().available()]);
>  }
> 
> I noticed this addition before writing in the SendAndReceive method of
> the LateralTCPSender class.  Is this all you added to the lateral?
> 
> This method is only used by get requests to other laterals.
> 
> There must be something I overlooked.
> 
> Aaron
> 
> Is this all you added?
> > -----Original Message-----
> > From: Travis Savo [mailto:tsavo@IFILM.com]
> > Sent: Wednesday, April 14, 2004 2:20 PM
> > To: 'Turbine JCS Developers List'
> > Subject: RE: outstanding issues?
> >
> > Definitely check out the EHCache tests. They have several tests
which
> > expose
> > the flaws.
> >
> > The disk locking problem happens only under very heavy load. The
> > implementation taken from EHCache doesn't exhibit the same problems,
> only
> > requires one file per region, and can be easily and reliably be made
> > persistable across restarts. Is there something wrong with using it?
> >
> > As covered in my prior posts with patches, the problem with lateral
> > distribution is the LateralTCPService can get a socket stream with
> dirty
> > data from prior requests, leading to mismatched objects returned on
> > lateral
> > get. My patch demonstrates an obvious place to flush the buffer.
> >
> > The memory leak in memory cache happens when the linked list becomes
> > inconsistent with the map. EHCache tests to expose this suggest the
> > problem
> > is with removeAll, but I've seen it with just get/put/remove. The
LRU
> > memory
> > store implementation from EHCache uses an java.util.LinkedHashMap,
or
> if
> > it's not available, a org.apache.commons.collections.map.LRUMap,
> thereby
> > dramatically reducing the complexity of the code, and eliminating
> > opportunities for the linked list and map to get out of sync.
> >
> > It's also 79% faster for the 'insert 5 million typical
CacheElements,
> then
> > get each of them by key' test, and 293% faster for the 'insert 5
> million
> > typical CacheElements and get each of them by key, then remove them
> one at
> > a
> > time by key' (stastics borrowed from
> >
>
http://ehcache.sourceforge.net/documentation/index.html#physicalstores).
> > Again, is there something wrong with using it? Why go to all the
work
> of
> > fixing a complex design when a simpler, faster one exists, and is
> working
> > without problems?
> >
> > The other issues I'm aware of is with RemoteCache, where removes
will
> > generate exponential remove requests. I'm working on a patch for it
> from
> > my
> > code base, as well as the change from byte to integer for cache
ID's,
> > which
> > will cause problems with 2 or more remote caches under flakey
network
> > conditions.
> >
> > -Travis Savo
> >
> >
> >
> > -----Original Message-----
> > From: Aaron Smuts [mailto:aasmuts@wisc.edu]
> > Sent: Wednesday, April 14, 2004 11:41 AM
> > To: 'Turbine JCS Developers List'
> > Subject: outstanding issues?
> >
> >
> > I want to knock out any remaining issues.
> >
> > Can someone let me know if they can get the disk cache to lock.  I
> can't
> > make it happen.
> >
> > Can someone explain the purported problem with the lateral
> distribution.
> >
> > Was the "memory leak" in the memory cache just the problem with
> expired
> > elements not getting removed.  If so, it is solve.  If not, can
> someone
> > explain it to me.
> >
> > If you are aware of any other issues, please let me know and I'll
work
> > on them.
> >
> > Thanks,
> >
> > Aaron
> >
> >
> >
> >
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