jakarta-jcs-dev mailing list archives

Site index · List index
Message view « Date » · « Thread »
Top « Date » · « Thread »
From Travis Savo <ts...@IFILM.com>
Subject RE: outstanding issues?
Date Wed, 14 Apr 2004 19:19:42 GMT
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



---------------------------------------------------------------------
To unsubscribe, e-mail: turbine-jcs-dev-unsubscribe@jakarta.apache.org
For additional commands, e-mail: turbine-jcs-dev-help@jakarta.apache.org

---------------------------------------------------------------------
To unsubscribe, e-mail: turbine-jcs-dev-unsubscribe@jakarta.apache.org
For additional commands, e-mail: turbine-jcs-dev-help@jakarta.apache.org


Mime
View raw message