yes, at the end jackrabbit is a database.
btw do you have any doc to share on the SharedItemStateManager ?
Stefan Guggisberg wrote:
On 7/15/05, Marcel Reutegger <[EMAIL PROTECTED]> wrote:
Hi Julien,
Julien Viet wrote:
the other ideas would to plug JBoss Cache (distributed transactionnal
cache) in jackrabbit but there are no hooks to
do that so far. My trick about disabling the jackrabbit cache is that I
reimplemented a jackrabbit filesystem on top
of JBoss Portal to provide replication. It worked but some tests are not
passing in jackrabbit suite and I did not check
further (no time). Having such an integration would require I think
modifications in jackrabbit. Perhaps JBoss Cache
should be plugged at the SharedItemState level.
We have ongoing (tough private coffee break) discussions here at day
about clustering. The reason why we are not pushing such a feature right
now is, that it would require a redesign of one of the very central core
pieces of jackrabbit. I can only speak for myself, but I rather want to
release a stable single instance version of jackrabbit, than a release
with clustering support that turns out to be not reliable.
If you think about it, JBoss Cache does already what jackrabbit is doing
is some ways. It is possible to configure it
to have a cache loader that can load and store cache entries. It is
comparable to SharedItemStateCache and PersistenceManager
you have in your codebase. The difference is that the cache can be
replicated and also provide a configurable isolation level, also
we are in the process of adding optimistic locking.
I had a look at JBoss Cache the other day, and I think it looks
promissing indeed.
i had a quick glance at JBoss Cache as well. i agree that it looks
promising, but not for use in jackrabbit's core.
for one JBoss Cache is hierarchical (i.e. path-based) whereas jackrabbit's
internal data model is flat (id-based).
i don't think that crucial components at the very core should be pluggable.
the contract of SharedItemStateManager is quite complex. if it's not
implemented correctly the stability and integrity of the repository is at
great risk. do you know of any rdbms engine that supports pluggable
caches for its internal row buffers? i don't.
With the risk that someone will probably try to kill me on monday I
;)
opened a jira issue to start a more technical discussion about
clustering and what is needed to make this possible in jackrabbit:
http://issues.apache.org/jira/browse/JCR-169
good starting point!
cheers
stefan
regards
marcel
--
Julien Viet
JBoss Portal Lead Developer
