Terracotta Discussion Forums (LEGACY READ-ONLY ARCHIVE)

Currently we are using a very high performance object store, a bit like jdbm.
Would it be possible to use such a store instead of an SQL-based database?
I think that would be desirable from the performance perspective.

Hi. I'm not sure I follow. Where would you like to plug in a jdbm-like-store?

Cheers,
-p

_________________
Patrick Calahan
Director, Product Management
Terracotta, Inc.

OK, let me provide a little more info. We get data files delivered in XML-format, which we parse and store in a data and index store. To be honest, not exactly jdbm but bdb-je which is already known to Terracotta actually (though we use a more recent version). Now bdb-je doesn't offer replication yet, so I guess there lies an opportunity for Terracotta.
Besides that ... for another project we are using Lucene, which is also quite interesting to work with in a distributed setup. It's even further away from JDBC, simply using a bunch of plain files, which for replication requires taking snapshots and re-creating searchers etc. We have a solution for that, but it would be nice to make it simpler and/or more robust.

you should check out SOLR for lucene searching/indexing..it supports a index replication across nodes :)..

http://incubator.apache.org/solr/

i don't think terracotta is the right technology to build your persistence storage on top of..(RDMS is meant for that).

It probably wouldn't surprise you that the answer is a bit more of a "depends".

Terracotta is purpose built to cluster in-memory object graphs. For that reason, instead of using an in-memory relational database, I would definitely recommend Terracotta. But it depends, if you are truly looking for the capabilities of a true RDBMS, but want it in memory, we are not built for that. If, on the other hand, you are using an OODB just because you need to store your objects, Terracotta provides durable in-memory storage, and there is no need to concern yourself with how to marshal and un-marshal objects into the OODB.

I looked at SOLR. From my reading, it appears as though it writes the Lucene index file(s) to disk and then periodically rsyncs them to other nodes in the cluster. If I am incorrect, please feel free to explain it in more detail.

We have, in fact, just recently produced a working prototype that clusters in-memory Lucene index files. This is radically different than the approach used by SOLR, as the changes to the index files when clustered by Terracotta are immediate and there is no requirement to implement additional infrastructure such as cron jobs, logins etc. that an rsync setup would require.

For more information, have a look at our Common Use Cases

Best Regards,

Taylor

I 100% agree with everything you said, it "depends" :),

You are correct that SOLR resync. nodes on cluster from a "master" repostiory..each node writes to this repository only, while keeping a copy that is resynced.