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From "Tomislav Randjic" <tomislav.rand...@smartsol.co.yu>
Subject RE: bdb-persistence & db-persistence in contrib
Date Fri, 14 Oct 2005 14:14:57 GMT
Hi to all,

> i'd like to propose the following:
> - move the bdb-persistence & db-persistence code from
>   contrib to core
> - change default configuration to use DerbyPersistenceManager
>   (db-persistence) instead of filesystem-based 
> ObjectPersistenceManager
> - remove CQFileSystem from project.xml and default configuration

I agree completely. Not having any transactional pm in jackrabbit is
something I miss the most now. Also, it would be nice to see db-pm
implementation which does store blobs in database too, and has 'normal' db
schema instead of serializing everything in one column. I believe default db
pm need a little improvement as JCR can use RDBMS in a better way, and am
ready to help if this makes any sense to you..

I had problems testing JCR's MySQL db pm impl. With more than ~1000 child
nodes on root node - MySQL blob is 64k and serailized child node data could
not be written. Switching it to longblob fixed that problem, but I think
this 'serailized' approach is not performance wise. As I could see, there is
ORM pm in the works (btw, I don't see the point of it in case of JCR: JSR ->
ORM -> RDBMS -- we need JSRRM :) but some sort schema like in ORM pm could
be used for default DB pm. I think this could be much faster than present db
pm impl.

With blob properties on FS - I am aware that very large blobs are problem
with some RDBMS. As I need some sort of repository for new DMS with
potentially very large data, we are in process of testing slicing large data
into multiple pages - blob columns in DB. I believe, it could preserve a lot
of memory in typical Web based *MS scenario and yet keep everything in DB
which is in my opinion better than DB/FS approach for many reasons. 

Tomislav Randjic

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