On 08/06/15 17:48, Marco Neumann wrote:
is TDB2 going to replace TDB or is TDB2 a new cluster product?
Whatever people (users, developers) want. Migrating Dbs is not as easy
as ungrading code. Running oaj.tdb and oaj.tdb2 side by side
(TDB2 is itself 7 maven modules ATM - some can be combined as they are
small and just "a good idea at the time").
TDB2 is not the cluster (that's Lizard). Mantis started as the
separation out of the low level code needed for Lizard. Initially
validation of the reworking of transaction and datastructures, a little
extra work has made it as viable as "TDB2"
Andy
(oaj = org.apache.jena)
Marco
On Mon, Jun 8, 2015 at 11:41 AM, Andy Seaborne <a...@apache.org> wrote:
Informational announcement: TDB2
TDB2 is a reworking of TDB based on updated implementations of transactions
and transactional data structures for project Lizard (a clustered SPARQL
store).
TDB2 has:
* Arbitrary scale write-once transactions
* New transaction system - can add other first class components.
(e.g. text indexes, cache tables)
* Models works across transaction boundaries
* Cleaner, simpler, more maintainable
TDB2 databases are not compatible with TDB databases. It uses a more
efficient encoding for RDF terms. [1]
Being a database, the new indexing and transaction code needs time to settle
to bring the maturity up. I'm using that tech in Lizard development.
Andy
TDB2 code:
https://github.com/afs/mantis/tree/master/tdb2
Lizard slides:
http://www.slideshare.net/andyseaborne/201411-apache-coneu-lizard
[1] An upgrade path using TDB1-style encoding is possible; it is an one-way
upgrade path and not reversible [2]. TDB2 adds control files for the
copy-on-write data structures that TDB1 does not understand.
[2] Actually, if the encoding is compatible, what will happen is that TDB1
will see the database at the time of the upgrade. Welcome to copy-on-write
immutable data structures.
