I released HBase 0.94.0 on May 15, 2012. This was the 4th release candidate.
0.94 is mostly a performance release with a lot of contributions from Facebook.
As mentioned in the release announcement these are some notable improvements:
- HBASE-5010 - Filter HFiles based on TTL
- HBASE-4465 - Lazy-seek optimization for StoreFile scanners
- HBASE-4469 - Avoid top row seek by looking up ROWCOL bloomfilter
- HBASE-4532 - Avoid top row seek by dedicated bloom filter for delete family bloom filter
- HBASE-5074 - support checksums in HBase block cache
Of course there are some new features as well.
- Jonathan Hsieh's HBASE-5128 - [uber hbck] Online automated repair of table integrity and region consistency problems
- Jon Gray's HBASE-4460 - Support running an embedded ThriftServer within a RegionServer
- HBASE-3584 - Allow atomic put/delete in one call
- HBASE-4102 - atomicAppend: A put that appends to the latest version of a cell
- HBASE-4536 - Allow CF to retain deleted rows
- HBASE-5229 - Provide basic building blocks for "multi-row" local transactions.
I expect 0.94.x to be used for a while until the "singularity" (0.96) stabilizes into HBase 1.0.
Update Wednesday, May 30th, 2012:
HBase can be downloaded from here: http://www.apache.org/dyn/closer.cgi/hbase/
The list of features and bug fixes is here.