HBase 0.94

In all the hectic leading up to HBaseCon, I forgot to blog about HBase 0.94.

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

among others. Many thanks to Mikhail Bautin and others at Facebook for all these improvements.

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

And then of course my pets (I blogged about these before):

• 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.

0.94 is binary compatible with 0.92. Server and client can be freely mixed between versions, it is even possible to mix servers of different version within the same cluster (for rolling upgrades).

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.