Hi Deepika, Omid provides Snapshot Isolation (SI), which is a well-known isolation guarantee in database systems such as Oracle. In short, each transaction reads from a consistent snapshot that does not include partial changes by concurrent (or failed) transactions. SI also prevents write-write conflicts between concurrent transactions. The overhead of Omid on HBase is negligible and does not require any changes into HBase, with the only exception of HBase garbage collection algorithm that is replaced via a coprocessor. hbase-trx, on the other hand, does not provide read snapshots and is not safe with client failures. You can find a more detailed comparison in the Omid wiki page: https://github.com/yahoo/omid/wiki
Cheers - Maysam Yabandeh On Mar 19, 2012, at 6:49 PM, Deepika Khera wrote: > Hi, > > I have some map reduce jobs that write to Hbase. I am trying to pick a > library that could provide transactional support for Hbase. I looked at > Omid and hbase-trx . > > Could you please provide me with a comparison between the two so I can > make the right choice. > Are there any other ways to do this? > > Thanks, > Deepika > > > >
