This document discusses Omid, a system for providing efficient transaction management and incremental processing for HBase. Omid implements an optimistic concurrency control model called snapshot isolation without locking. It has a simple API based on Java Transaction API and HBase API. Omid's architecture involves a centralized server for transaction metadata coordination and replication of metadata to HBase clients. It uses BookKeeper for fault tolerance. An example application described is performing TF-IDF indexing of tweets incrementally using Omid transactions.