This following post was originally published via blog.apache.org; we republish it here for your convenience.
NOTE: This blog post describes how Apache HBase does concurrency control. This assumes knowledge of the HBase write path, which you can read more about in this other blog post.
Apache HBase provides a consistent and understandable data model to the user while still offering high performance.
One of the major features of the upcoming Apache HBase 0.96 release is improved support for compatibility and extensibility across different HBase versions. This includes support for the following:
- Upgrading with no downtime: support for a rolling upgrade across a single major version (e.g. 0.96 to 0.98). Because HBase has lacked this feature, moving to a new major version has required “lock step” upgrades: the entire cluster has to be shut down,