Oracle has announced the availability of the Enterprise Edition of the NoSQL database, highlighted at the recent Oracle OpenWorld. We’re still waiting for the download links for its open source community edition sibling.
Oracle revealed details of its NoSQL database at OpenWorld, showing delegates how the software can be used to manage large amounts of unstructured data, and how it fits as part of Oracle’s Big Data Appliance system. Data in Oracle NoSQL databases is distributed among many storage nodes, and is also split into multiple partitions that are then distributed across the storage nodes. Each partition has a master and several copies. When a data update is received, it is sent to the master copy, then propagated to the other copies.
One key difference between Oracle’s techniques for managing big data and those of other vendors is how consistency is handled. One of the problems about most big data management software is that speed is achieved by allowing different copies of the data to exist that may change when the database is eventually reconciled. Oracle gives database administrators the choice of how to trade off the speed that inconsistency offers against having consistent data but slower performance.
When you write a query requesting data from an Oracle NoSQL database, you’ll be able to specify that it should return the data in the master copy for consistency, or the closest (and therefore fastest) copy. If the administrator has specified absolute consistency, the system will update all the copies of the data before any data is returned to a user. There are also options for majority consistency and single copy consistency. Single copy consistency just gets the quickest copy with no checks on whether it’s been reconciled; majority consistency will accept the master version even if the system shows that some reconciliation is necessary to bring some outlying copies into line.
Oracle NoSQL Database (whitepaper)
Enterprise Edition of Oracle NoSQL (Download link)
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