An Object-Based Approach for E
ffective XML Data Storage

XML data storage is a critical issue due to the socalled IObottleneck problem emerged in nowdays computer systems This paperpresents an ob jectbased XML data representation model towards eective XML data placement The proposed representation of XML docu ments is analysed in a twolevel scheme the external level is based onthe structure of a browsing graph whereas the internal level is supportedby a treelike structure The main contribution of the paper is that it exploits the ob ject data model in order to consider XML data dependenciesaccess frequencies and constraints A simulation model has been developed in order to evaluate dierent XML data placement strategies andthe impact of the proposed representation model in the overall storageprocess XML data placement is applied on a tertiary storage subsystemby either constructive or iterative placement techniques Three popularpolicies the Organpipethe Camel and the Simulated Annealing algorithmshave been considered and experiments have been carried out onsynthetic workloads of XML data sets The need of applying an XMLdata storage policy is apparent as indicated by the resulted improve ments in seek and service times The Simulated Annealing approach hasbeen proven to outperform the other XML data placement strategies.