XML projection is one of the main adopted optimization techniques for reducing memory consumption in XQuery
in-memory engines. The main idea behind this technique is quite simple: given a query Q over an XML document D,
instead of evaluating Q on D, the query Q is evaluated on a smaller document D' obtained from D by pruning out,
at loading-time, parts of D that are unrelevant for Q. The actual queried document D' is a projection of the
original one, and is often much smaller than D due to the fact that queries tend to be quite selective in general.
While projection techniques have been extensively investigated for XML querying, we are not aware of
applications to XML updating.
The purpose of this work is to investigate a projection based optimization mechanism for XML updates.
ViP2P is a fully functional Java-based platform for the efficient, scalable management of XML documents
in structured peer-to-peer networks based on distributed hash table (DHT) indices. We exploit indices (or
materialized views) deployed in the P2P network independently by the peers, to answer an interesting dialect
of tree pattern queries. There is a query (and view) language, a rewriting algorithm, view definition
indexing strategies based on the DHT and much more...
You can find out more details about ViP2P by visiting the ViP2P website.