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Approximate range selection queries in P2P systems. Abhishek Gupta, Divyakant Agrawal, Amer El Abbadi CIDR 03. The main Idea. Using “Locality Sensitive Hashing” to hash data, for similar data will hash to similar identifier. Built upon Chord Represent data in the form of relational objects.
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Approximate range selection queries in P2P systems Abhishek Gupta, Divyakant Agrawal, Amer El Abbadi CIDR 03
The main Idea • Using “Locality Sensitive Hashing” to hash data, for similar data will hash to similar identifier. • Built upon Chord • Represent data in the form of relational objects.
Locality sensitive hashing • Similar ranges are hashed to the same peer with high probability • A family of hash functions H is said to be locality preserving if for all h belongs to H we have: • Where
Min-wise independent permutation • A domain D, a random permutation π of D, a range set Q in D. the hash function is And satisfy this property
System architecture • Peer IP → [SHA-1] → NodeID • Data → [LSH] → DataID • Are both 32-bit identifier • Data was assigned to node if nodeID is min{ N | N is the set of node with NodeID >= DataID } • Query Routing • On the Ring of Chord
Conclusion • An architecutre for a relational data sharing P2P • A hashing based mechanism to locate data • Future work • Query on multiple attribute