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Subscription Partitioning and Routing in Content-based Publish/Subscribe Networks. Yi-Min Wang, Lili Qiu, Dimitris Achlioptas, Gautam Das, Paul Larson, and Helen J. Wang Microsoft Research DISC 2002 Toulouse, France. Motivation. Network Architecture. Subscription Partitioning.
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Subscription Partitioning and Routing in Content-based Publish/Subscribe Networks Yi-Min Wang, Lili Qiu, Dimitris Achlioptas, Gautam Das, Paul Larson, and Helen J. Wang Microsoft Research DISC 2002 Toulouse, France
Equality Predicates • Hash predicates to get uniform distribution • Treat the hashed domain as the event space • Use Event Space Partitioning • Subscription is a point; does not intersect multiple sub-spaces • Use over-partitioning for better load balancing • Use offline greedy algorithm to assign buckets to servers for load balancing • Use indirection table to dynamically map buckets to servers for load re-balancing • Use Bloom filters to further reduce traffic • Fast detection of true negatives at the expense of (very low) false-positive rate
Summary of simulation results • Actual MSN Money log: 1.48M subscription with 0.29M unique filters over 21,741 stock symbols • Zipf-like distribution: MSFT 58,518, CSCO 43,073, $COMPX 32,485, $INDU 31,111, INTC 25,,903, $INX 22,519, AOL 21,836, LU 20,056, ORCL 18,038, DELL 16,211, etc.
Simulate 100M new subscriptions from 43,734 symbols • Scaled-up Zipf-like distribution • Perturbation and permutation • Uniform distribution • 50 servers with over-partitioning ratio = 10 • Without load re-balancing • Load imbalance (max/min) ranged from 1.41 to 6.66 (Uniform case) • With imbalance threshold of 2.0 • Re-balancing was triggered only 5 times, each time involving re-assignment of up to 3 buckets and migration of up to 0.7% subscriptions.