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SUMMARY:ROAR: Increasing the Flexibility and Performance of Distributed Se
 arch - Costin Raiciu (UCL)
DTSTART:20090319T160000Z
DTEND:20090319T170000Z
UID:TALK15761@talks.cam.ac.uk
CONTACT:Eiko Yoneki
DESCRIPTION:To be able to search the web\, modern search engines partition
  the web index over many machines\, each of which is consulted when answer
 ing a query. To increase query throughput\, replicas are added for each of
  these machines.\n\nThe key parameter of web search algorithms is the trad
 e-off between replication and partitioning: while increasing the partition
 ing level (which reduces the replication level) improves query completion 
 time since more servers handle the query\, increasing it indefinitely incu
 rs non-negligible startup costs for each sub-query. Further\, the optimal 
 point changes if we factor in costs related to storing and updating the da
 ta set\, or if the query rate changes. Finding the right operating point a
 nd adapting to it is crucial\, yet current algorithms assume a fixed trade
 -off\, with reconfiguration being slow and manual.\n\nIn this work\, we in
 troduce Rendezvous On a Ring (ROAR)\, a novel distributed algorithm that e
 nables on-the-fly re-configuring of the partitioning level while still ser
 vicing queries. In addition\, ROAR can add and remove servers without stop
 ping the system\, cope with temporary and permanent server failures\, and 
 provide very good load-balancing even in the face of servers having hetero
 geneous hardware capabilities.\n\nTo support these claims\, we present res
 ults from a 43-server testbed deployment of ROAR.\n\nBio: I am finishing m
 y PhD at UCL on "Making Privacy Preserving Search Practical"\, under the s
 upervision of Mark Handley and David Rosenblum. My thesis examines how we 
 can execute encrypted queries on encrypted data\, and shows how to paralel
 ize this search to make it applicable in practice. The latter technique is
  more general and has broader implications in the design of distributed\, 
 data-center based\, web search algorithms.\n\nI am also working with Mark 
 Handley and Damon Wischik of UCL (along with others in the Trilogy EU proj
 ect) on designing a multipath transport protocol and an appropriate conges
 tion control algorithm that achieves resource pooling.\n\nGenerally\, I am
  interested in distributed systems and networking\, as well as security\, 
 and I have worked on a few topics in these fields.\nMore info on my webpag
 e at: http://www.cs.ucl.ac.uk/staff/C.Raiciu/\n\n
LOCATION:FW26\, Computer Laboratory\, William Gates Builiding
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