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Tried this with off-the-shelf radix tree that claims to be fast and cache optimized (Judy): with 2^20 nodes average lookup time of about 3300 cycles on an AMD64 and 524 cycles on a Core 2 Duo, allocated 15 MB of RAM during inserts

B-Trees

  • + Supports range queries on totally ordered keys
  • +/- Allows several records from the same table to be returned with a single request
    • Can give control over placement if they can take advantage of it for locality
  • May cause a server to become a hot spot
    • Is this anymore true than with hashing?
  • - Latency (at least as bad as DHT)

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Questions

  • How do we update the address mapping when a host fails?
    • Clients that detect the failed node initiate an update of the mapping
      • Where, to whom?

Locality

Effects

  • + Network traffic
  • + Latency for serial requests
  • + Performance isolation in multi-tenant environments
  • + Economy of metadata
    • For example, only access control information for data which resides on a host must be replicated to that host

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