Advances in Spatial and Temporal Databases

Volume 6849 of the series Lecture Notes in Computer Science pp 186-204

Thread-Level Parallel Indexing of Update Intensive Moving-Object Workloads

  • Darius ŠidlauskasAffiliated withAalborg University
  • , Kenneth A. RossAffiliated withColumbia University
  • , Christian S. JensenAffiliated withAarhus University
  • , Simonas ŠaltenisAffiliated withAalborg University

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Modern processors consist of multiple cores that each support parallel processing by multiple physical threads, and they offer ample main-memory storage. This paper studies the use of such processors for the processing of update-intensive moving-object workloads that contain very frequent updates as well as contain queries.

The non-trivial challenge addressed is that of avoiding contention between long-running queries and frequent updates. Specifically, the paper proposes a grid-based indexing technique. A static grid indexes a near up-to-date snapshot of the data to support queries, while a live grid supports updates. An efficient cloning technique that exploits the memcpy system call is used to maintain the static grid.

An empirical study conducted with three modern processors finds that very frequent cloning, on the order of tens of milliseconds, is feasible, that the proposal scales linearly with the number of hardware threads, and that it significantly outperforms the previous state-of-the-art approach in terms of update throughput and query freshness.