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twitter / cassovary

Cassovary is a simple big graph processing library for the JVM
http://twitter.com/cassovary
Apache License 2.0
1.05k stars 150 forks source link

Implement efficient dynamic graph for the case of concurrent reads an… #198

Closed plofgren closed 9 years ago

plofgren commented 9 years ago

…d single-threaded writes. @ashishgpersonal When you have time, could you code review this? Also, two questions:

  1. Currently addEdges does not check for duplicate edges, because e.g. if Obama gets a new in-neighbor I don't want to scan all his current in-neighbors, and I don't want the overhead of using hashMaps rather than arrays. I think duplicate edges should be rare enough for us to ignore for now--is that OK? It's not hard to add the check, it's just an efficiency question.
  2. I don't think it's easy to test race conditions without inserting artificial Thread.sleep calls. Could you look carefully at the append method in SemiSynchronizedIntArrayList and see if you think it's thread safe with concurrent readers?

Thanks

plofgren commented 9 years ago

(I meant to pull request this in to plofgren/cassovary first. Closing for now on twitter/cassovary.)