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On Thu, Mar 24, 2016 at 11:11 PM, <dev-reject-1458828684.20517.ddaablpdbjjphejck...@hama.apache.org> wrote: > > To approve: > dev-accept-1458828684.20517.ddaablpdbjjphejck...@hama.apache.org > To reject: > dev-reject-1458828684.20517.ddaablpdbjjphejck...@hama.apache.org > To give a reason to reject: > %%% Start comment > %%% End comment > > > > ---------- Forwarded message ---------- > From: "刘强" <edward2...@qq.com> > To: dev <dev@hama.apache.org> > Cc: > Date: Thu, 24 Mar 2016 22:10:55 +0800 > Subject: About concurrency loading problem in GraphJobRunner.java in > HamaV0.7.1 > > Dear developers, > > I've got problem: > 16/03/24 20:30:53 INFO graph.GraphJobRunner: Total time spent for loading > vertices: 3447 ms > 16/03/24 20:30:53 INFO graph.GraphJobRunner: Total time spent for > broadcasting global vertex count: 789 ms > 16/03/24 20:30:54 INFO graph.GraphJobRunner: Total time spent for initial > superstep: 787 ms > 16/03/24 20:30:55 INFO graph.GraphJobRunner: Total time spent for > broadcasting aggregation values: 108 ms > 16/03/24 20:30:55 ERROR bsp.BSPTask: Error running bsp setup and bsp function. > java.lang.NullPointerException > at > org.apache.hama.util.UnsafeByteArrayInputStream.<init>(UnsafeByteArrayInputStream.java:63) > at org.apache.hama.util.WritableUtils.unsafeDeserialize(WritableUtils.java:63) > at org.apache.hama.graph.MapVerticesInfo.get(MapVerticesInfo.java:101) > at > org.apache.hama.graph.GraphJobRunner$ComputeRunnable.<init>(GraphJobRunner.java:367) > at org.apache.hama.graph.GraphJobRunner.doSuperstep(GraphJobRunner.java:277) > at org.apache.hama.graph.GraphJobRunner.bsp(GraphJobRunner.java:187) > at org.apache.hama.bsp.BSPTask.runBSP(BSPTask.java:171) > at org.apache.hama.bsp.BSPTask.run(BSPTask.java:144) > at org.apache.hama.bsp.GroomServer$BSPPeerChild.main(GroomServer.java:1255) > > I add some vertices print information both in loading from local vertices and > transferring vertices in partition phase (just print the vertex information. > vertex.toString()... ). Then its OK. > > I found that the above exception was because that while processing messages > in superstep, some vertices missed can cannot get from ConcurrentHashMap you > used in the MapVerticesInfo.java. > > This may be because that the loadVertices() funtion has some concurrency > problem. Too many threads are started and sometimes that the loaded funtion > may miss some vertices and I doubt its the problem of ConcurrencyHashMap. > > Can you tell me the reason why its caused? For I'm not quite sure. > > Thanks very much! > Yours , QiangLiu ! > > > > > > -- Best Regards, Edward J. Yoon
