Re: Too few memory segments provided exception

Posted by Shivani Ghatge on
URL: http://deprecated-apache-flink-user-mailing-list-archive.369.s1.nabble.com/Too-few-memory-segments-provided-exception-tp2176p2191.html

But it will need to build BloomFilters for each vertex for each edge so idk how efficient that would be.

On Mon, Jul 20, 2015 at 4:02 PM, Shivani Ghatge <[hidden email]> wrote:
Hello Vasia,

I will adapt the exact method for BloomFilter. (I think it can be done. Sorry. My mistake). 


On Mon, Jul 20, 2015 at 3:45 PM, Shivani Ghatge <[hidden email]> wrote:
Also the example of Jaccard that you had linked me to used VertexCentric configuration which I understand is because that api only uses VertexCentricIteration for all the operations? But I think that is the best way in order to know what neighbors belong to the BloomFilter?

On Mon, Jul 20, 2015 at 3:43 PM, Shivani Ghatge <[hidden email]> wrote:
Hello Vasia,

As I had mentioned before, I need a BloomFilter as well as a HashSet for the approximation to work. In the exact solution I am getting two HashSets and comparing them. In approximate version, if we get two BloomFilters then we have no way to compare the neighborhood sets.

I thought we agreed that the BloomFilters are to be sent as messages to the vertices?

The exact version is passing all the tests.

On removing the final GroupReduce the program is working but I need it to add the Partial Adamic Adar edges weights.

On Mon, Jul 20, 2015 at 3:15 PM, Vasiliki Kalavri <[hidden email]> wrote:
Hi Shivani,

why are you using a vertex-centric iteration to compute the approximate Adamic-Adar?
It's not an iterative computation :) 

In fact, it should be as complex (in terms of operators) as the exact Adamic-Adar, only more efficient because of the different neighborhood representation. Are you having the same problem with the exact computation?

Cheers,
Vasia.

On 20 July 2015 at 14:41, Maximilian Michels <[hidden email]> wrote:
Hi Shivani,

The issue is that by the time the Hash Join is executed, the MutableHashTable cannot allocate enough memory segments. That means that your other operators are occupying them. It is fine that this also occurs on Travis because the workers there have limited memory as well.

Till suggested to change the memory fraction through the ExuectionEnvironment. Can you try that?

Cheers,
Max

On Mon, Jul 20, 2015 at 2:23 PM, Shivani Ghatge <[hidden email]> wrote:
Hello Maximilian,

Thanks for the suggestion. I will use it to check the program. But when I am creating a PR for the same implementation with a Test, I am getting the same error even on Travis build. So for that what would be the solution?

Here is my PR https://github.com/apache/flink/pull/923
And here is the Travis build status https://travis-ci.org/apache/flink/builds/71695078

Also on the IDE it is working fine in Collection execution mode.

Thanks and Regards,
Shivani

On Mon, Jul 20, 2015 at 2:14 PM, Maximilian Michels <[hidden email]> wrote:
Hi Shivani,

Flink doesn't have enough memory to perform a hash join. You need to provide Flink with more memory. You can either increase the "taskmanager.heap.mb" config variable or set "taskmanager.memory.fraction" to some value greater than 0.7 and smaller then 1.0. The first config variable allocates more overall memory for Flink; the latter changes the ratio between Flink managed memory (e.g. for hash join) and user memory (for you functions and Gelly's code).

If you run this inside an IDE, the memory is configured automatically and you don't have control over that at the moment. You could, however, start a local cluster (./bin/start-local) after you adjusted your flink-conf.yaml and run your programs against that configured cluster. You can do that either through your IDE using a RemoteEnvironment or by submitting the packaged JAR to the local cluster using the command-line tool (./bin/flink).

Hope that helps.

Cheers,
Max

On Mon, Jul 20, 2015 at 2:04 PM, Shivani Ghatge <[hidden email]> wrote:
Hello,
 I am working on a problem which implements Adamic Adar Algorithm using Gelly.
I am running into this exception for all the Joins (including the one that are part of the reduceOnNeighbors function)

Too few memory segments provided. Hash Join needs at least 33 memory segments.


The problem persists even when I comment out some of the joins.

Even after using edg = edg.join(graph.getEdges(), JoinOperatorBase.JoinHint.BROADCAST_HASH_SECOND).where(0,1).equalTo(0,1).with(new JoinEdge());

as suggested by @AndraLungu the problem persists.

The code is


DataSet<Tuple2<Long, Long>> degrees = graph.getDegrees();

        //get neighbors of each vertex in the HashSet for it's value
        computedNeighbors = graph.reduceOnNeighbors(new GatherNeighbors(), EdgeDirection.ALL);
       
        //get vertices with updated values for the final Graph which will be used to get Adamic Edges
        Vertices = computedNeighbors.join(degrees, JoinOperatorBase.JoinHint.BROADCAST_HASH_FIRST).where(0).equalTo(0).with(new JoinNeighborDegrees());

        Graph<Long, Tuple3<Double, HashSet<Long>, List<Tuple3<Long, Long, Double>>>, Double> updatedGraph =
                Graph.fromDataSet(Vertices, edges, env);
       
        //configure Vertex Centric Iteration
        VertexCentricConfiguration parameters = new VertexCentricConfiguration();

        parameters.setName("Find Adamic Adar Edge Weights");

        parameters.setDirection(EdgeDirection.ALL);
       
        //run Vertex Centric Iteration to get the Adamic Adar Edges into the vertex Value
        updatedGraph = updatedGraph.runVertexCentricIteration(new GetAdamicAdarEdges<Long>(), new NeighborsMessenger<Long>(), 1, parameters);
       
        //Extract Vertices of the updated graph
        DataSet<Vertex<Long, Tuple3<Double, HashSet<Long>, List<Tuple3<Long, Long, Double>>>>> vertices = updatedGraph.getVertices();
       
        //Extract the list of Edges from the vertex values
        DataSet<Tuple3<Long, Long, Double>> edg = vertices.flatMap(new GetAdamicList());
       
        //Partial weights for the edges are added
        edg = edg.groupBy(0,1).reduce(new AdamGroup());

        //Graph is updated with the Adamic Adar Edges
        edg = edg.join(graph.getEdges(), JoinOperatorBase.JoinHint.BROADCAST_HASH_SECOND).where(0,1).equalTo(0,1).with(new JoinEdge());

Any idea how I could tackle this Exception?