/**
* Constructor.
*
* @param conf Configuration
*/
public DiskBackedPartitionStore(ImmutableClassesGiraphConfiguration<I, V, E, M> conf) {
this.conf = conf;
// We must be able to hold at least one partition in memory
maxInMemoryPartitions =
Math.max(
1,
conf.getInt(
GiraphConfiguration.MAX_PARTITIONS_IN_MEMORY,
GiraphConfiguration.MAX_PARTITIONS_IN_MEMORY_DEFAULT));
basePath =
conf.get("mapred.job.id", "Unknown Job")
+ conf.get(
GiraphConfiguration.PARTITIONS_DIRECTORY,
GiraphConfiguration.PARTITIONS_DIRECTORY_DEFAULT);
}
/**
* Read a partition from disk.
*
* @param partitionId Id of the partition to read
* @return The partition object
* @throws IOException
*/
private Partition<I, V, E, M> readPartition(Integer partitionId) throws IOException {
Partition<I, V, E, M> partition = new Partition<I, V, E, M>(conf, partitionId);
File file = new File(getPartitionPath(partitionId));
DataInputStream inputStream =
new DataInputStream(new BufferedInputStream(new FileInputStream(file)));
int numVertices = onDiskPartitions.get(partitionId);
for (int i = 0; i < numVertices; ++i) {
Vertex<I, V, E, M> vertex = conf.createVertex();
vertex.readFields(inputStream);
partition.putVertex(vertex);
}
inputStream.close();
file.delete();
return partition;
}