add support for Hadoop Counters via job.setCounterAggregatorClass
The PregelixJob.setCounterAggregatorClass sets up a (user-specified)
global aggregator and an iterationComplete hook to save Counter values.
The user-specified Counter-based aggregator (must extend
HadoopCountersAggregator) is saved to HDFS in each iteration and should
be restart/snapshot-aware.
The usage for setting up counters is to make a call to
job.setCounterAggregatorClass. After job completion, the Counters may
be retrieved from HDFS using BspUtils.getCounters(job).
Note that there is currently only one spot for iterationComplete hooks
and this behavior occupies it.
9 files changed