package com.twitter.elephantbird.pig.util;
import java.util.Map;
import com.google.common.collect.Maps;
import com.twitter.elephantbird.util.HadoopCompat;
import org.apache.hadoop.mapreduce.Counter;
import org.apache.pig.impl.util.Pair;
import org.apache.pig.tools.pigstats.PigStatusReporter;
/**
* A helper class to deal with Hadoop counters in Pig. They are stored within the singleton
* PigStatusReporter instance, but are null for some period of time at job startup, even after
* Pig has been invoked. This class buffers counters, trying each time to get a valid Reporter and flushing
* stored counters each time it does.
*/
public class PigCounterHelper {
private final Map<Pair<String, String>, Long> counterStringMap_ = Maps.newHashMap();
private final Map<Enum<?>, Long> counterEnumMap_ = Maps.newHashMap();
/**
* Mocks the Reporter.incrCounter, but adds buffering.
* See org.apache.hadoop.mapred.Reporter's incrCounter.
*/
public void incrCounter(String group, String counterName, long incr) {
PigStatusReporter reporter = PigStatusReporter.getInstance();
if (reporter != null) { // common case
Counter counter = reporter.getCounter(group, counterName);
if (counter != null) {
HadoopCompat.incrementCounter(counter, incr);
if (counterStringMap_.size() > 0) {
for (Map.Entry<Pair<String, String>, Long> entry : counterStringMap_.entrySet()) {
HadoopCompat.incrementCounter(
reporter.getCounter(entry.getKey().first, entry.getKey().second),
entry.getValue());
}
counterStringMap_.clear();
}
return;
}
}
// In the case when reporter is not available, or we can't get the Counter,
// store in the local map.
Pair<String, String> key = new Pair<String, String>(group, counterName);
Long currentValue = counterStringMap_.get(key);
counterStringMap_.put(key, (currentValue == null ? 0 : currentValue) + incr);
}
/**
* Mocks the Reporter.incrCounter, but adds buffering.
* See org.apache.hadoop.mapred.Reporter's incrCounter.
*/
public void incrCounter(Enum<?> key, long incr) {
PigStatusReporter reporter = PigStatusReporter.getInstance();
if (reporter != null && reporter.getCounter(key) != null) {
HadoopCompat.incrementCounter(reporter.getCounter(key), incr);
if (counterEnumMap_.size() > 0) {
for (Map.Entry<Enum<?>, Long> entry : counterEnumMap_.entrySet()) {
HadoopCompat.incrementCounter(
reporter.getCounter(entry.getKey()), entry.getValue());
}
counterEnumMap_.clear();
}
} else { // buffer the increments
Long currentValue = counterEnumMap_.get(key);
counterEnumMap_.put(key, (currentValue == null ? 0 : currentValue) + incr);
}
}
}