/**
* Licensed to the Apache Software Foundation (ASF) under one
* or more contributor license agreements. See the NOTICE file
* distributed with this work for additional information
* regarding copyright ownership. The ASF licenses this file
* to you under the Apache License, Version 2.0 (the
* "License"); you may not use this file except in compliance
* with the License. You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package org.apache.hadoop.hbase.client.metrics;
import com.google.common.collect.ImmutableMap;
import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;
import org.apache.hadoop.classification.InterfaceAudience;
import org.apache.hadoop.classification.InterfaceStability;
import java.util.HashMap;
import java.util.Map;
import java.util.concurrent.atomic.AtomicLong;
/**
* Provides client-side metrics related to scan operations
* The data can be passed to mapreduce framework or other systems.
* We use atomic longs so that one thread can increment,
* while another atomically resets to zero after the values are reported
* to hadoop's counters.
*
* Some of these metrics are general for any client operation such as put
* However, there is no need for this. So they are defined under scan operation
* for now.
*/
@InterfaceAudience.Public
@InterfaceStability.Evolving
public class ScanMetrics {
private static final Log LOG = LogFactory.getLog(ScanMetrics.class);
/**
* Hash to hold the String -> Atomic Long mappings.
*/
private final Map<String, AtomicLong> counters = new HashMap<String, AtomicLong>();
// AtomicLongs to hold the metrics values. These are all updated through ClientScanner and
// ScannerCallable. They are atomic longs so that atomic getAndSet can be used to reset the
// values after progress is passed to hadoop's counters.
/**
* number of RPC calls
*/
public final AtomicLong countOfRPCcalls = createCounter("RPC_CALLS");
/**
* number of remote RPC calls
*/
public final AtomicLong countOfRemoteRPCcalls = createCounter("REMOTE_RPC_CALLS");
/**
* sum of milliseconds between sequential next calls
*/
public final AtomicLong sumOfMillisSecBetweenNexts = createCounter("MILLIS_BETWEEN_NEXTS");
/**
* number of NotServingRegionException caught
*/
public final AtomicLong countOfNSRE = createCounter("NOT_SERVING_REGION_EXCEPTION");
/**
* number of bytes in Result objects from region servers
*/
public final AtomicLong countOfBytesInResults = createCounter("BYTES_IN_RESULTS");
/**
* number of bytes in Result objects from remote region servers
*/
public final AtomicLong countOfBytesInRemoteResults = createCounter("BYTES_IN_REMOTE_RESULTS");
/**
* number of regions
*/
public final AtomicLong countOfRegions = createCounter("REGIONS_SCANNED");
/**
* number of RPC retries
*/
public final AtomicLong countOfRPCRetries = createCounter("RPC_RETRIES");
/**
* number of remote RPC retries
*/
public final AtomicLong countOfRemoteRPCRetries = createCounter("REMOTE_RPC_RETRIES");
/**
* constructor
*/
public ScanMetrics() {
}
private AtomicLong createCounter(String counterName) {
AtomicLong c = new AtomicLong(0);
counters.put(counterName, c);
return c;
}
public void setCounter(String counterName, long value) {
AtomicLong c = this.counters.get(counterName);
if (c != null) {
c.set(value);
}
}
/**
* Get all of the values since the last time this function was called.
*
* Calling this function will reset all AtomicLongs in the instance back to 0.
*
* @return A Map of String -> Long for metrics
*/
public Map<String, Long> getMetricsMap() {
//Create a builder
ImmutableMap.Builder<String, Long> builder = ImmutableMap.builder();
//For every entry add the value and reset the AtomicLong back to zero
for (Map.Entry<String, AtomicLong> e : this.counters.entrySet()) {
builder.put(e.getKey(), e.getValue().getAndSet(0));
}
//Build the immutable map so that people can't mess around with it.
return builder.build();
}
}