/**
* 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.io.hfile;
import java.io.IOException;
import java.util.NavigableMap;
import java.util.NavigableSet;
import java.util.concurrent.ConcurrentSkipListMap;
import java.util.concurrent.ConcurrentSkipListSet;
import org.apache.hadoop.hbase.classification.InterfaceAudience;
import org.apache.hadoop.conf.Configuration;
import org.codehaus.jackson.JsonGenerationException;
import org.codehaus.jackson.annotate.JsonIgnoreProperties;
import org.codehaus.jackson.map.JsonMappingException;
import org.codehaus.jackson.map.ObjectMapper;
import org.codehaus.jackson.map.SerializationConfig;
import com.yammer.metrics.core.Histogram;
import com.yammer.metrics.core.MetricsRegistry;
import com.yammer.metrics.stats.Snapshot;
/**
* Utilty for aggregating counts in CachedBlocks and toString/toJSON CachedBlocks and BlockCaches.
* No attempt has been made at making this thread safe.
*/
@InterfaceAudience.Private
public class BlockCacheUtil {
/**
* Needed making histograms.
*/
private static final MetricsRegistry METRICS = new MetricsRegistry();
/**
* Needed generating JSON.
*/
private static final ObjectMapper MAPPER = new ObjectMapper();
static {
MAPPER.configure(SerializationConfig.Feature.FAIL_ON_EMPTY_BEANS, false);
MAPPER.configure(SerializationConfig.Feature.FLUSH_AFTER_WRITE_VALUE, true);
MAPPER.configure(SerializationConfig.Feature.INDENT_OUTPUT, true);
}
/**
* @param cb
* @return The block content as String.
*/
public static String toString(final CachedBlock cb, final long now) {
return "filename=" + cb.getFilename() + ", " + toStringMinusFileName(cb, now);
}
/**
* Little data structure to hold counts for a file.
* Used doing a toJSON.
*/
static class CachedBlockCountsPerFile {
private int count = 0;
private long size = 0;
private int countData = 0;
private long sizeData = 0;
private final String filename;
CachedBlockCountsPerFile(final String filename) {
this.filename = filename;
}
public int getCount() {
return count;
}
public long getSize() {
return size;
}
public int getCountData() {
return countData;
}
public long getSizeData() {
return sizeData;
}
public String getFilename() {
return filename;
}
}
/**
* @param filename
* @param blocks
* @return A JSON String of <code>filename</code> and counts of <code>blocks</code>
* @throws JsonGenerationException
* @throws JsonMappingException
* @throws IOException
*/
public static String toJSON(final String filename, final NavigableSet<CachedBlock> blocks)
throws JsonGenerationException, JsonMappingException, IOException {
CachedBlockCountsPerFile counts = new CachedBlockCountsPerFile(filename);
for (CachedBlock cb: blocks) {
counts.count++;
counts.size += cb.getSize();
BlockType bt = cb.getBlockType();
if (bt != null && bt.isData()) {
counts.countData++;
counts.sizeData += cb.getSize();
}
}
return MAPPER.writeValueAsString(counts);
}
/**
* @param cbsbf
* @return JSON string of <code>cbsf</code> aggregated
* @throws JsonGenerationException
* @throws JsonMappingException
* @throws IOException
*/
public static String toJSON(final CachedBlocksByFile cbsbf)
throws JsonGenerationException, JsonMappingException, IOException {
return MAPPER.writeValueAsString(cbsbf);
}
/**
* @param bc
* @return JSON string of <code>bc</code> content.
* @throws JsonGenerationException
* @throws JsonMappingException
* @throws IOException
*/
public static String toJSON(final BlockCache bc)
throws JsonGenerationException, JsonMappingException, IOException {
return MAPPER.writeValueAsString(bc);
}
/**
* @param cb
* @return The block content of <code>bc</code> as a String minus the filename.
*/
public static String toStringMinusFileName(final CachedBlock cb, final long now) {
return "offset=" + cb.getOffset() +
", size=" + cb.getSize() +
", age=" + (now - cb.getCachedTime()) +
", type=" + cb.getBlockType() +
", priority=" + cb.getBlockPriority();
}
/**
* Get a {@link CachedBlocksByFile} instance and load it up by iterating content in
* {@link BlockCache}.
* @param conf Used to read configurations
* @param bc Block Cache to iterate.
* @return Laoded up instance of CachedBlocksByFile
*/
public static CachedBlocksByFile getLoadedCachedBlocksByFile(final Configuration conf,
final BlockCache bc) {
CachedBlocksByFile cbsbf = new CachedBlocksByFile(conf);
for (CachedBlock cb: bc) {
if (cbsbf.update(cb)) break;
}
return cbsbf;
}
/**
* Use one of these to keep a running account of cached blocks by file. Throw it away when done.
* This is different than metrics in that it is stats on current state of a cache.
* See getLoadedCachedBlocksByFile
*/
@JsonIgnoreProperties({"cachedBlockStatsByFile"})
public static class CachedBlocksByFile {
private int count;
private int dataBlockCount;
private long size;
private long dataSize;
private final long now = System.nanoTime();
private final int max;
public static final int DEFAULT_MAX = 100000;
CachedBlocksByFile() {
this(null);
}
CachedBlocksByFile(final Configuration c) {
this.max = c == null? DEFAULT_MAX:
c.getInt("hbase.ui.blockcache.by.file.max", DEFAULT_MAX);
}
/**
* Map by filename. use concurent utils because we want our Map and contained blocks sorted.
*/
private NavigableMap<String, NavigableSet<CachedBlock>> cachedBlockByFile =
new ConcurrentSkipListMap<String, NavigableSet<CachedBlock>>();
Histogram age = METRICS.newHistogram(CachedBlocksByFile.class, "age");
/**
* @param cb
* @return True if full.... if we won't be adding any more.
*/
public boolean update(final CachedBlock cb) {
if (isFull()) return true;
NavigableSet<CachedBlock> set = this.cachedBlockByFile.get(cb.getFilename());
if (set == null) {
set = new ConcurrentSkipListSet<CachedBlock>();
this.cachedBlockByFile.put(cb.getFilename(), set);
}
set.add(cb);
this.size += cb.getSize();
this.count++;
BlockType bt = cb.getBlockType();
if (bt != null && bt.isData()) {
this.dataBlockCount++;
this.dataSize += cb.getSize();
}
long age = this.now - cb.getCachedTime();
this.age.update(age);
return false;
}
/**
* @return True if full; i.e. there are more items in the cache but we only loaded up
* the maximum set in configuration <code>hbase.ui.blockcache.by.file.max</code>
* (Default: DEFAULT_MAX).
*/
public boolean isFull() {
return this.count >= this.max;
}
public NavigableMap<String, NavigableSet<CachedBlock>> getCachedBlockStatsByFile() {
return this.cachedBlockByFile;
}
/**
* @return count of blocks in the cache
*/
public int getCount() {
return count;
}
public int getDataCount() {
return dataBlockCount;
}
/**
* @return size of blocks in the cache
*/
public long getSize() {
return size;
}
/**
* @return Size of data.
*/
public long getDataSize() {
return dataSize;
}
public AgeSnapshot getAgeInCacheSnapshot() {
return new AgeSnapshot(this.age);
}
@Override
public String toString() {
Snapshot snapshot = this.age.getSnapshot();
return "count=" + count + ", dataBlockCount=" + this.dataBlockCount + ", size=" + size +
", dataSize=" + getDataSize() +
", mean age=" + this.age.mean() + ", stddev age=" + this.age.stdDev() +
", min age=" + this.age.min() + ", max age=" + this.age.max() +
", 95th percentile age=" + snapshot.get95thPercentile() +
", 99th percentile age=" + snapshot.get99thPercentile();
}
}
}