/**
* 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.regionserver;
import java.io.IOException;
import java.lang.management.ManagementFactory;
import java.lang.management.RuntimeMXBean;
import java.util.ArrayList;
import java.util.List;
import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;
import org.apache.hadoop.conf.Configuration;
import org.apache.hadoop.hbase.Cell;
import org.apache.hadoop.hbase.CellComparator;
import org.apache.hadoop.hbase.HBaseConfiguration;
import org.apache.hadoop.hbase.HConstants;
import org.apache.hadoop.hbase.KeyValue;
import org.apache.hadoop.hbase.classification.InterfaceAudience;
import org.apache.hadoop.hbase.util.Bytes;
import org.apache.hadoop.hbase.util.ClassSize;
import org.apache.hadoop.hbase.util.EnvironmentEdgeManager;
/**
* The MemStore holds in-memory modifications to the Store. Modifications
* are {@link Cell}s. When asked to flush, current memstore is moved
* to snapshot and is cleared. We continue to serve edits out of new memstore
* and backing snapshot until flusher reports in that the flush succeeded. At
* this point we let the snapshot go.
* <p>
* The MemStore functions should not be called in parallel. Callers should hold
* write and read locks. This is done in {@link HStore}.
* </p>
*
* TODO: Adjust size of the memstore when we remove items because they have
* been deleted.
* TODO: With new KVSLS, need to make sure we update HeapSize with difference
* in KV size.
*/
@InterfaceAudience.Private
public class DefaultMemStore extends AbstractMemStore {
private static final Log LOG = LogFactory.getLog(DefaultMemStore.class);
public final static long DEEP_OVERHEAD = ClassSize.align(AbstractMemStore.DEEP_OVERHEAD);
public final static long FIXED_OVERHEAD = ClassSize.align(AbstractMemStore.FIXED_OVERHEAD);
/**
* Default constructor. Used for tests.
*/
public DefaultMemStore() {
this(HBaseConfiguration.create(), CellComparator.COMPARATOR);
}
/**
* Constructor.
* @param c Comparator
*/
public DefaultMemStore(final Configuration conf, final CellComparator c) {
super(conf, c);
}
/**
* Creates a snapshot of the current memstore.
* Snapshot must be cleared by call to {@link #clearSnapshot(long)}
*/
@Override
public MemStoreSnapshot snapshot() {
// If snapshot currently has entries, then flusher failed or didn't call
// cleanup. Log a warning.
if (!this.snapshot.isEmpty()) {
LOG.warn("Snapshot called again without clearing previous. " +
"Doing nothing. Another ongoing flush or did we fail last attempt?");
} else {
this.snapshotId = EnvironmentEdgeManager.currentTime();
if (!this.active.isEmpty()) {
ImmutableSegment immutableSegment = SegmentFactory.instance().
createImmutableSegment(this.active);
this.snapshot = immutableSegment;
resetActive();
}
}
return new MemStoreSnapshot(this.snapshotId, this.snapshot);
}
/**
* On flush, how much memory we will clear from the active cell set.
*
* @return size of data that is going to be flushed from active set
*/
@Override
public MemstoreSize getFlushableSize() {
MemstoreSize snapshotSize = getSnapshotSize();
return snapshotSize.getDataSize() > 0 ? snapshotSize
: new MemstoreSize(keySize(), heapSize());
}
@Override
protected long keySize() {
return this.active.keySize();
}
@Override
protected long heapSize() {
return this.active.heapSize();
}
@Override
/*
* Scanners are ordered from 0 (oldest) to newest in increasing order.
*/
public List<KeyValueScanner> getScanners(long readPt) throws IOException {
List<KeyValueScanner> list = new ArrayList<>();
long order = snapshot.getNumOfSegments();
order = addToScanners(active, readPt, order, list);
addToScanners(snapshot.getAllSegments(), readPt, order, list);
return list;
}
@Override
protected List<Segment> getSegments() throws IOException {
List<Segment> list = new ArrayList<>(2);
list.add(this.active);
list.add(this.snapshot);
return list;
}
/**
* @param cell Find the row that comes after this one. If null, we return the
* first.
* @return Next row or null if none found.
*/
Cell getNextRow(final Cell cell) {
return getLowest(
getNextRow(cell, this.active.getCellSet()),
getNextRow(cell, this.snapshot.getCellSet()));
}
@Override public void updateLowestUnflushedSequenceIdInWAL(boolean onlyIfMoreRecent) {
}
@Override
public MemstoreSize size() {
return new MemstoreSize(this.active.keySize(), this.active.heapSize());
}
/**
* Check whether anything need to be done based on the current active set size
* Nothing need to be done for the DefaultMemStore
*/
@Override
protected void checkActiveSize() {
return;
}
@Override
public long preFlushSeqIDEstimation() {
return HConstants.NO_SEQNUM;
}
@Override public boolean isSloppy() {
return false;
}
/**
* Code to help figure if our approximation of object heap sizes is close
* enough. See hbase-900. Fills memstores then waits so user can heap
* dump and bring up resultant hprof in something like jprofiler which
* allows you get 'deep size' on objects.
* @param args main args
*/
public static void main(String [] args) {
RuntimeMXBean runtime = ManagementFactory.getRuntimeMXBean();
LOG.info("vmName=" + runtime.getVmName() + ", vmVendor=" +
runtime.getVmVendor() + ", vmVersion=" + runtime.getVmVersion());
LOG.info("vmInputArguments=" + runtime.getInputArguments());
DefaultMemStore memstore1 = new DefaultMemStore();
// TODO: x32 vs x64
final int count = 10000;
byte [] fam = Bytes.toBytes("col");
byte [] qf = Bytes.toBytes("umn");
byte [] empty = new byte[0];
MemstoreSize memstoreSize = new MemstoreSize();
for (int i = 0; i < count; i++) {
// Give each its own ts
memstore1.add(new KeyValue(Bytes.toBytes(i), fam, qf, i, empty), memstoreSize);
}
LOG.info("memstore1 estimated size="
+ (memstoreSize.getDataSize() + memstoreSize.getHeapSize()));
for (int i = 0; i < count; i++) {
memstore1.add(new KeyValue(Bytes.toBytes(i), fam, qf, i, empty), memstoreSize);
}
LOG.info("memstore1 estimated size (2nd loading of same data)="
+ (memstoreSize.getDataSize() + memstoreSize.getHeapSize()));
// Make a variably sized memstore.
DefaultMemStore memstore2 = new DefaultMemStore();
memstoreSize = new MemstoreSize();
for (int i = 0; i < count; i++) {
memstore2.add(new KeyValue(Bytes.toBytes(i), fam, qf, i, new byte[i]), memstoreSize);
}
LOG.info("memstore2 estimated size="
+ (memstoreSize.getDataSize() + memstoreSize.getHeapSize()));
final int seconds = 30;
LOG.info("Waiting " + seconds + " seconds while heap dump is taken");
LOG.info("Exiting.");
}
}