/**
*
* 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.mob;
import java.io.IOException;
import java.io.InterruptedIOException;
import java.util.ArrayList;
import java.util.Date;
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.fs.Path;
import org.apache.hadoop.hbase.Cell;
import org.apache.hadoop.hbase.HConstants;
import org.apache.hadoop.hbase.KeyValue;
import org.apache.hadoop.hbase.KeyValueUtil;
import org.apache.hadoop.hbase.classification.InterfaceAudience;
import org.apache.hadoop.hbase.monitoring.MonitoredTask;
import org.apache.hadoop.hbase.regionserver.DefaultStoreFlusher;
import org.apache.hadoop.hbase.regionserver.HMobStore;
import org.apache.hadoop.hbase.regionserver.InternalScanner;
import org.apache.hadoop.hbase.regionserver.MemStoreSnapshot;
import org.apache.hadoop.hbase.regionserver.ScannerContext;
import org.apache.hadoop.hbase.regionserver.Store;
import org.apache.hadoop.hbase.regionserver.StoreFileWriter;
import org.apache.hadoop.hbase.regionserver.throttle.ThroughputControlUtil;
import org.apache.hadoop.hbase.regionserver.throttle.ThroughputController;
import org.apache.hadoop.hbase.util.Bytes;
import org.apache.hadoop.util.StringUtils;
/**
* An implementation of the StoreFlusher. It extends the DefaultStoreFlusher.
* If the store is not a mob store, the flusher flushes the MemStore the same with
* DefaultStoreFlusher,
* If the store is a mob store, the flusher flushes the MemStore into two places.
* One is the store files of HBase, the other is the mob files.
* <ol>
* <li>Cells that are not PUT type or have the delete mark will be directly flushed to HBase.</li>
* <li>If the size of a cell value is larger than a threshold, it'll be flushed
* to a mob file, another cell with the path of this file will be flushed to HBase.</li>
* <li>If the size of a cell value is smaller than or equal with a threshold, it'll be flushed to
* HBase directly.</li>
* </ol>
*
*/
@InterfaceAudience.Private
public class DefaultMobStoreFlusher extends DefaultStoreFlusher {
private static final Log LOG = LogFactory.getLog(DefaultMobStoreFlusher.class);
private final Object flushLock = new Object();
private long mobCellValueSizeThreshold = 0;
private Path targetPath;
private HMobStore mobStore;
public DefaultMobStoreFlusher(Configuration conf, Store store) throws IOException {
super(conf, store);
mobCellValueSizeThreshold = store.getFamily().getMobThreshold();
this.targetPath = MobUtils.getMobFamilyPath(conf, store.getTableName(),
store.getColumnFamilyName());
if (!this.store.getFileSystem().exists(targetPath)) {
this.store.getFileSystem().mkdirs(targetPath);
}
this.mobStore = (HMobStore) store;
}
/**
* Flushes the snapshot of the MemStore.
* If this store is not a mob store, flush the cells in the snapshot to store files of HBase.
* If the store is a mob one, the flusher flushes the MemStore into two places.
* One is the store files of HBase, the other is the mob files.
* <ol>
* <li>Cells that are not PUT type or have the delete mark will be directly flushed to
* HBase.</li>
* <li>If the size of a cell value is larger than a threshold, it'll be
* flushed to a mob file, another cell with the path of this file will be flushed to HBase.</li>
* <li>If the size of a cell value is smaller than or equal with a threshold, it'll be flushed to
* HBase directly.</li>
* </ol>
*/
@Override
public List<Path> flushSnapshot(MemStoreSnapshot snapshot, long cacheFlushId,
MonitoredTask status, ThroughputController throughputController) throws IOException {
ArrayList<Path> result = new ArrayList<>();
long cellsCount = snapshot.getCellsCount();
if (cellsCount == 0) return result; // don't flush if there are no entries
// Use a store scanner to find which rows to flush.
long smallestReadPoint = store.getSmallestReadPoint();
InternalScanner scanner = createScanner(snapshot.getScanners(), smallestReadPoint);
if (scanner == null) {
return result; // NULL scanner returned from coprocessor hooks means skip normal processing
}
StoreFileWriter writer;
try {
// TODO: We can fail in the below block before we complete adding this flush to
// list of store files. Add cleanup of anything put on filesystem if we fail.
synchronized (flushLock) {
status.setStatus("Flushing " + store + ": creating writer");
// Write the map out to the disk
writer = store.createWriterInTmp(cellsCount, store.getFamily().getCompressionType(),
false, true, true, false, snapshot.getTimeRangeTracker());
IOException e = null;
try {
// It's a mob store, flush the cells in a mob way. This is the difference of flushing
// between a normal and a mob store.
performMobFlush(snapshot, cacheFlushId, scanner, writer, status, throughputController);
} catch (IOException ioe) {
e = ioe;
// throw the exception out
throw ioe;
} finally {
if (e != null) {
writer.close();
} else {
finalizeWriter(writer, cacheFlushId, status);
}
}
}
} finally {
scanner.close();
}
LOG.info("Mob store is flushed, sequenceid=" + cacheFlushId + ", memsize="
+ StringUtils.TraditionalBinaryPrefix.long2String(snapshot.getDataSize(), "", 1) +
", hasBloomFilter=" + writer.hasGeneralBloom() +
", into tmp file " + writer.getPath());
result.add(writer.getPath());
return result;
}
/**
* Flushes the cells in the mob store.
* <ol>In the mob store, the cells with PUT type might have or have no mob tags.
* <li>If a cell does not have a mob tag, flushing the cell to different files depends
* on the value length. If the length is larger than a threshold, it's flushed to a
* mob file and the mob file is flushed to a store file in HBase. Otherwise, directly
* flush the cell to a store file in HBase.</li>
* <li>If a cell have a mob tag, its value is a mob file name, directly flush it
* to a store file in HBase.</li>
* </ol>
* @param snapshot Memstore snapshot.
* @param cacheFlushId Log cache flush sequence number.
* @param scanner The scanner of memstore snapshot.
* @param writer The store file writer.
* @param status Task that represents the flush operation and may be updated with status.
* @param throughputController A controller to avoid flush too fast.
* @throws IOException
*/
protected void performMobFlush(MemStoreSnapshot snapshot, long cacheFlushId,
InternalScanner scanner, StoreFileWriter writer, MonitoredTask status,
ThroughputController throughputController) throws IOException {
StoreFileWriter mobFileWriter = null;
int compactionKVMax = conf.getInt(HConstants.COMPACTION_KV_MAX,
HConstants.COMPACTION_KV_MAX_DEFAULT);
long mobCount = 0;
long mobSize = 0;
long time = snapshot.getTimeRangeTracker().getMax();
mobFileWriter = mobStore.createWriterInTmp(new Date(time), snapshot.getCellsCount(),
store.getFamily().getCompressionType(), store.getRegionInfo().getStartKey(), false);
// the target path is {tableName}/.mob/{cfName}/mobFiles
// the relative path is mobFiles
byte[] fileName = Bytes.toBytes(mobFileWriter.getPath().getName());
ScannerContext scannerContext =
ScannerContext.newBuilder().setBatchLimit(compactionKVMax).build();
List<Cell> cells = new ArrayList<>();
boolean hasMore;
String flushName = ThroughputControlUtil.getNameForThrottling(store, "flush");
boolean control = throughputController != null && !store.getRegionInfo().isSystemTable();
if (control) {
throughputController.start(flushName);
}
IOException ioe = null;
try {
do {
hasMore = scanner.next(cells, scannerContext);
if (!cells.isEmpty()) {
for (Cell c : cells) {
// If we know that this KV is going to be included always, then let us
// set its memstoreTS to 0. This will help us save space when writing to
// disk.
if (c.getValueLength() <= mobCellValueSizeThreshold || MobUtils.isMobReferenceCell(c)
|| c.getTypeByte() != KeyValue.Type.Put.getCode()) {
writer.append(c);
} else {
// append the original keyValue in the mob file.
mobFileWriter.append(c);
mobSize += c.getValueLength();
mobCount++;
// append the tags to the KeyValue.
// The key is same, the value is the filename of the mob file
Cell reference = MobUtils.createMobRefCell(c, fileName,
this.mobStore.getRefCellTags());
writer.append(reference);
}
int len = KeyValueUtil.length(c);
if (control) {
throughputController.control(flushName, len);
}
}
cells.clear();
}
} while (hasMore);
} catch (InterruptedException e) {
ioe = new InterruptedIOException(
"Interrupted while control throughput of flushing " + flushName);
throw ioe;
} catch (IOException e) {
ioe = e;
throw e;
} finally {
if (control) {
throughputController.finish(flushName);
}
if (ioe != null) {
mobFileWriter.close();
}
}
if (mobCount > 0) {
// commit the mob file from temp folder to target folder.
// If the mob file is committed successfully but the store file is not,
// the committed mob file will be handled by the sweep tool as an unused
// file.
status.setStatus("Flushing mob file " + store + ": appending metadata");
mobFileWriter.appendMetadata(cacheFlushId, false, mobCount);
status.setStatus("Flushing mob file " + store + ": closing flushed file");
mobFileWriter.close();
mobStore.commitFile(mobFileWriter.getPath(), targetPath);
mobStore.updateMobFlushCount();
mobStore.updateMobFlushedCellsCount(mobCount);
mobStore.updateMobFlushedCellsSize(mobSize);
} else {
try {
status.setStatus("Flushing mob file " + store + ": no mob cells, closing flushed file");
mobFileWriter.close();
// If the mob file is empty, delete it instead of committing.
store.getFileSystem().delete(mobFileWriter.getPath(), true);
} catch (IOException e) {
LOG.error("Failed to delete the temp mob file", e);
}
}
}
}