/**
* 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.replication.regionserver;
import java.io.IOException;
import java.io.InterruptedIOException;
import java.util.ArrayList;
import java.util.List;
import java.util.Map;
import java.util.concurrent.Callable;
import java.util.concurrent.ExecutionException;
import java.util.concurrent.ExecutorService;
import java.util.concurrent.Future;
import java.util.concurrent.LinkedBlockingQueue;
import java.util.concurrent.ThreadPoolExecutor;
import java.util.concurrent.TimeUnit;
import java.util.concurrent.atomic.AtomicLong;
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.CellScanner;
import org.apache.hadoop.hbase.CellUtil;
import org.apache.hadoop.hbase.HBaseConfiguration;
import org.apache.hadoop.hbase.HBaseIOException;
import org.apache.hadoop.hbase.HConstants;
import org.apache.hadoop.hbase.HRegionInfo;
import org.apache.hadoop.hbase.HRegionLocation;
import org.apache.hadoop.hbase.HTableDescriptor;
import org.apache.hadoop.hbase.RegionLocations;
import org.apache.hadoop.hbase.TableDescriptors;
import org.apache.hadoop.hbase.TableName;
import org.apache.hadoop.hbase.TableNotFoundException;
import org.apache.hadoop.hbase.classification.InterfaceAudience;
import org.apache.hadoop.hbase.client.ClusterConnection;
import org.apache.hadoop.hbase.client.ConnectionFactory;
import org.apache.hadoop.hbase.client.RegionAdminServiceCallable;
import org.apache.hadoop.hbase.client.RegionReplicaUtil;
import org.apache.hadoop.hbase.client.RetryingCallable;
import org.apache.hadoop.hbase.client.RpcRetryingCallerFactory;
import org.apache.hadoop.hbase.ipc.HBaseRpcController;
import org.apache.hadoop.hbase.ipc.RpcControllerFactory;
import org.apache.hadoop.hbase.protobuf.ReplicationProtbufUtil;
import org.apache.hadoop.hbase.shaded.protobuf.generated.AdminProtos;
import org.apache.hadoop.hbase.shaded.protobuf.generated.AdminProtos.ReplicateWALEntryResponse;
import org.apache.hadoop.hbase.replication.BaseWALEntryFilter;
import org.apache.hadoop.hbase.replication.ChainWALEntryFilter;
import org.apache.hadoop.hbase.replication.HBaseReplicationEndpoint;
import org.apache.hadoop.hbase.replication.WALEntryFilter;
import org.apache.hadoop.hbase.util.Bytes;
import org.apache.hadoop.hbase.util.Pair;
import org.apache.hadoop.hbase.util.Threads;
import org.apache.hadoop.hbase.wal.WAL.Entry;
import org.apache.hadoop.hbase.wal.WALSplitter.EntryBuffers;
import org.apache.hadoop.hbase.wal.WALSplitter.OutputSink;
import org.apache.hadoop.hbase.wal.WALSplitter.PipelineController;
import org.apache.hadoop.hbase.wal.WALSplitter.RegionEntryBuffer;
import org.apache.hadoop.hbase.wal.WALSplitter.SinkWriter;
import org.apache.hadoop.util.StringUtils;
import com.google.common.cache.Cache;
import com.google.common.cache.CacheBuilder;
import com.google.common.collect.Lists;
/**
* A {@link org.apache.hadoop.hbase.replication.ReplicationEndpoint} endpoint
* which receives the WAL edits from the WAL, and sends the edits to replicas
* of regions.
*/
@InterfaceAudience.Private
public class RegionReplicaReplicationEndpoint extends HBaseReplicationEndpoint {
private static final Log LOG = LogFactory.getLog(RegionReplicaReplicationEndpoint.class);
// Can be configured differently than hbase.client.retries.number
private static String CLIENT_RETRIES_NUMBER
= "hbase.region.replica.replication.client.retries.number";
private Configuration conf;
private ClusterConnection connection;
private TableDescriptors tableDescriptors;
// Reuse WALSplitter constructs as a WAL pipe
private PipelineController controller;
private RegionReplicaOutputSink outputSink;
private EntryBuffers entryBuffers;
// Number of writer threads
private int numWriterThreads;
private int operationTimeout;
private ExecutorService pool;
/**
* Skips the entries which has original seqId. Only entries persisted via distributed log replay
* have their original seq Id fields set.
*/
private static class SkipReplayedEditsFilter extends BaseWALEntryFilter {
@Override
public Entry filter(Entry entry) {
// if orig seq id is set, skip replaying the entry
if (entry.getKey().getOrigLogSeqNum() > 0) {
return null;
}
return entry;
}
}
@Override
public WALEntryFilter getWALEntryfilter() {
WALEntryFilter superFilter = super.getWALEntryfilter();
WALEntryFilter skipReplayedEditsFilter = getSkipReplayedEditsFilter();
if (superFilter == null) {
return skipReplayedEditsFilter;
}
if (skipReplayedEditsFilter == null) {
return superFilter;
}
ArrayList<WALEntryFilter> filters = Lists.newArrayList();
filters.add(superFilter);
filters.add(skipReplayedEditsFilter);
return new ChainWALEntryFilter(filters);
}
protected WALEntryFilter getSkipReplayedEditsFilter() {
return new SkipReplayedEditsFilter();
}
@Override
public void init(Context context) throws IOException {
super.init(context);
this.conf = HBaseConfiguration.create(context.getConfiguration());
this.tableDescriptors = context.getTableDescriptors();
// HRS multiplies client retries by 10 globally for meta operations, but we do not want this.
// We are resetting it here because we want default number of retries (35) rather than 10 times
// that which makes very long retries for disabled tables etc.
int defaultNumRetries = conf.getInt(HConstants.HBASE_CLIENT_RETRIES_NUMBER,
HConstants.DEFAULT_HBASE_CLIENT_RETRIES_NUMBER);
if (defaultNumRetries > 10) {
int mult = conf.getInt("hbase.client.serverside.retries.multiplier", 10);
defaultNumRetries = defaultNumRetries / mult; // reset if HRS has multiplied this already
}
conf.setInt("hbase.client.serverside.retries.multiplier", 1);
int numRetries = conf.getInt(CLIENT_RETRIES_NUMBER, defaultNumRetries);
conf.setInt(HConstants.HBASE_CLIENT_RETRIES_NUMBER, numRetries);
this.numWriterThreads = this.conf.getInt(
"hbase.region.replica.replication.writer.threads", 3);
controller = new PipelineController();
entryBuffers = new EntryBuffers(controller,
this.conf.getInt("hbase.region.replica.replication.buffersize",
128*1024*1024));
// use the regular RPC timeout for replica replication RPC's
this.operationTimeout = conf.getInt(HConstants.HBASE_CLIENT_OPERATION_TIMEOUT,
HConstants.DEFAULT_HBASE_CLIENT_OPERATION_TIMEOUT);
}
@Override
protected void doStart() {
try {
connection = (ClusterConnection) ConnectionFactory.createConnection(this.conf);
this.pool = getDefaultThreadPool(conf);
outputSink = new RegionReplicaOutputSink(controller, tableDescriptors, entryBuffers,
connection, pool, numWriterThreads, operationTimeout);
outputSink.startWriterThreads();
super.doStart();
} catch (IOException ex) {
LOG.warn("Received exception while creating connection :" + ex);
notifyFailed(ex);
}
}
@Override
protected void doStop() {
if (outputSink != null) {
try {
outputSink.finishWritingAndClose();
} catch (IOException ex) {
LOG.warn("Got exception while trying to close OutputSink");
LOG.warn(ex);
}
}
if (this.pool != null) {
this.pool.shutdownNow();
try {
// wait for 10 sec
boolean shutdown = this.pool.awaitTermination(10000, TimeUnit.MILLISECONDS);
if (!shutdown) {
LOG.warn("Failed to shutdown the thread pool after 10 seconds");
}
} catch (InterruptedException e) {
LOG.warn("Got interrupted while waiting for the thread pool to shut down" + e);
}
}
if (connection != null) {
try {
connection.close();
} catch (IOException ex) {
LOG.warn("Got exception closing connection :" + ex);
}
}
super.doStop();
}
/**
* Returns a Thread pool for the RPC's to region replicas. Similar to
* Connection's thread pool.
*/
private ExecutorService getDefaultThreadPool(Configuration conf) {
int maxThreads = conf.getInt("hbase.region.replica.replication.threads.max", 256);
if (maxThreads == 0) {
maxThreads = Runtime.getRuntime().availableProcessors() * 8;
}
long keepAliveTime = conf.getLong("hbase.region.replica.replication.threads.keepalivetime", 60);
LinkedBlockingQueue<Runnable> workQueue =
new LinkedBlockingQueue<>(maxThreads *
conf.getInt(HConstants.HBASE_CLIENT_MAX_TOTAL_TASKS,
HConstants.DEFAULT_HBASE_CLIENT_MAX_TOTAL_TASKS));
ThreadPoolExecutor tpe = new ThreadPoolExecutor(
maxThreads,
maxThreads,
keepAliveTime,
TimeUnit.SECONDS,
workQueue,
Threads.newDaemonThreadFactory(this.getClass().getSimpleName() + "-rpc-shared-"));
tpe.allowCoreThreadTimeOut(true);
return tpe;
}
@Override
public boolean replicate(ReplicateContext replicateContext) {
/* A note on batching in RegionReplicaReplicationEndpoint (RRRE):
*
* RRRE relies on batching from two different mechanisms. The first is the batching from
* ReplicationSource since RRRE is a ReplicationEndpoint driven by RS. RS reads from a single
* WAL file filling up a buffer of heap size "replication.source.size.capacity"(64MB) or at most
* "replication.source.nb.capacity" entries or until it sees the end of file (in live tailing).
* Then RS passes all the buffered edits in this replicate() call context. RRRE puts the edits
* to the WALSplitter.EntryBuffers which is a blocking buffer space of up to
* "hbase.region.replica.replication.buffersize" (128MB) in size. This buffer splits the edits
* based on regions.
*
* There are "hbase.region.replica.replication.writer.threads"(default 3) writer threads which
* pick largest per-region buffer and send it to the SinkWriter (see RegionReplicaOutputSink).
* The SinkWriter in this case will send the wal edits to all secondary region replicas in
* parallel via a retrying rpc call. EntryBuffers guarantees that while a buffer is
* being written to the sink, another buffer for the same region will not be made available to
* writers ensuring regions edits are not replayed out of order.
*
* The replicate() call won't return until all the buffers are sent and ack'd by the sinks so
* that the replication can assume all edits are persisted. We may be able to do a better
* pipelining between the replication thread and output sinks later if it becomes a bottleneck.
*/
while (this.isRunning()) {
try {
for (Entry entry: replicateContext.getEntries()) {
entryBuffers.appendEntry(entry);
}
outputSink.flush(); // make sure everything is flushed
ctx.getMetrics().incrLogEditsFiltered(
outputSink.getSkippedEditsCounter().getAndSet(0));
return true;
} catch (InterruptedException e) {
Thread.currentThread().interrupt();
return false;
} catch (IOException e) {
LOG.warn("Received IOException while trying to replicate"
+ StringUtils.stringifyException(e));
}
}
return false;
}
@Override
public boolean canReplicateToSameCluster() {
return true;
}
@Override
protected WALEntryFilter getScopeWALEntryFilter() {
// we do not care about scope. We replicate everything.
return null;
}
static class RegionReplicaOutputSink extends OutputSink {
private final RegionReplicaSinkWriter sinkWriter;
private final TableDescriptors tableDescriptors;
private final Cache<TableName, Boolean> memstoreReplicationEnabled;
public RegionReplicaOutputSink(PipelineController controller, TableDescriptors tableDescriptors,
EntryBuffers entryBuffers, ClusterConnection connection, ExecutorService pool,
int numWriters, int operationTimeout) {
super(controller, entryBuffers, numWriters);
this.sinkWriter = new RegionReplicaSinkWriter(this, connection, pool, operationTimeout);
this.tableDescriptors = tableDescriptors;
// A cache for the table "memstore replication enabled" flag.
// It has a default expiry of 5 sec. This means that if the table is altered
// with a different flag value, we might miss to replicate for that amount of
// time. But this cache avoid the slow lookup and parsing of the TableDescriptor.
int memstoreReplicationEnabledCacheExpiryMs = connection.getConfiguration()
.getInt("hbase.region.replica.replication.cache.memstoreReplicationEnabled.expiryMs", 5000);
this.memstoreReplicationEnabled = CacheBuilder.newBuilder()
.expireAfterWrite(memstoreReplicationEnabledCacheExpiryMs, TimeUnit.MILLISECONDS)
.initialCapacity(10)
.maximumSize(1000)
.build();
}
@Override
public void append(RegionEntryBuffer buffer) throws IOException {
List<Entry> entries = buffer.getEntryBuffer();
if (entries.isEmpty() || entries.get(0).getEdit().getCells().isEmpty()) {
return;
}
// meta edits (e.g. flush) are always replicated.
// data edits (e.g. put) are replicated if the table requires them.
if (!requiresReplication(buffer.getTableName(), entries)) {
return;
}
sinkWriter.append(buffer.getTableName(), buffer.getEncodedRegionName(),
CellUtil.cloneRow(entries.get(0).getEdit().getCells().get(0)), entries);
}
@Override
public boolean flush() throws IOException {
// nothing much to do for now. Wait for the Writer threads to finish up
// append()'ing the data.
entryBuffers.waitUntilDrained();
return super.flush();
}
@Override
public boolean keepRegionEvent(Entry entry) {
return true;
}
@Override
public List<Path> finishWritingAndClose() throws IOException {
finishWriting(true);
return null;
}
@Override
public Map<byte[], Long> getOutputCounts() {
return null; // only used in tests
}
@Override
public int getNumberOfRecoveredRegions() {
return 0;
}
AtomicLong getSkippedEditsCounter() {
return skippedEdits;
}
/**
* returns true if the specified entry must be replicated.
* We should always replicate meta operations (e.g. flush)
* and use the user HTD flag to decide whether or not replicate the memstore.
*/
private boolean requiresReplication(final TableName tableName, final List<Entry> entries)
throws IOException {
// unit-tests may not the TableDescriptors, bypass the check and always replicate
if (tableDescriptors == null) return true;
Boolean requiresReplication = memstoreReplicationEnabled.getIfPresent(tableName);
if (requiresReplication == null) {
// check if the table requires memstore replication
// some unit-test drop the table, so we should do a bypass check and always replicate.
HTableDescriptor htd = tableDescriptors.get(tableName);
requiresReplication = htd == null || htd.hasRegionMemstoreReplication();
memstoreReplicationEnabled.put(tableName, requiresReplication);
}
// if memstore replication is not required, check the entries.
// meta edits (e.g. flush) must be always replicated.
if (!requiresReplication) {
int skipEdits = 0;
java.util.Iterator<Entry> it = entries.iterator();
while (it.hasNext()) {
Entry entry = it.next();
if (entry.getEdit().isMetaEdit()) {
requiresReplication = true;
} else {
it.remove();
skipEdits++;
}
}
skippedEdits.addAndGet(skipEdits);
}
return requiresReplication;
}
}
static class RegionReplicaSinkWriter extends SinkWriter {
RegionReplicaOutputSink sink;
ClusterConnection connection;
RpcControllerFactory rpcControllerFactory;
RpcRetryingCallerFactory rpcRetryingCallerFactory;
int operationTimeout;
ExecutorService pool;
Cache<TableName, Boolean> disabledAndDroppedTables;
public RegionReplicaSinkWriter(RegionReplicaOutputSink sink, ClusterConnection connection,
ExecutorService pool, int operationTimeout) {
this.sink = sink;
this.connection = connection;
this.operationTimeout = operationTimeout;
this.rpcRetryingCallerFactory
= RpcRetryingCallerFactory.instantiate(connection.getConfiguration());
this.rpcControllerFactory = RpcControllerFactory.instantiate(connection.getConfiguration());
this.pool = pool;
int nonExistentTableCacheExpiryMs = connection.getConfiguration()
.getInt("hbase.region.replica.replication.cache.disabledAndDroppedTables.expiryMs", 5000);
// A cache for non existing tables that have a default expiry of 5 sec. This means that if the
// table is created again with the same name, we might miss to replicate for that amount of
// time. But this cache prevents overloading meta requests for every edit from a deleted file.
disabledAndDroppedTables = CacheBuilder.newBuilder()
.expireAfterWrite(nonExistentTableCacheExpiryMs, TimeUnit.MILLISECONDS)
.initialCapacity(10)
.maximumSize(1000)
.build();
}
public void append(TableName tableName, byte[] encodedRegionName, byte[] row,
List<Entry> entries) throws IOException {
if (disabledAndDroppedTables.getIfPresent(tableName) != null) {
if (LOG.isTraceEnabled()) {
LOG.trace("Skipping " + entries.size() + " entries because table " + tableName
+ " is cached as a disabled or dropped table");
for (Entry entry : entries) {
LOG.trace("Skipping : " + entry);
}
}
sink.getSkippedEditsCounter().addAndGet(entries.size());
return;
}
// If the table is disabled or dropped, we should not replay the entries, and we can skip
// replaying them. However, we might not know whether the table is disabled until we
// invalidate the cache and check from meta
RegionLocations locations = null;
boolean useCache = true;
while (true) {
// get the replicas of the primary region
try {
locations = RegionReplicaReplayCallable
.getRegionLocations(connection, tableName, row, useCache, 0);
if (locations == null) {
throw new HBaseIOException("Cannot locate locations for "
+ tableName + ", row:" + Bytes.toStringBinary(row));
}
} catch (TableNotFoundException e) {
if (LOG.isTraceEnabled()) {
LOG.trace("Skipping " + entries.size() + " entries because table " + tableName
+ " is dropped. Adding table to cache.");
for (Entry entry : entries) {
LOG.trace("Skipping : " + entry);
}
}
disabledAndDroppedTables.put(tableName, Boolean.TRUE); // put to cache. Value ignored
// skip this entry
sink.getSkippedEditsCounter().addAndGet(entries.size());
return;
}
// check whether we should still replay this entry. If the regions are changed, or the
// entry is not coming from the primary region, filter it out.
HRegionLocation primaryLocation = locations.getDefaultRegionLocation();
if (!Bytes.equals(primaryLocation.getRegionInfo().getEncodedNameAsBytes(),
encodedRegionName)) {
if (useCache) {
useCache = false;
continue; // this will retry location lookup
}
if (LOG.isTraceEnabled()) {
LOG.trace("Skipping " + entries.size() + " entries in table " + tableName
+ " because located region " + primaryLocation.getRegionInfo().getEncodedName()
+ " is different than the original region " + Bytes.toStringBinary(encodedRegionName)
+ " from WALEdit");
for (Entry entry : entries) {
LOG.trace("Skipping : " + entry);
}
}
sink.getSkippedEditsCounter().addAndGet(entries.size());
return;
}
break;
}
if (locations.size() == 1) {
return;
}
ArrayList<Future<ReplicateWALEntryResponse>> tasks = new ArrayList<>(locations.size() - 1);
// All passed entries should belong to one region because it is coming from the EntryBuffers
// split per region. But the regions might split and merge (unlike log recovery case).
for (int replicaId = 0; replicaId < locations.size(); replicaId++) {
HRegionLocation location = locations.getRegionLocation(replicaId);
if (!RegionReplicaUtil.isDefaultReplica(replicaId)) {
HRegionInfo regionInfo = location == null
? RegionReplicaUtil.getRegionInfoForReplica(
locations.getDefaultRegionLocation().getRegionInfo(), replicaId)
: location.getRegionInfo();
RegionReplicaReplayCallable callable = new RegionReplicaReplayCallable(connection,
rpcControllerFactory, tableName, location, regionInfo, row, entries,
sink.getSkippedEditsCounter());
Future<ReplicateWALEntryResponse> task = pool.submit(
new RetryingRpcCallable<>(rpcRetryingCallerFactory, callable, operationTimeout));
tasks.add(task);
}
}
boolean tasksCancelled = false;
for (Future<ReplicateWALEntryResponse> task : tasks) {
try {
task.get();
} catch (InterruptedException e) {
throw new InterruptedIOException(e.getMessage());
} catch (ExecutionException e) {
Throwable cause = e.getCause();
if (cause instanceof IOException) {
// The table can be disabled or dropped at this time. For disabled tables, we have no
// cheap mechanism to detect this case because meta does not contain this information.
// ClusterConnection.isTableDisabled() is a zk call which we cannot do for every replay
// RPC. So instead we start the replay RPC with retries and check whether the table is
// dropped or disabled which might cause SocketTimeoutException, or
// RetriesExhaustedException or similar if we get IOE.
if (cause instanceof TableNotFoundException || connection.isTableDisabled(tableName)) {
if (LOG.isTraceEnabled()) {
LOG.trace("Skipping " + entries.size() + " entries in table " + tableName
+ " because received exception for dropped or disabled table", cause);
for (Entry entry : entries) {
LOG.trace("Skipping : " + entry);
}
}
disabledAndDroppedTables.put(tableName, Boolean.TRUE); // put to cache for later.
if (!tasksCancelled) {
sink.getSkippedEditsCounter().addAndGet(entries.size());
tasksCancelled = true; // so that we do not add to skipped counter again
}
continue;
}
// otherwise rethrow
throw (IOException)cause;
}
// unexpected exception
throw new IOException(cause);
}
}
}
}
static class RetryingRpcCallable<V> implements Callable<V> {
RpcRetryingCallerFactory factory;
RetryingCallable<V> callable;
int timeout;
public RetryingRpcCallable(RpcRetryingCallerFactory factory, RetryingCallable<V> callable,
int timeout) {
this.factory = factory;
this.callable = callable;
this.timeout = timeout;
}
@Override
public V call() throws Exception {
return factory.<V>newCaller().callWithRetries(callable, timeout);
}
}
/**
* Calls replay on the passed edits for the given set of entries belonging to the region. It skips
* the entry if the region boundaries have changed or the region is gone.
*/
static class RegionReplicaReplayCallable extends
RegionAdminServiceCallable<ReplicateWALEntryResponse> {
private final List<Entry> entries;
private final byte[] initialEncodedRegionName;
private final AtomicLong skippedEntries;
public RegionReplicaReplayCallable(ClusterConnection connection,
RpcControllerFactory rpcControllerFactory, TableName tableName,
HRegionLocation location, HRegionInfo regionInfo, byte[] row,List<Entry> entries,
AtomicLong skippedEntries) {
super(connection, rpcControllerFactory, location, tableName, row, regionInfo.getReplicaId());
this.entries = entries;
this.skippedEntries = skippedEntries;
this.initialEncodedRegionName = regionInfo.getEncodedNameAsBytes();
}
public ReplicateWALEntryResponse call(HBaseRpcController controller) throws Exception {
// Check whether we should still replay this entry. If the regions are changed, or the
// entry is not coming form the primary region, filter it out because we do not need it.
// Regions can change because of (1) region split (2) region merge (3) table recreated
boolean skip = false;
if (!Bytes.equals(location.getRegionInfo().getEncodedNameAsBytes(),
initialEncodedRegionName)) {
skip = true;
}
if (!this.entries.isEmpty() && !skip) {
Entry[] entriesArray = new Entry[this.entries.size()];
entriesArray = this.entries.toArray(entriesArray);
// set the region name for the target region replica
Pair<AdminProtos.ReplicateWALEntryRequest, CellScanner> p =
ReplicationProtbufUtil.buildReplicateWALEntryRequest(entriesArray, location
.getRegionInfo().getEncodedNameAsBytes(), null, null, null);
controller.setCellScanner(p.getSecond());
return stub.replay(controller, p.getFirst());
}
if (skip) {
if (LOG.isTraceEnabled()) {
LOG.trace("Skipping " + entries.size() + " entries in table " + tableName
+ " because located region " + location.getRegionInfo().getEncodedName()
+ " is different than the original region "
+ Bytes.toStringBinary(initialEncodedRegionName) + " from WALEdit");
for (Entry entry : entries) {
LOG.trace("Skipping : " + entry);
}
}
skippedEntries.addAndGet(entries.size());
}
return ReplicateWALEntryResponse.newBuilder().build();
}
}
}