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Apache Geode provides a database-like consistency model, reliable transaction processing and a shared-nothing architecture to maintain very low latency performance with high concurrency processing
/*
* 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.geode.internal.cache.snapshot;
import org.apache.geode.cache.EntryDestroyedException;
import org.apache.geode.cache.Region;
import org.apache.geode.cache.execute.*;
import org.apache.geode.cache.partition.PartitionRegionHelper;
import org.apache.geode.cache.snapshot.SnapshotOptions;
import org.apache.geode.distributed.DistributedMember;
import org.apache.geode.distributed.internal.DistributionConfig;
import org.apache.geode.distributed.internal.ReplyProcessor21;
import org.apache.geode.internal.cache.LocalRegion;
import org.apache.geode.internal.cache.execute.InternalExecution;
import org.apache.geode.internal.cache.execute.LocalResultCollector;
import org.apache.geode.internal.cache.snapshot.FlowController.Window;
import org.apache.geode.internal.cache.snapshot.RegionSnapshotServiceImpl.ExportSink;
import org.apache.geode.internal.cache.snapshot.RegionSnapshotServiceImpl.Exporter;
import org.apache.geode.internal.cache.snapshot.SnapshotPacket.SnapshotRecord;
import java.io.IOException;
import java.io.InterruptedIOException;
import java.io.Serializable;
import java.util.ArrayList;
import java.util.Iterator;
import java.util.List;
import java.util.Map;
import java.util.Map.Entry;
import java.util.concurrent.BlockingQueue;
import java.util.concurrent.ConcurrentHashMap;
import java.util.concurrent.LinkedBlockingQueue;
import java.util.concurrent.TimeUnit;
import java.util.concurrent.atomic.AtomicBoolean;
import static org.apache.geode.distributed.internal.InternalDistributedSystem.getLoggerI18n;
/**
* Exports snapshot data using a sliding window to prevent the nodes in a partitioned region from
* overrunning the exporter. When a {@link SnapshotPacket} is written to the {@link ExportSink}, an
* ACK is sent back to the source node. The source node will continue to send data until it runs out
* of permits; it must then wait for ACK's to resume.
*
*
* @param the key type
* @param the value type
*/
public class WindowedExporter implements Exporter {
private static final int WINDOW_SIZE =
Integer.getInteger(DistributionConfig.GEMFIRE_PREFIX + "WindowedExporter.WINDOW_SIZE", 10);
@Override
public long export(Region region, ExportSink sink, SnapshotOptions options)
throws IOException {
long count = 0;
boolean error = true;
LocalRegion local = RegionSnapshotServiceImpl.getLocalRegion(region);
SnapshotPacket last = new SnapshotPacket();
DistributedMember me = region.getCache().getDistributedSystem().getDistributedMember();
WindowedArgs args = new WindowedArgs(me, options);
WindowedExportCollector results = new WindowedExportCollector(local, last);
try {
// Since the ExportCollector already is a LocalResultsCollector it's ok not
// to keep the reference to the ResultsCollector returned from execute().
// Normally discarding the reference can cause issues if GC causes the
// weak ref in ProcessorKeeper21 to be collected!!
InternalExecution exec = (InternalExecution) FunctionService.onRegion(region).withArgs(args)
.withCollector(results);
// Ensure that our collector gets all exceptions so we can shut down the
// queue properly.
exec.setForwardExceptions(true);
exec.execute(new WindowedExportFunction());
BlockingQueue queue = results.getResult();
SnapshotPacket packet;
while ((packet = queue.take()) != last) {
results.ack(packet);
sink.write(packet.getRecords());
count += packet.getRecords().length;
}
error = false;
FunctionException ex = results.getException();
if (ex != null) {
throw new IOException(ex);
}
} catch (FunctionException e) {
throw new IOException(e);
} catch (InterruptedException e) {
Thread.currentThread().interrupt();
throw (IOException) new InterruptedIOException().initCause(e);
} finally {
if (error) {
results.abort();
}
}
return count;
}
/**
* Carries the arguments to the export function.
*
* @param the key type
* @param the value type
*/
private static class WindowedArgs implements Serializable {
private static final long serialVersionUID = 1;
private final DistributedMember exporter;
private final SnapshotOptions options;
public WindowedArgs(DistributedMember exporter, SnapshotOptions options) {
this.exporter = exporter;
this.options = options;
}
public DistributedMember getExporter() {
return exporter;
}
public SnapshotOptions getOptions() {
return options;
}
}
/**
* Gathers the local data on the region and sends it back to the {@link ResultCollector} in
* serialized form as {@link SnapshotPacket}s. Uses a sliding window provided by the
* {@link FlowController} to avoid over-running the exporting member.
*
* @param the key type
* @param the value type
*
* @see FlowController
*/
private static class WindowedExportFunction implements Function {
private static final long serialVersionUID = 1L;
// We must keep a ref here since the ProcessorKeeper only has a weak ref. If
// this object is GC'd it could cause a hang since we will no longer receive
// ACK's for every packet.
private transient volatile Window window;
@Override
public boolean hasResult() {
return true;
}
@Override
public void execute(FunctionContext context) {
RegionFunctionContext ctx = (RegionFunctionContext) context;
final WindowedArgs args = (WindowedArgs) ctx.getArguments();
ResultSender rs = ctx.getResultSender();
Region region = ctx.getDataSet();
if (PartitionRegionHelper.isPartitionedRegion(region)) {
region = PartitionRegionHelper.getLocalDataForContext(ctx);
}
LocalRegion local = RegionSnapshotServiceImpl.getLocalRegion(region);
window = FlowController.getInstance().create(region, args.getExporter(), WINDOW_SIZE);
try {
int bufferSize = 0;
List buffer = new ArrayList();
DistributedMember me = region.getCache().getDistributedSystem().getDistributedMember();
for (Iterator> iter = region.entrySet().iterator(); iter.hasNext()
&& !window.isAborted();) {
Entry entry = iter.next();
try {
SnapshotOptions options = args.getOptions();
if (options.getFilter() == null || options.getFilter().accept(entry)) {
SnapshotRecord rec = new SnapshotRecord(local, entry);
buffer.add(rec);
bufferSize += rec.getSize();
}
} catch (EntryDestroyedException e) {
// continue to next entry
} catch (IOException e) {
throw new FunctionException(e);
}
if (bufferSize > RegionSnapshotServiceImpl.BUFFER_SIZE) {
window.waitForOpening();
rs.sendResult(new SnapshotPacket(window.getWindowId(), me, buffer));
buffer.clear();
bufferSize = 0;
}
}
window.waitForOpening();
rs.lastResult(new SnapshotPacket(window.getWindowId(), me, buffer));
if (getLoggerI18n().fineEnabled())
getLoggerI18n().fine("SNP: Sent all entries in region " + region.getName());
} catch (InterruptedException e) {
Thread.currentThread().interrupt();
throw new FunctionException(e);
} finally {
window.close();
}
}
@Override
public String getId() {
return "org.apache.geode.cache.snapshot.WindowedExport";
}
@Override
public boolean optimizeForWrite() {
return false;
}
@Override
public boolean isHA() {
return false;
}
}
/**
* Collects export results and places them in a queue for processing by the function invoker.
*/
private static class WindowedExportCollector
implements LocalResultCollector> {
/** the region being exported */
private final LocalRegion region;
/** marks the end of the queue */
private final SnapshotPacket end;
/** queue used to stream the snapshot entries */
private final BlockingQueue entries;
/** true if no more results are expected */
private final AtomicBoolean done;
/** the members involved in the export */
private final Map members;
/** set if there is an error during execution */
private volatile FunctionException exception;
/** store a ref to the processor to prevent the processor from being GC'd */
private volatile ReplyProcessor21 processor;
public WindowedExportCollector(LocalRegion region, SnapshotPacket end) {
this.region = region;
this.end = end;
done = new AtomicBoolean(false);
members = new ConcurrentHashMap();
// cannot bound queue to exert back pressure
entries = new LinkedBlockingQueue();
}
@Override
public BlockingQueue getResult() throws FunctionException {
return entries;
}
@Override
public BlockingQueue getResult(long timeout, TimeUnit unit)
throws FunctionException, InterruptedException {
return getResult();
}
/**
* Returns an exception that occurred during function exception.
*
* @return the exception, or null
*/
public FunctionException getException() {
return exception;
}
/**
* Aborts any further collection of results and forwards the cancellation to the members
* involved in the export.
*/
public void abort() {
try {
if (done.compareAndSet(false, true)) {
if (getLoggerI18n().fineEnabled())
getLoggerI18n().fine("SNP: Aborting export of region");
entries.clear();
entries.put(end);
for (Entry entry : members.entrySet()) {
sendAbort(entry.getKey(), entry.getValue());
}
}
} catch (InterruptedException e) {
Thread.currentThread().interrupt();
}
}
public void ack(SnapshotPacket packet) {
FlowController.getInstance().sendAck(region.getDistributionManager(), packet.getSender(),
packet.getWindowId(), packet.getPacketId());
}
@Override
public void addResult(DistributedMember memberID, Object result) {
// need to track participants so we can send acks and aborts
if (!(result instanceof Throwable)) {
int flowId = ((SnapshotPacket) result).getWindowId();
if (done.get()) {
sendAbort(memberID, flowId);
} else {
members.put(memberID, flowId);
}
}
if (!done.get()) {
try {
if (result instanceof Throwable) {
setException((Throwable) result);
endResults();
} else {
SnapshotPacket sp = (SnapshotPacket) result;
entries.put(sp);
}
} catch (InterruptedException e) {
Thread.currentThread().interrupt();
}
}
}
@Override
public void endResults() {
try {
if (done.compareAndSet(false, true)) {
if (getLoggerI18n().fineEnabled())
getLoggerI18n()
.fine("SNP: All results received for export of region " + region.getName());
entries.put(end);
}
} catch (InterruptedException e) {
Thread.currentThread().interrupt();
}
}
@Override
public void clearResults() {
entries.clear();
done.set(false);
exception = null;
}
@Override
public void setException(Throwable ex) {
exception =
(ex instanceof FunctionException) ? (FunctionException) ex : new FunctionException(ex);
}
@Override
public void setProcessor(ReplyProcessor21 processor) {
this.processor = processor;
}
@Override
public ReplyProcessor21 getProcessor() {
return processor;
}
private void sendAbort(DistributedMember member, int flowId) {
FlowController.getInstance().sendAbort(region.getDistributionManager(), flowId, member);
}
}
}