/*
Copyright (C) SYSTAP, LLC DBA Blazegraph 2006-2016. All rights reserved.
Contact:
SYSTAP, LLC DBA Blazegraph
2501 Calvert ST NW #106
Washington, DC 20008
licenses@blazegraph.com
This program is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation; version 2 of the License.
This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU General Public License for more details.
You should have received a copy of the GNU General Public License
along with this program; if not, write to the Free Software
Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
*/
/*
* Created on Apr 16, 2009
*/
package com.bigdata.service.ndx.pipeline;
import java.io.IOException;
import java.util.concurrent.ExecutionException;
import java.util.concurrent.Future;
import com.bigdata.btree.keys.KVO;
import com.bigdata.btree.proc.IAsyncResultHandler;
import com.bigdata.btree.proc.IKeyArrayIndexProcedure;
import com.bigdata.mdi.PartitionLocator;
import com.bigdata.relation.accesspath.BlockingBuffer;
import com.bigdata.resources.StaleLocatorException;
import com.bigdata.service.DataService;
import com.bigdata.service.IDataService;
import com.bigdata.service.Split;
import com.bigdata.util.InnerCause;
/**
* Class drains a {@link BlockingBuffer} writing on a specific index
* partition.
*
* @author <a href="mailto:thompsonbry@users.sourceforge.net">Bryan Thompson</a>
* @version $Id$
*/
public class IndexPartitionWriteTask<//
H extends IndexAsyncWriteStats<L, HS>, //
O extends Object, //
E extends KVO<O>, //
L extends PartitionLocator, //
S extends IndexPartitionWriteTask, //
HS extends IndexPartitionWriteStats,//
M extends IndexWriteTask<H, O, E, S, L, HS, T, R, A>,//
T extends IKeyArrayIndexProcedure,//
R,//
A//
> extends AbstractSubtask<HS, M, E, L> {
/**
* The data service on which the index partition resides.
*/
public final IDataService dataService;
/**
* The timestamp associated with the index view.
*/
public final long timestamp;
/**
* The index partition identifier.
*/
public final int partitionId;
/**
* The name of the index partition.
*/
private final String indexPartitionName;
public String toString() {
return getClass().getName() + "{indexPartition=" + indexPartitionName
+ ", open=" + buffer.isOpen() + "}";
}
public IndexPartitionWriteTask(final M master,
final L locator, final IDataService dataService,
final BlockingBuffer<E[]> buffer) {
super(master,locator,buffer);
if (dataService == null)
throw new IllegalArgumentException();
this.dataService = dataService;
this.timestamp = master.ndx.getTimestamp();
this.partitionId = locator.getPartitionId();
this.indexPartitionName = DataService.getIndexPartitionName(master.ndx
.getName(), partitionId);
}
/**
* {@inheritDoc}
*
* Maps the chunk across the sinks for the index partitions on which the
* element in that chunk must be written.
*
* @param sourceChunk
* A chunk (in sorted order).
*
* @return <code>true</code> iff a {@link StaleLocatorException} was
* handled, in which case the task should exit immediately.
*
* @throws IOException
* RMI error.
* @throws ExecutionException
* @throws InterruptedException
*/
protected boolean handleChunk(final E[] sourceChunk)
throws ExecutionException, InterruptedException, IOException {
/*
* Remove duplicates in a caller specified manner (may be a NOP).
*
* Note: Duplicate removal is applied in a single-threaded context by
* the sink against an unchanging KVO[] chunk. Concurrency problems can
* not arise from duplicate elimination.
*/
final KVO<O>[] chunk;
final int duplicateCount;
if (master.duplicateRemover == null) {
chunk = sourceChunk;
duplicateCount = 0;
} else {
// filter out duplicates.
chunk = master.duplicateRemover.filter(sourceChunk);
// #of duplicates that were filtered out.
duplicateCount = sourceChunk.length - chunk.length;
if (duplicateCount > 0 && log.isDebugEnabled())
log.debug("Filtered out " + duplicateCount
+ " duplicates from " + chunk.length + " elements");
}
if (chunk.length == 0) {
// empty chunk after duplicate elimination (keep reading).
return false;
}
// size of the chunk to be processed.
final int chunkSize = chunk.length;
/*
* Change the shape of the data for RMI.
*/
final boolean sendValues = master.ctor.sendValues();
final byte[][] keys = new byte[chunkSize][];
final byte[][] vals = sendValues ? new byte[chunkSize][] : null;
for (int i = 0; i < chunkSize; i++) {
keys[i] = chunk[i].key;
if (sendValues)
vals[i] = chunk[i].val;
}
/*
* Instantiate the procedure using the data from the chunk and submit it
* to be executed on the DataService using an RMI call.
*/
final long beginNanos = System.nanoTime();
try {
final T proc = master.ctor.newInstance(master.ndx,
0/* fromIndex */, chunkSize/* toIndex */, keys, vals);
/*
* @todo isolate this as a retry policy, but note that we need to be
* able to indicate when the error is fatal, when the error was
* handled by a redirect and hence the sink should close, and when
* the error was handled by a successful retry.
*/
R result = null;
boolean done = false;
final int maxtries = 3;
// final long retryDelayNanos = TimeUnit.MILLISECONDS.toNanos(1000);
for (int ntries = 0; ntries < maxtries; ntries++) {
// submit and await Future
try {
result = ((Future<R>) dataService.submit(timestamp,
indexPartitionName, proc)).get();
done = true;
break;
} catch (ExecutionException ex) {
final StaleLocatorException cause = (StaleLocatorException) InnerCause
.getInnerCause(ex, StaleLocatorException.class);
if (cause != null) {
// Handle a stale locator.
handleRedirect((E[]) chunk, cause);
// done.
return true;
} else {
if (ntries + 1 < maxtries) {
log.error("Will retry (" + ntries + " of "
+ maxtries + "): " + this, ex);
continue;
}
log.fatal(this, ex);
throw ex;
}
}
}
if (!done) {
// should not reach this point.
throw new AssertionError();
}
if (master.resultHandler != null) {
// aggregate results.
master.resultHandler.aggregate(result, new Split(locator,
0/* fromIndex */, chunkSize/* toIndex */));
if(master.resultHandler instanceof IAsyncResultHandler) {
// aggregate results.
((IAsyncResultHandler<R, A, O, KVO<O>>) master.resultHandler)
.aggregateAsync(chunk, result, new Split(locator,
0/* fromIndex */, chunkSize/* toIndex */));
}
}
if (log.isDebugEnabled())
log.debug(stats);
/*
* Since the chunk was successfully written, we now rip through the
* KVOs and invoke done() on each. If there are duplicates and
* KVOList was used, then done() will be mapped over each duplicate
* as well.
*/
for (int i = 0; i < chunkSize; i++) {
chunk[i].done();
}
// keep reading.
return false;
} finally {
final long elapsedNanos = System.nanoTime() - beginNanos;
// update the local statistics.
synchronized (stats) {
stats.chunksOut.incrementAndGet();
stats.elementsOut.addAndGet(chunkSize);
stats.elapsedChunkWritingNanos += elapsedNanos;
}
// update the master's statistics.
synchronized (master.stats) {
master.stats.chunksOut.incrementAndGet();
master.stats.elementsOut.addAndGet(chunkSize);
master.stats.duplicateCount.addAndGet(duplicateCount);
master.stats.elapsedSinkChunkWritingNanos += elapsedNanos;
}
}
}
/**
* Notifies the client that the locator is stale.
*/
@Override
protected void notifyClientOfRedirect(L locator, Throwable cause) {
master.ndx.staleLocator(master.ndx.getTimestamp(), (L) locator,
(StaleLocatorException) cause);
}
}