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/*
* 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.solr.store.blockcache;
import java.io.File;
import java.io.FileNotFoundException;
import java.io.IOException;
import java.lang.invoke.MethodHandles;
import java.util.Set;
import org.apache.lucene.index.IndexFileNames;
import org.apache.lucene.store.Directory;
import org.apache.lucene.store.FSDirectory;
import org.apache.lucene.store.FilterDirectory;
import org.apache.lucene.store.IOContext;
import org.apache.lucene.store.IndexInput;
import org.apache.lucene.store.IndexOutput;
import org.apache.solr.core.ShutdownAwareDirectory;
import org.apache.solr.store.hdfs.HdfsDirectory;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
/**
* @lucene.experimental
*/
public class BlockDirectory extends FilterDirectory implements ShutdownAwareDirectory {
private static final Logger log = LoggerFactory.getLogger(MethodHandles.lookup().lookupClass());
public static final long BLOCK_SHIFT = Integer.getInteger("solr.hdfs.blockcache.blockshift", 13);
public static final int BLOCK_SIZE = 1 << BLOCK_SHIFT;
public static final long BLOCK_MOD = BLOCK_SIZE - 1;
public static long getBlock(long pos) {
return pos >>> BLOCK_SHIFT;
}
public static long getPosition(long pos) {
return pos & BLOCK_MOD;
}
public static long getRealPosition(long block, long positionInBlock) {
return (block << BLOCK_SHIFT) + positionInBlock;
}
public static Cache NO_CACHE = new Cache() {
@Override
public void update(String name, long blockId, int blockOffset,
byte[] buffer, int offset, int length) {}
@Override
public boolean fetch(String name, long blockId, int blockOffset, byte[] b,
int off, int lengthToReadInBlock) {
return false;
}
@Override
public void delete(String name) {
}
@Override
public long size() {
return 0;
}
@Override
public void renameCacheFile(String source, String dest) {}
@Override
public void releaseResources() {}
};
private final int blockSize;
private final String dirName;
private final Cache cache;
private final Set blockCacheFileTypes;
private final boolean blockCacheReadEnabled;
private final boolean blockCacheWriteEnabled;
private boolean cacheMerges;
private boolean cacheReadOnce;
public BlockDirectory(String dirName, Directory directory, Cache cache,
Set blockCacheFileTypes, boolean blockCacheReadEnabled,
boolean blockCacheWriteEnabled) throws IOException {
this(dirName, directory, cache, blockCacheFileTypes, blockCacheReadEnabled, blockCacheWriteEnabled, true, true);
}
public BlockDirectory(String dirName, Directory directory, Cache cache,
Set blockCacheFileTypes, boolean blockCacheReadEnabled,
boolean blockCacheWriteEnabled, boolean cacheMerges, boolean cacheReadOnce) throws IOException {
super(directory);
this.cacheMerges = cacheMerges;
this.cacheReadOnce = cacheReadOnce;
this.dirName = dirName;
blockSize = BLOCK_SIZE;
this.cache = cache;
if (blockCacheFileTypes == null || blockCacheFileTypes.isEmpty()) {
this.blockCacheFileTypes = null;
} else {
this.blockCacheFileTypes = blockCacheFileTypes;
}
this.blockCacheReadEnabled = blockCacheReadEnabled;
if (!blockCacheReadEnabled) {
log.info("Block cache on read is disabled");
}
this.blockCacheWriteEnabled = blockCacheWriteEnabled;
if (!blockCacheWriteEnabled) {
log.info("Block cache on write is disabled");
}
}
private IndexInput openInput(String name, int bufferSize, IOContext context)
throws IOException {
final IndexInput source = super.openInput(name, context);
if (useReadCache(name, context)) {
return new CachedIndexInput(source, blockSize, name,
getFileCacheName(name), cache, bufferSize);
}
return source;
}
private boolean isCachableFile(String name) {
for (String ext : blockCacheFileTypes) {
if (name.endsWith(ext)) {
return true;
}
}
return false;
}
@Override
public IndexInput openInput(final String name, IOContext context)
throws IOException {
return openInput(name, blockSize, context);
}
static class CachedIndexInput extends CustomBufferedIndexInput {
private final Store store;
private IndexInput source;
private final int blockSize;
private final long fileLength;
private final String cacheName;
private final Cache cache;
public CachedIndexInput(IndexInput source, int blockSize, String name,
String cacheName, Cache cache, int bufferSize) {
super(name, bufferSize);
this.source = source;
this.blockSize = blockSize;
fileLength = source.length();
this.cacheName = cacheName;
this.cache = cache;
store = BufferStore.instance(blockSize);
}
@Override
public IndexInput clone() {
CachedIndexInput clone = (CachedIndexInput) super.clone();
clone.source = (IndexInput) source.clone();
return clone;
}
@Override
public long length() {
return source.length();
}
@Override
protected void seekInternal(long pos) throws IOException {}
@Override
protected void readInternal(byte[] b, int off, int len) throws IOException {
long position = getFilePointer();
while (len > 0) {
int length = fetchBlock(position, b, off, len);
position += length;
len -= length;
off += length;
}
}
private int fetchBlock(long position, byte[] b, int off, int len)
throws IOException {
// read whole block into cache and then provide needed data
long blockId = getBlock(position);
int blockOffset = (int) getPosition(position);
int lengthToReadInBlock = Math.min(len, blockSize - blockOffset);
if (checkCache(blockId, blockOffset, b, off, lengthToReadInBlock)) {
return lengthToReadInBlock;
} else {
readIntoCacheAndResult(blockId, blockOffset, b, off,
lengthToReadInBlock);
}
return lengthToReadInBlock;
}
private void readIntoCacheAndResult(long blockId, int blockOffset,
byte[] b, int off, int lengthToReadInBlock) throws IOException {
long position = getRealPosition(blockId, 0);
int length = (int) Math.min(blockSize, fileLength - position);
source.seek(position);
byte[] buf = store.takeBuffer(blockSize);
source.readBytes(buf, 0, length);
System.arraycopy(buf, blockOffset, b, off, lengthToReadInBlock);
cache.update(cacheName, blockId, 0, buf, 0, blockSize);
store.putBuffer(buf);
}
private boolean checkCache(long blockId, int blockOffset, byte[] b,
int off, int lengthToReadInBlock) {
return cache.fetch(cacheName, blockId, blockOffset, b, off,
lengthToReadInBlock);
}
@Override
protected void closeInternal() throws IOException {
source.close();
}
}
@Override
public void closeOnShutdown() throws IOException {
log.info("BlockDirectory closing on shutdown");
// we are shutting down, no need to clean up cache
super.close();
}
@Override
public void close() throws IOException {
try {
String[] files = listAll();
for (String file : files) {
cache.delete(getFileCacheName(file));
}
} catch (FileNotFoundException e) {
// the local file system folder may be gone
} finally {
super.close();
cache.releaseResources();
}
}
String getFileCacheName(String name) throws IOException {
return getFileCacheLocation(name) + ":" + getFileModified(name);
}
private long getFileModified(String name) throws IOException {
if (in instanceof FSDirectory) {
File directory = ((FSDirectory) in).getDirectory().toFile();
File file = new File(directory, name);
if (!file.exists()) {
throw new FileNotFoundException("File [" + name + "] not found");
}
return file.lastModified();
} else if (in instanceof HdfsDirectory) {
return ((HdfsDirectory) in).fileModified(name);
} else {
throw new UnsupportedOperationException();
}
}
String getFileCacheLocation(String name) {
return dirName + "/" + name;
}
/**
* Expert: mostly for tests
*
* @lucene.experimental
*/
public Cache getCache() {
return cache;
}
/**
* Determine whether read caching should be used for a particular
* file/context.
*/
boolean useReadCache(String name, IOContext context) {
if (!blockCacheReadEnabled) {
return false;
}
if (blockCacheFileTypes != null && !isCachableFile(name)) {
return false;
}
switch (context.context) {
// depending on params, we don't cache on merges or when only reading once
case MERGE: {
return cacheMerges;
}
case READ: {
if (context.readOnce) {
return cacheReadOnce;
} else {
return true;
}
}
default: {
return true;
}
}
}
/**
* Determine whether write caching should be used for a particular
* file/context.
*/
boolean useWriteCache(String name, IOContext context) {
if (!blockCacheWriteEnabled || name.startsWith(IndexFileNames.PENDING_SEGMENTS)) {
// for safety, don't bother caching pending commits.
// the cache does support renaming (renameCacheFile), but thats a scary optimization.
return false;
}
if (blockCacheFileTypes != null && !isCachableFile(name)) {
return false;
}
switch (context.context) {
case MERGE: {
// we currently don't cache any merge context writes
return false;
}
default: {
return true;
}
}
}
@Override
public IndexOutput createOutput(String name, IOContext context)
throws IOException {
final IndexOutput dest = super.createOutput(name, context);
if (useWriteCache(name, context)) {
return new CachedIndexOutput(this, dest, blockSize, name, cache, blockSize);
}
return dest;
}
public void deleteFile(String name) throws IOException {
cache.delete(getFileCacheName(name));
super.deleteFile(name);
}
public boolean isBlockCacheReadEnabled() {
return blockCacheReadEnabled;
}
public boolean isBlockCacheWriteEnabled() {
return blockCacheWriteEnabled;
}
}
