package org.infinispan.persistence.sifs;
import java.io.IOException;
import java.util.Iterator;
import java.util.concurrent.Executor;
import java.util.concurrent.atomic.AtomicLong;
import org.infinispan.commons.equivalence.Equivalence;
import org.infinispan.commons.io.ByteBuffer;
import org.infinispan.commons.io.ByteBufferFactory;
import org.infinispan.commons.marshall.StreamingMarshaller;
import org.infinispan.commons.persistence.Store;
import org.infinispan.filter.KeyFilter;
import org.infinispan.marshall.core.MarshalledEntry;
import org.infinispan.marshall.core.MarshalledEntryFactory;
import org.infinispan.metadata.InternalMetadata;
import org.infinispan.persistence.PersistenceUtil;
import org.infinispan.persistence.TaskContextImpl;
import org.infinispan.persistence.sifs.configuration.SoftIndexFileStoreConfiguration;
import org.infinispan.persistence.spi.AdvancedLoadWriteStore;
import org.infinispan.persistence.spi.InitializationContext;
import org.infinispan.persistence.spi.PersistenceException;
import org.infinispan.util.TimeService;
import org.infinispan.util.logging.Log;
import org.infinispan.util.logging.LogFactory;
/**
* Local file-based cache store, optimized for write-through use with strong consistency guarantees
* (ability to flush disk operations before returning from the store call).
*
* * DESIGN:
* There are three threads operating in the cache-store:
* - LogAppender: Requests to store entries are passed to the LogAppender thread
* via queue, then the requestor threads wait until LogAppender notifies
* them about successful store. LogAppender serializes the writes
* into append-only file, writes the offset into TemporaryTable
* and enqueues request to update index into UpdateQueue.
* The append-only files have limited size, when the file is full,
* new file is started.
* - IndexUpdater: Reads the UpdateQueue, applies the operation into B-tree-like
* structure Index (exact description below) and then removes
* the entry from TemporaryTable. When the Index is overwriten,
* the current entry offset is retrieved and IndexUpdater increases
* the unused space statistics in FileStats.
* - Compactor: When a limit of unused space in some file is reached (according
* to FileStats), the Compactor starts reading this file sequentially,
* querying TemporaryTable or Index for the current entry position
* and copying the unchanged entries into another file. For the entries
* that are still valid in the original file, a compare-and-set
* (file-offset based) request is enqueued into UpdateQueue - therefore
* this operation cannot interfere with concurrent writes overwriting
* the entry. Multiple files can be merged into single file during
* compaction.
*
* Structures:
* - TemporaryTable: keeps the records about current entry location until this is
* applied to the Index. Each read request goes to the TemporaryTable,
* if the key is not found here, Index is queried.
* - UpdateQueue: bounded queue (to prevent grow the TemporaryTable too much) of either
* forced writes (used for regular stores) or compare-and-set writes
* (used by Compactor).
* - FileStats: simple (Concurrent)HashTable with actual file size and amount of unused
* space for each file.
* - Index: B+-tree of IndexNodes. The tree is dropped and built a new if the process
* crashes, it does not need to flush disk operations. On disk it is kept as single random-accessed file, with free blocks list stored in memory.
*
* As IndexUpdater may easily become a bottleneck under heavy load, the IndexUpdater thread,
* UpdateQueue and tree of IndexNodes may be multiplied several times - the Index is divided
* into Segments. Each segment owns keys according to the hashCode() of the key.
*
* Amount of entries in IndexNode is limited by the size it occupies on disk. This size is
* limited by configurable nodeSize (4096 bytes by default?), only in case that the node
* contains single pivot (too long) it can be longer. A key_prefix common for all keys
* in the IndexNode is stored in order to reduce space requirements. For implementation
* reasons the keys are limited to 32kB - this requirement may be circumvented later.
*
* The pivots are not whole keys - it is the shortest part of key that is greater than all
* left children (but lesser or equal to all right children) - let us call this key_part.
* The key_parts are sorted in the IndexNode, naturally. On disk it has this format:
*
* key_prefix_length(2 bytes), key_prefix, num_parts(2 bytes),
* ( key_part_length (2 bytes), key_part, left_child_index_node_offset (8 bytes))+,
* right_child_index_node_offset (8 bytes)
*
* In memory, for every child a SoftReference<IndexNode> is held. When this reference
* is empty (but the offset in file is set), any reader may load the reference using
* double-locking pattern (synchronized over the reference itself). The entry is never
* loaded by multiple threads in parallel and even may block other threads trying to
* read this node.
*
* For each node in memory a RW-lock is held. When the IndexUpdater thread updates
* the Index (modifying some IndexNodes), it prepares a copy of these nodes (already
* stored into index file). Then, in locks only the uppermost node for writing, overwrites
* the references to new data and unlocks the this node. After that the changed nodes are
* traversed from top down, write locked and their record in index file is released.
* Reader threads crawl the tree from top down, locking the parent node (for reading),
* locking child node and unlocking parent node.
*
* @author Radim Vansa <rvansa@redhat.com>
*/
@Store
public class SoftIndexFileStore implements AdvancedLoadWriteStore {
private static final Log log = LogFactory.getLog(SoftIndexFileStore.class);
private static final boolean trace = log.isTraceEnabled();
private SoftIndexFileStoreConfiguration configuration;
private boolean started = false;
private TemporaryTable temporaryTable;
private IndexQueue indexQueue;
private SyncProcessingQueue<LogRequest> storeQueue;
private FileProvider fileProvider;
private LogAppender logAppender;
private Index index;
private Compactor compactor;
private StreamingMarshaller marshaller;
private ByteBufferFactory byteBufferFactory;
private MarshalledEntryFactory marshalledEntryFactory;
private TimeService timeService;
private Equivalence<Object> keyEquivalence;
private int maxKeyLength;
@Override
public void init(InitializationContext ctx) {
configuration = ctx.getConfiguration();
marshaller = ctx.getMarshaller();
marshalledEntryFactory = ctx.getMarshalledEntryFactory();
byteBufferFactory = ctx.getByteBufferFactory();
timeService = ctx.getTimeService();
keyEquivalence = ctx.getCache().getAdvancedCache().getCacheConfiguration().dataContainer().keyEquivalence();
maxKeyLength = configuration.maxNodeSize() - IndexNode.RESERVED_SPACE;
}
@Override
public void start() {
if (started) {
throw new IllegalStateException("This store is already started!");
}
started = true;
temporaryTable = new TemporaryTable(configuration.indexQueueLength() * configuration.indexSegments());
storeQueue = new SyncProcessingQueue<LogRequest>();
indexQueue = new IndexQueue(configuration.indexSegments(), configuration.indexQueueLength(), keyEquivalence);
fileProvider = new FileProvider(configuration.dataLocation(), configuration.openFilesLimit());
compactor = new Compactor(fileProvider, temporaryTable, indexQueue, marshaller, timeService, configuration.maxFileSize(), configuration.compactionThreshold());
logAppender = new LogAppender(storeQueue, indexQueue, temporaryTable, compactor, fileProvider, configuration.syncWrites(), configuration.maxFileSize());
try {
index = new Index(fileProvider, configuration.indexLocation(), configuration.indexSegments(),
configuration.minNodeSize(), configuration.maxNodeSize(),
indexQueue, temporaryTable, compactor, timeService, keyEquivalence);
} catch (IOException e) {
throw new PersistenceException("Cannot open index file in " + configuration.indexLocation(), e);
}
compactor.setIndex(index);
startIndex();
final AtomicLong maxSeqId = new AtomicLong(0);
if (index.isLoaded()) {
log.debug("Not building the index - loaded from persisted state");
} else if (configuration.purgeOnStartup()) {
log.debug("Not building the index - purge will be executed");
} else {
log.debug("Building the index");
forEachOnDisk(false, false, new EntryFunctor() {
@Override
public boolean apply(int file, int offset, int size, byte[] serializedKey, byte[] serializedMetadata, byte[] serializedValue, long seqId, long expiration) throws IOException, ClassNotFoundException {
long prevSeqId;
while (seqId > (prevSeqId = maxSeqId.get()) && !maxSeqId.compareAndSet(prevSeqId, seqId)) {
}
Object key = marshaller.objectFromByteBuffer(serializedKey);
if (trace) {
log.tracef("Loaded %d:%d (seqId %d, expiration %d)", file, offset, seqId, expiration);
}
try {
// We may check the seqId safely as we are the only thread writing to index
if (isSeqIdOld(seqId, key, serializedKey)) {
indexQueue.put(IndexRequest.foundOld(key, serializedKey, file, offset));
return true;
}
temporaryTable.set(key, file, offset);
indexQueue.put(IndexRequest.update(key, serializedKey, file, offset, size));
} catch (InterruptedException e) {
log.error("Interrupted building of index, the index won't be built properly!", e);
return false;
}
return true;
}
}, new FileFunctor() {
@Override
public void afterFile(int file) {
compactor.completeFile(file);
}
});
}
logAppender.setSeqId(maxSeqId.get() + 1);
}
protected boolean isSeqIdOld(long seqId, Object key, byte[] serializedKey) throws IOException {
for (; ; ) {
EntryPosition entry = temporaryTable.get(key);
if (entry == null) {
entry = index.getInfo(key, serializedKey);
}
if (entry == null) {
if (trace) {
log.trace("Did not found position for " + key);
}
return false;
} else {
FileProvider.Handle handle = fileProvider.getFile(entry.file);
if (handle == null) {
// the file was deleted after we've looked up temporary table/index
continue;
}
try {
int entryOffset = entry.offset < 0 ? ~entry.offset : entry.offset;
EntryHeader header = EntryRecord.readEntryHeader(handle, entryOffset);
if (header == null) {
throw new IOException("Cannot read " + entry.file + ":" + entryOffset);
}
if (trace) {
log.tracef("SeqId on %d:%d is %d", entry.file, entry.offset, header.seqId());
}
return seqId < header.seqId();
} finally {
handle.close();
}
}
}
}
protected void startIndex() {
// this call is extracted for better testability
index.start();
}
protected boolean isIndexLoaded() {
return index.isLoaded();
}
@Override
public void stop() {
try {
logAppender.stopOperations();
logAppender = null;
compactor.stopOperations();
compactor = null;
index.stopOperations();
index = null;
fileProvider.stop();
fileProvider = null;
temporaryTable = null;
indexQueue = null;
storeQueue = null;
} catch (InterruptedException e) {
throw new PersistenceException("Cannot stop cache store", e);
} finally {
started = false;
}
}
@Override
public synchronized void clear() throws PersistenceException {
try {
logAppender.clearAndPause();
compactor.clearAndPause();
} catch (InterruptedException e) {
throw new PersistenceException("Cannot pause cache store to clear it.", e);
}
try {
index.clear();
} catch (IOException e) {
throw new PersistenceException("Cannot clear/reopen index!", e);
}
try {
fileProvider.clear();
} catch (IOException e) {
throw new PersistenceException("Cannot clear data directory!", e);
}
temporaryTable.clear();
compactor.resumeAfterPause();
logAppender.resumeAfterPause();
}
@Override
public synchronized int size() {
try {
logAppender.pause();
long size = index.size();
return size > Integer.MAX_VALUE ? Integer.MAX_VALUE : (int) size;
} catch (InterruptedException e) {
log.error("Interrupted", e);
Thread.currentThread().interrupt();
return -1;
} finally {
logAppender.resumeAfterPause();
}
}
@Override
public void purge(Executor threadPool, PurgeListener listener) {
log.trace("Purge method not supported, ignoring.");
// TODO: in future we may support to force compactor run on all files
}
@Override
public void write(MarshalledEntry entry) {
int keyLength = entry.getKeyBytes().getLength();
if (keyLength > maxKeyLength) {
throw new PersistenceException("Configuration 'maxNodeSize' is too low - with maxNodeSize="
+ configuration.maxNodeSize() + " bytes you can use only keys serialized to " + maxKeyLength
+ " bytes (key " + entry.getKey() + " is serialized to " + keyLength + " bytes)");
} else if (keyLength > Short.MAX_VALUE) {
// TODO this limitation could be removed by different key length encoding
throw new PersistenceException("SoftIndexFileStore is limited to keys with serialized size <= 32767 bytes");
}
try {
storeQueue.pushAndWait(LogRequest.storeRequest(entry));
} catch (Exception e) {
throw new PersistenceException(e);
}
}
@Override
public boolean delete(Object key) {
try {
LogRequest request = LogRequest.deleteRequest(key, toBuffer(marshaller.objectToByteBuffer(key)));
storeQueue.pushAndWait(request);
return (Boolean) request.getIndexRequest().getResult();
} catch (Exception e) {
throw new PersistenceException(e);
}
}
@Override
public boolean contains(Object key) {
try {
for (;;) {
// TODO: consider storing expiration timestamp in temporary table
EntryPosition entry = temporaryTable.get(key);
if (entry != null) {
if (entry.offset < 0) {
return false;
}
FileProvider.Handle handle = fileProvider.getFile(entry.file);
if (handle != null) {
try {
EntryHeader header = EntryRecord.readEntryHeader(handle, entry.offset);
if (header == null) {
throw new IllegalStateException("Error reading from " + entry.file + ":" + entry.offset + " | " + handle.getFileSize());
}
return header.expiryTime() < 0 || header.expiryTime() > timeService.wallClockTime();
} finally {
handle.close();
}
}
} else {
EntryPosition position = index.getPosition(key, marshaller.objectToByteBuffer(key));
return position != null;
}
}
} catch (Exception e) {
throw new PersistenceException("Cannot load key from index", e);
}
}
@Override
public MarshalledEntry load(Object key) {
try {
byte[] serializedValue;
byte[] serializedKey;
byte[] serializedMetadata;
for (;;) {
EntryPosition entry = temporaryTable.get(key);
if (entry != null) {
if (entry.offset < 0) {
log.tracef("Entry for key=%s found in temporary table on %d:%d but it is a tombstone", key, entry.file, entry.offset);
return null;
}
FileProvider.Handle handle = fileProvider.getFile(entry.file);
if (handle != null) {
try {
EntryHeader header = EntryRecord.readEntryHeader(handle, entry.offset);
if (header == null) {
throw new IllegalStateException("Error reading from " + entry.file + ":" + entry.offset + " | " + handle.getFileSize());
}
if (header.expiryTime() > 0 && header.expiryTime() <= timeService.wallClockTime()) {
if (trace) {
log.tracef("Entry for key=%s found in temporary table on %d:%d but it is expired", key, entry.file, entry.offset);
}
return null;
}
serializedKey = EntryRecord.readKey(handle, header, entry.offset);
if (header.metadataLength() > 0) {
serializedMetadata = EntryRecord.readMetadata(handle, header, entry.offset);
} else {
serializedMetadata = null;
}
if (header.valueLength() > 0) {
serializedValue = EntryRecord.readValue(handle, header, entry.offset);
if (trace) {
log.tracef("Entry for key=%s found in temporary table on %d:%d and loaded", key, entry.file, entry.offset);
}
} else {
if (trace) {
log.tracef("Entry for key=%s found in temporary table on %d:%d but it is a tombstone in log", key, entry.file, entry.offset);
}
return null;
}
return marshalledEntryFactory.newMarshalledEntry(toBuffer(serializedKey), toBuffer(serializedValue), toBuffer(serializedMetadata));
} finally {
handle.close();
}
}
} else {
EntryRecord record = index.getRecord(key, marshaller.objectToByteBuffer(key));
if (record == null) return null;
return marshalledEntryFactory.newMarshalledEntry(toBuffer(record.getKey()), toBuffer(record.getValue()), toBuffer(record.getMetadata()));
}
}
} catch (Exception e) {
throw new PersistenceException(e);
}
}
/**
* This method should be called by reflection to get more info about the missing/invalid key (from test tools)
* @param key
* @return
*/
public String debugInfo(Object key) {
EntryPosition entry = temporaryTable.get(key);
if (entry != null) {
return "temporaryTable: " + entry;
} else {
try {
entry = index.getPosition(key, marshaller.objectToByteBuffer(key));
return "index: " + entry;
} catch (Exception e) {
log.debug("Cannot debug key " + key, e);
return "exception: " + e;
}
}
}
private ByteBuffer toBuffer(byte[] array) {
return array == null ? null : byteBufferFactory.newByteBuffer(array, 0, array.length);
}
private interface EntryFunctor {
boolean apply(int file, int offset, int size, byte[] serializedKey, byte[] serializedMetadata, byte[] serializedValue, long seqId, long expiration) throws Exception;
}
private interface FileFunctor {
void afterFile(int file);
}
private void forEachOnDisk(boolean readMetadata, boolean readValues, EntryFunctor functor, FileFunctor fileFunctor) throws PersistenceException {
try {
Iterator<Integer> iterator = fileProvider.getFileIterator();
while (iterator.hasNext()) {
int file = iterator.next();
log.debug("Loading entries from file " + file);
FileProvider.Handle handle = fileProvider.getFile(file);
if (handle == null) {
log.debug("File " + file + " was deleted during iteration");
fileFunctor.afterFile(file);
continue;
}
try {
int offset = 0;
for (;;) {
EntryHeader header = EntryRecord.readEntryHeader(handle, offset);
if (header == null) {
break; // end of file;
}
try {
byte[] serializedKey = EntryRecord.readKey(handle, header, offset);
if (serializedKey == null) {
break; // we have read the file concurrently with writing there
//throw new CacheLoaderException("File " + file + " appears corrupt when reading key from " + offset + ": header is " + header);
}
byte[] serializedMetadata = null;
if (readMetadata && header.metadataLength() > 0) {
serializedMetadata = EntryRecord.readMetadata(handle, header, offset);
}
byte[] serializedValue = null;
int offsetOrNegation = offset;
if (header.valueLength() > 0) {
if (header.expiryTime() >= 0 && header.expiryTime() <= timeService.wallClockTime()) {
offsetOrNegation = ~offset;
} else if (readValues) {
serializedValue = EntryRecord.readValue(handle, header, offset);
}
} else {
offsetOrNegation = ~offset;
}
if (!functor.apply(file, offsetOrNegation, header.totalLength(), serializedKey, serializedMetadata, serializedValue, header.seqId(), header.expiryTime())) {
return;
}
} finally {
offset += header.totalLength();
}
}
} finally {
handle.close();
fileFunctor.afterFile(file);
}
}
} catch (Exception e) {
throw new PersistenceException(e);
}
}
@Override
public void process(KeyFilter filter, final CacheLoaderTask task, final Executor executor, final boolean fetchValue, final boolean fetchMetadata) {
final TaskContext context = new TaskContextImpl();
final KeyFilter notNullFilter = PersistenceUtil.notNull(filter);
final AtomicLong tasksSubmitted = new AtomicLong();
final AtomicLong tasksFinished = new AtomicLong();
forEachOnDisk(fetchMetadata, fetchValue, new EntryFunctor() {
@Override
public boolean apply(int file, int offset, int size,
final byte[] serializedKey, final byte[] serializedMetadata, final byte[] serializedValue,
long seqId, long expiration) throws IOException, ClassNotFoundException {
if (context.isStopped()) {
return false;
}
final Object key = marshaller.objectFromByteBuffer(serializedKey);
if (!notNullFilter.accept(key)) {
return true;
}
if (isSeqIdOld(seqId, key, serializedKey)) {
return true;
}
if (serializedValue != null && (expiration < 0 || expiration > timeService.wallClockTime())) {
executor.execute(new Runnable() {
@Override
public void run() {
try {
task.processEntry(marshalledEntryFactory.newMarshalledEntry(key,
serializedValue == null ? null : marshaller.objectFromByteBuffer(serializedValue),
serializedMetadata == null ? null : (InternalMetadata) marshaller.objectFromByteBuffer(serializedMetadata)),
context);
} catch (Exception e) {
log.error("Failed to process task for key " + key, e);
} finally {
long finished = tasksFinished.incrementAndGet();
if (finished == tasksSubmitted.longValue()) {
synchronized (context) {
context.notifyAll();
}
}
}
}
});
tasksSubmitted.incrementAndGet();
return !context.isStopped();
}
return true;
}
}, new FileFunctor() {
@Override
public void afterFile(int file) {
// noop
}
});
while (tasksSubmitted.longValue() > tasksFinished.longValue()) {
synchronized (context) {
try {
context.wait(100);
} catch (InterruptedException e) {
log.error("Iteration was interrupted", e);
Thread.currentThread().interrupt();
return;
}
}
}
}
}