/**
* Copyright 2007 The Apache Software Foundation
*
* 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;
import java.io.IOException;
import java.io.UnsupportedEncodingException;
import java.util.ArrayList;
import java.util.Collections;
import java.util.HashMap;
import java.util.Iterator;
import java.util.List;
import java.util.Map;
import java.util.SortedMap;
import java.util.TreeMap;
import java.util.Map.Entry;
import java.util.concurrent.atomic.AtomicInteger;
import java.util.concurrent.locks.ReentrantReadWriteLock;
import java.util.regex.Matcher;
import java.util.regex.Pattern;
import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;
import org.apache.hadoop.fs.FSDataInputStream;
import org.apache.hadoop.fs.FSDataOutputStream;
import org.apache.hadoop.fs.FileSystem;
import org.apache.hadoop.fs.Path;
import org.apache.hadoop.hbase.filter.RowFilterInterface;
import org.apache.hadoop.hbase.io.ImmutableBytesWritable;
import org.apache.hadoop.hbase.io.TextSequence;
import org.apache.hadoop.io.MapFile;
import org.apache.hadoop.io.SequenceFile;
import org.apache.hadoop.io.Text;
import org.apache.hadoop.io.Writable;
import org.apache.hadoop.io.WritableComparable;
import org.apache.hadoop.util.StringUtils;
import org.onelab.filter.BloomFilter;
import org.onelab.filter.CountingBloomFilter;
import org.onelab.filter.Filter;
import org.onelab.filter.RetouchedBloomFilter;
/**
* HStore maintains a bunch of data files. It is responsible for maintaining
* the memory/file hierarchy and for periodic flushes to disk and compacting
* edits to the file.
*
* Locking and transactions are handled at a higher level. This API should not
* be called directly by any writer, but rather by an HRegion manager.
*/
public class HStore implements HConstants {
static final Log LOG = LogFactory.getLog(HStore.class);
/**
* The Memcache holds in-memory modifications to the HRegion. This is really a
* wrapper around a TreeMap that helps us when staging the Memcache out to disk.
*/
static class Memcache {
// Note that since these structures are always accessed with a lock held,
// no additional synchronization is required.
@SuppressWarnings("hiding")
private final SortedMap<HStoreKey, byte[]> memcache =
Collections.synchronizedSortedMap(new TreeMap<HStoreKey, byte []>());
volatile SortedMap<HStoreKey, byte[]> snapshot;
@SuppressWarnings("hiding")
private final ReentrantReadWriteLock lock = new ReentrantReadWriteLock();
/**
* Constructor
*/
Memcache() {
snapshot =
Collections.synchronizedSortedMap(new TreeMap<HStoreKey, byte []>());
}
/**
* Creates a snapshot of the current Memcache
*/
void snapshot() {
this.lock.writeLock().lock();
try {
synchronized (memcache) {
if (memcache.size() != 0) {
snapshot.putAll(memcache);
memcache.clear();
}
}
} finally {
this.lock.writeLock().unlock();
}
}
/**
* @return memcache snapshot
*/
SortedMap<HStoreKey, byte[]> getSnapshot() {
this.lock.writeLock().lock();
try {
SortedMap<HStoreKey, byte[]> currentSnapshot = snapshot;
snapshot =
Collections.synchronizedSortedMap(new TreeMap<HStoreKey, byte []>());
return currentSnapshot;
} finally {
this.lock.writeLock().unlock();
}
}
/**
* Store a value.
* @param key
* @param value
*/
void add(final HStoreKey key, final byte[] value) {
this.lock.readLock().lock();
try {
memcache.put(key, value);
} finally {
this.lock.readLock().unlock();
}
}
/**
* Look back through all the backlog TreeMaps to find the target.
* @param key
* @param numVersions
* @return An array of byte arrays ordered by timestamp.
*/
List<byte[]> get(final HStoreKey key, final int numVersions) {
this.lock.readLock().lock();
try {
List<byte []> results;
synchronized (memcache) {
results = internalGet(memcache, key, numVersions);
}
synchronized (snapshot) {
results.addAll(results.size(),
internalGet(snapshot, key, numVersions - results.size()));
}
return results;
} finally {
this.lock.readLock().unlock();
}
}
/**
* Return all the available columns for the given key. The key indicates a
* row and timestamp, but not a column name.
*
* The returned object should map column names to byte arrays (byte[]).
* @param key
* @param results
*/
void getFull(HStoreKey key, Map<Text, Long> deletes,
SortedMap<Text, byte[]> results) {
this.lock.readLock().lock();
try {
synchronized (memcache) {
internalGetFull(memcache, key, deletes, results);
}
synchronized (snapshot) {
internalGetFull(snapshot, key, deletes, results);
}
} finally {
this.lock.readLock().unlock();
}
}
private void internalGetFull(SortedMap<HStoreKey, byte []> map, HStoreKey key,
Map<Text, Long> deletes, SortedMap<Text, byte []> results) {
if (map.isEmpty() || key == null) {
return;
}
SortedMap<HStoreKey, byte []> tailMap = map.tailMap(key);
for (Map.Entry<HStoreKey, byte []> es: tailMap.entrySet()) {
HStoreKey itKey = es.getKey();
Text itCol = itKey.getColumn();
if (results.get(itCol) == null && key.matchesWithoutColumn(itKey)) {
byte [] val = tailMap.get(itKey);
if (HLogEdit.isDeleted(val)) {
if (!deletes.containsKey(itCol)
|| deletes.get(itCol).longValue() < itKey.getTimestamp()) {
deletes.put(new Text(itCol), itKey.getTimestamp());
}
} else if (!(deletes.containsKey(itCol)
&& deletes.get(itCol).longValue() >= itKey.getTimestamp())) {
results.put(new Text(itCol), val);
}
} else if (key.getRow().compareTo(itKey.getRow()) < 0) {
break;
}
}
}
/**
* Find the key that matches <i>row</i> exactly, or the one that immediately
* preceeds it.
*/
void getRowKeyAtOrBefore(final Text row,
SortedMap<HStoreKey, Long> candidateKeys) {
this.lock.readLock().lock();
try {
synchronized (memcache) {
internalGetRowKeyAtOrBefore(memcache, row, candidateKeys);
}
synchronized (snapshot) {
internalGetRowKeyAtOrBefore(snapshot, row, candidateKeys);
}
} finally {
this.lock.readLock().unlock();
}
}
private void internalGetRowKeyAtOrBefore(SortedMap<HStoreKey, byte []> map,
Text key, SortedMap<HStoreKey, Long> candidateKeys) {
HStoreKey strippedKey = null;
// we want the earliest possible to start searching from
HStoreKey search_key = candidateKeys.isEmpty() ?
new HStoreKey(key) : new HStoreKey(candidateKeys.firstKey().getRow());
Iterator<HStoreKey> key_iterator = null;
HStoreKey found_key = null;
// get all the entries that come equal or after our search key
SortedMap<HStoreKey, byte []> tailMap = map.tailMap(search_key);
// if there are items in the tail map, there's either a direct match to
// the search key, or a range of values between the first candidate key
// and the ultimate search key (or the end of the cache)
if (!tailMap.isEmpty() && tailMap.firstKey().getRow().compareTo(key) <= 0) {
key_iterator = tailMap.keySet().iterator();
// keep looking at cells as long as they are no greater than the
// ultimate search key and there's still records left in the map.
do {
found_key = key_iterator.next();
if (found_key.getRow().compareTo(key) <= 0) {
strippedKey = stripTimestamp(found_key);
if (HLogEdit.isDeleted(tailMap.get(found_key))) {
if (candidateKeys.containsKey(strippedKey)) {
long bestCandidateTs =
candidateKeys.get(strippedKey).longValue();
if (bestCandidateTs <= found_key.getTimestamp()) {
candidateKeys.remove(strippedKey);
}
}
} else {
candidateKeys.put(strippedKey,
new Long(found_key.getTimestamp()));
}
}
} while (found_key.getRow().compareTo(key) <= 0
&& key_iterator.hasNext());
} else {
// the tail didn't contain any keys that matched our criteria, or was
// empty. examine all the keys that preceed our splitting point.
SortedMap<HStoreKey, byte []> headMap = map.headMap(search_key);
// if we tried to create a headMap and got an empty map, then there are
// no keys at or before the search key, so we're done.
if (headMap.isEmpty()) {
return;
}
// if there aren't any candidate keys at this point, we need to search
// backwards until we find at least one candidate or run out of headMap.
if (candidateKeys.isEmpty()) {
HStoreKey[] cells =
headMap.keySet().toArray(new HStoreKey[headMap.keySet().size()]);
Text lastRowFound = null;
for(int i = cells.length - 1; i >= 0; i--) {
HStoreKey thisKey = cells[i];
// if the last row we found a candidate key for is different than
// the row of the current candidate, we can stop looking.
if (lastRowFound != null && !lastRowFound.equals(thisKey.getRow())) {
break;
}
// if this isn't a delete, record it as a candidate key. also
// take note of the row of this candidate so that we'll know when
// we cross the row boundary into the previous row.
if (!HLogEdit.isDeleted(headMap.get(thisKey))) {
lastRowFound = thisKey.getRow();
candidateKeys.put(stripTimestamp(thisKey),
new Long(thisKey.getTimestamp()));
}
}
} else {
// if there are already some candidate keys, we only need to consider
// the very last row's worth of keys in the headMap, because any
// smaller acceptable candidate keys would have caused us to start
// our search earlier in the list, and we wouldn't be searching here.
SortedMap<HStoreKey, byte[]> thisRowTailMap =
headMap.tailMap(new HStoreKey(headMap.lastKey().getRow()));
key_iterator = thisRowTailMap.keySet().iterator();
do {
found_key = key_iterator.next();
if (HLogEdit.isDeleted(thisRowTailMap.get(found_key))) {
strippedKey = stripTimestamp(found_key);
if (candidateKeys.containsKey(strippedKey)) {
long bestCandidateTs =
candidateKeys.get(strippedKey).longValue();
if (bestCandidateTs <= found_key.getTimestamp()) {
candidateKeys.remove(strippedKey);
}
}
} else {
candidateKeys.put(stripTimestamp(found_key),
found_key.getTimestamp());
}
} while (key_iterator.hasNext());
}
}
}
/**
* Examine a single map for the desired key.
*
* TODO - This is kinda slow. We need a data structure that allows for
* proximity-searches, not just precise-matches.
*
* @param map
* @param key
* @param numVersions
* @return Ordered list of items found in passed <code>map</code>. If no
* matching values, returns an empty list (does not return null).
*/
private ArrayList<byte []> internalGet(
final SortedMap<HStoreKey, byte []> map, final HStoreKey key,
final int numVersions) {
ArrayList<byte []> result = new ArrayList<byte []>();
// TODO: If get is of a particular version -- numVersions == 1 -- we
// should be able to avoid all of the tailmap creations and iterations
// below.
SortedMap<HStoreKey, byte []> tailMap = map.tailMap(key);
for (Map.Entry<HStoreKey, byte []> es: tailMap.entrySet()) {
HStoreKey itKey = es.getKey();
if (itKey.matchesRowCol(key)) {
if (!HLogEdit.isDeleted(es.getValue())) {
result.add(tailMap.get(itKey));
}
}
if (numVersions > 0 && result.size() >= numVersions) {
break;
}
}
return result;
}
/**
* Get <code>versions</code> keys matching the origin key's
* row/column/timestamp and those of an older vintage
* Default access so can be accessed out of {@link HRegionServer}.
* @param origin Where to start searching.
* @param versions How many versions to return. Pass
* {@link HConstants.ALL_VERSIONS} to retrieve all.
* @return Ordered list of <code>versions</code> keys going from newest back.
* @throws IOException
*/
List<HStoreKey> getKeys(final HStoreKey origin, final int versions) {
this.lock.readLock().lock();
try {
List<HStoreKey> results;
synchronized (memcache) {
results = internalGetKeys(this.memcache, origin, versions);
}
synchronized (snapshot) {
results.addAll(results.size(), internalGetKeys(snapshot, origin,
versions == HConstants.ALL_VERSIONS ? versions :
(versions - results.size())));
}
return results;
} finally {
this.lock.readLock().unlock();
}
}
/*
* @param origin Where to start searching.
* @param versions How many versions to return. Pass
* {@link HConstants.ALL_VERSIONS} to retrieve all.
* @return List of all keys that are of the same row and column and of
* equal or older timestamp. If no keys, returns an empty List. Does not
* return null.
*/
private List<HStoreKey> internalGetKeys(final SortedMap<HStoreKey, byte []> map,
final HStoreKey origin, final int versions) {
List<HStoreKey> result = new ArrayList<HStoreKey>();
SortedMap<HStoreKey, byte []> tailMap = map.tailMap(origin);
for (Map.Entry<HStoreKey, byte []> es: tailMap.entrySet()) {
HStoreKey key = es.getKey();
// if there's no column name, then compare rows and timestamps
if (origin.getColumn().toString().equals("")) {
// if the current and origin row don't match, then we can jump
// out of the loop entirely.
if (!key.getRow().equals(origin.getRow())) {
break;
}
// if the rows match but the timestamp is newer, skip it so we can
// get to the ones we actually want.
if (key.getTimestamp() > origin.getTimestamp()) {
continue;
}
}
else{ // compare rows and columns
// if the key doesn't match the row and column, then we're done, since
// all the cells are ordered.
if (!key.matchesRowCol(origin)) {
break;
}
}
if (!HLogEdit.isDeleted(es.getValue())) {
result.add(key);
if (versions != HConstants.ALL_VERSIONS && result.size() >= versions) {
// We have enough results. Return.
break;
}
}
}
return result;
}
/**
* @param key
* @return True if an entry and its content is {@link HGlobals.deleteBytes}.
* Use checking values in store. On occasion the memcache has the fact that
* the cell has been deleted.
*/
boolean isDeleted(final HStoreKey key) {
return HLogEdit.isDeleted(this.memcache.get(key));
}
/**
* @return a scanner over the keys in the Memcache
*/
HInternalScannerInterface getScanner(long timestamp,
Text targetCols[], Text firstRow) throws IOException {
// Here we rely on ReentrantReadWriteLock's ability to acquire multiple
// locks by the same thread and to be able to downgrade a write lock to
// a read lock. We need to hold a lock throughout this method, but only
// need the write lock while creating the memcache snapshot
this.lock.writeLock().lock(); // hold write lock during memcache snapshot
snapshot(); // snapshot memcache
this.lock.readLock().lock(); // acquire read lock
this.lock.writeLock().unlock(); // downgrade to read lock
try {
// Prevent a cache flush while we are constructing the scanner
return new MemcacheScanner(timestamp, targetCols, firstRow);
} finally {
this.lock.readLock().unlock();
}
}
//////////////////////////////////////////////////////////////////////////////
// MemcacheScanner implements the HScannerInterface.
// It lets the caller scan the contents of the Memcache.
//////////////////////////////////////////////////////////////////////////////
class MemcacheScanner extends HAbstractScanner {
SortedMap<HStoreKey, byte []> backingMap;
Iterator<HStoreKey> keyIterator;
@SuppressWarnings("unchecked")
MemcacheScanner(final long timestamp, final Text targetCols[],
final Text firstRow) throws IOException {
super(timestamp, targetCols);
try {
this.backingMap = new TreeMap<HStoreKey, byte[]>();
this.backingMap.putAll(snapshot);
this.keys = new HStoreKey[1];
this.vals = new byte[1][];
// Generate list of iterators
HStoreKey firstKey = new HStoreKey(firstRow);
if (firstRow != null && firstRow.getLength() != 0) {
keyIterator =
backingMap.tailMap(firstKey).keySet().iterator();
} else {
keyIterator = backingMap.keySet().iterator();
}
while (getNext(0)) {
if (!findFirstRow(0, firstRow)) {
continue;
}
if (columnMatch(0)) {
break;
}
}
} catch (RuntimeException ex) {
LOG.error("error initializing Memcache scanner: ", ex);
close();
IOException e = new IOException("error initializing Memcache scanner");
e.initCause(ex);
throw e;
} catch(IOException ex) {
LOG.error("error initializing Memcache scanner: ", ex);
close();
throw ex;
}
}
/**
* The user didn't want to start scanning at the first row. This method
* seeks to the requested row.
*
* @param i which iterator to advance
* @param firstRow seek to this row
* @return true if this is the first row
*/
@Override
boolean findFirstRow(int i, Text firstRow) {
return firstRow.getLength() == 0 ||
keys[i].getRow().compareTo(firstRow) >= 0;
}
/**
* Get the next value from the specified iterator.
*
* @param i Which iterator to fetch next value from
* @return true if there is more data available
*/
@Override
boolean getNext(int i) {
boolean result = false;
while (true) {
if (!keyIterator.hasNext()) {
closeSubScanner(i);
break;
}
// Check key is < than passed timestamp for this scanner.
HStoreKey hsk = keyIterator.next();
if (hsk == null) {
throw new NullPointerException("Unexpected null key");
}
if (hsk.getTimestamp() <= this.timestamp) {
this.keys[i] = hsk;
this.vals[i] = backingMap.get(keys[i]);
result = true;
break;
}
}
return result;
}
/** Shut down an individual map iterator. */
@Override
void closeSubScanner(int i) {
keyIterator = null;
keys[i] = null;
vals[i] = null;
backingMap = null;
}
/** Shut down map iterators */
public void close() {
if (!scannerClosed) {
if(keyIterator != null) {
closeSubScanner(0);
}
scannerClosed = true;
}
}
}
}
/*
* Regex that will work for straight filenames and for reference names.
* If reference, then the regex has more than just one group. Group 1 is
* this files id. Group 2 the referenced region name, etc.
*/
private static Pattern REF_NAME_PARSER =
Pattern.compile("^(\\d+)(?:\\.(.+))?$");
private static final String BLOOMFILTER_FILE_NAME = "filter";
final Memcache memcache = new Memcache();
private final Path basedir;
private final HRegionInfo info;
private final HColumnDescriptor family;
private final SequenceFile.CompressionType compression;
final FileSystem fs;
private final HBaseConfiguration conf;
private final Path filterDir;
final Filter bloomFilter;
private final Path compactionDir;
private final Integer compactLock = new Integer(0);
private final Integer flushLock = new Integer(0);
private final ReentrantReadWriteLock lock = new ReentrantReadWriteLock();
final AtomicInteger activeScanners = new AtomicInteger(0);
final String storeName;
/*
* Sorted Map of readers keyed by sequence id (Most recent should be last in
* in list).
*/
final SortedMap<Long, HStoreFile> storefiles =
Collections.synchronizedSortedMap(new TreeMap<Long, HStoreFile>());
/*
* Sorted Map of readers keyed by sequence id (Most recent should be last in
* in list).
*/
private final SortedMap<Long, MapFile.Reader> readers =
new TreeMap<Long, MapFile.Reader>();
private volatile long maxSeqId;
private final int compactionThreshold;
private final ReentrantReadWriteLock newScannerLock =
new ReentrantReadWriteLock();
/**
* An HStore is a set of zero or more MapFiles, which stretch backwards over
* time. A given HStore is responsible for a certain set of columns for a
* row in the HRegion.
*
* <p>The HRegion starts writing to its set of HStores when the HRegion's
* memcache is flushed. This results in a round of new MapFiles, one for
* each HStore.
*
* <p>There's no reason to consider append-logging at this level; all logging
* and locking is handled at the HRegion level. HStore just provides
* services to manage sets of MapFiles. One of the most important of those
* services is MapFile-compaction services.
*
* <p>The only thing having to do with logs that HStore needs to deal with is
* the reconstructionLog. This is a segment of an HRegion's log that might
* NOT be present upon startup. If the param is NULL, there's nothing to do.
* If the param is non-NULL, we need to process the log to reconstruct
* a TreeMap that might not have been written to disk before the process
* died.
*
* <p>It's assumed that after this constructor returns, the reconstructionLog
* file will be deleted (by whoever has instantiated the HStore).
*
* @param basedir qualified path under which the region directory lives
* @param info HRegionInfo for this region
* @param family HColumnDescriptor for this column
* @param fs file system object
* @param reconstructionLog existing log file to apply if any
* @param conf configuration object
* @throws IOException
*/
HStore(Path basedir, HRegionInfo info, HColumnDescriptor family,
FileSystem fs, Path reconstructionLog, HBaseConfiguration conf)
throws IOException {
this.basedir = basedir;
this.info = info;
this.family = family;
this.fs = fs;
this.conf = conf;
this.compactionDir = HRegion.getCompactionDir(basedir);
this.storeName =
this.info.getEncodedName() + "/" + this.family.getFamilyName();
if (family.getCompression() == HColumnDescriptor.CompressionType.BLOCK) {
this.compression = SequenceFile.CompressionType.BLOCK;
} else if (family.getCompression() ==
HColumnDescriptor.CompressionType.RECORD) {
this.compression = SequenceFile.CompressionType.RECORD;
} else {
this.compression = SequenceFile.CompressionType.NONE;
}
Path mapdir = HStoreFile.getMapDir(basedir, info.getEncodedName(),
family.getFamilyName());
if (!fs.exists(mapdir)) {
fs.mkdirs(mapdir);
}
Path infodir = HStoreFile.getInfoDir(basedir, info.getEncodedName(),
family.getFamilyName());
if (!fs.exists(infodir)) {
fs.mkdirs(infodir);
}
if(family.getBloomFilter() == null) {
this.filterDir = null;
this.bloomFilter = null;
} else {
this.filterDir = HStoreFile.getFilterDir(basedir, info.getEncodedName(),
family.getFamilyName());
if (!fs.exists(filterDir)) {
fs.mkdirs(filterDir);
}
this.bloomFilter = loadOrCreateBloomFilter();
}
if(LOG.isDebugEnabled()) {
LOG.debug("starting " + storeName +
((reconstructionLog == null || !fs.exists(reconstructionLog)) ?
" (no reconstruction log)" :
" with reconstruction log: " + reconstructionLog.toString()));
}
// Go through the 'mapdir' and 'infodir' together, make sure that all
// MapFiles are in a reliable state. Every entry in 'mapdir' must have a
// corresponding one in 'loginfodir'. Without a corresponding log info
// file, the entry in 'mapdir' must be deleted.
List<HStoreFile> hstoreFiles = loadHStoreFiles(infodir, mapdir);
for(HStoreFile hsf: hstoreFiles) {
this.storefiles.put(Long.valueOf(hsf.loadInfo(fs)), hsf);
}
// Now go through all the HSTORE_LOGINFOFILEs and figure out the
// most-recent log-seq-ID that's present. The most-recent such ID means we
// can ignore all log messages up to and including that ID (because they're
// already reflected in the TreeMaps).
//
// If the HSTORE_LOGINFOFILE doesn't contain a number, just ignore it. That
// means it was built prior to the previous run of HStore, and so it cannot
// contain any updates also contained in the log.
this.maxSeqId = getMaxSequenceId(hstoreFiles);
if (LOG.isDebugEnabled()) {
LOG.debug("maximum sequence id for hstore " + storeName + " is " +
this.maxSeqId);
}
doReconstructionLog(reconstructionLog, maxSeqId);
// By default, we compact if an HStore has more than
// MIN_COMMITS_FOR_COMPACTION map files
this.compactionThreshold =
conf.getInt("hbase.hstore.compactionThreshold", 3);
// We used to compact in here before bringing the store online. Instead
// get it online quick even if it needs compactions so we can start
// taking updates as soon as possible (Once online, can take updates even
// during a compaction).
// Move maxSeqId on by one. Why here? And not in HRegion?
this.maxSeqId += 1;
// Finally, start up all the map readers! (There could be more than one
// since we haven't compacted yet.)
for(Map.Entry<Long, HStoreFile> e: this.storefiles.entrySet()) {
this.readers.put(e.getKey(),
e.getValue().getReader(this.fs, this.bloomFilter));
}
}
/*
* @param hstoreFiles
* @return Maximum sequence number found or -1.
* @throws IOException
*/
private long getMaxSequenceId(final List<HStoreFile> hstoreFiles)
throws IOException {
long maxSeqID = -1;
for (HStoreFile hsf : hstoreFiles) {
long seqid = hsf.loadInfo(fs);
if (seqid > 0) {
if (seqid > maxSeqID) {
maxSeqID = seqid;
}
}
}
return maxSeqID;
}
long getMaxSequenceId() {
return this.maxSeqId;
}
/*
* Read the reconstructionLog to see whether we need to build a brand-new
* MapFile out of non-flushed log entries.
*
* We can ignore any log message that has a sequence ID that's equal to or
* lower than maxSeqID. (Because we know such log messages are already
* reflected in the MapFiles.)
*/
private void doReconstructionLog(final Path reconstructionLog,
final long maxSeqID)
throws UnsupportedEncodingException, IOException {
if (reconstructionLog == null || !fs.exists(reconstructionLog)) {
// Nothing to do.
return;
}
long maxSeqIdInLog = -1;
TreeMap<HStoreKey, byte []> reconstructedCache =
new TreeMap<HStoreKey, byte []>();
SequenceFile.Reader logReader = new SequenceFile.Reader(this.fs,
reconstructionLog, this.conf);
try {
HLogKey key = new HLogKey();
HLogEdit val = new HLogEdit();
long skippedEdits = 0;
long editsCount = 0;
while (logReader.next(key, val)) {
maxSeqIdInLog = Math.max(maxSeqIdInLog, key.getLogSeqNum());
if (key.getLogSeqNum() <= maxSeqID) {
skippedEdits++;
continue;
}
// Check this edit is for me. Also, guard against writing
// METACOLUMN info such as HBASE::CACHEFLUSH entries
Text column = val.getColumn();
if (column.equals(HLog.METACOLUMN)
|| !key.getRegionName().equals(info.getRegionName())
|| !HStoreKey.extractFamily(column).equals(family.getFamilyName())) {
continue;
}
HStoreKey k = new HStoreKey(key.getRow(), column, val.getTimestamp());
reconstructedCache.put(k, val.getVal());
editsCount++;
}
if (LOG.isDebugEnabled()) {
LOG.debug("Applied " + editsCount + ", skipped " + skippedEdits +
" because sequence id <= " + maxSeqID);
}
} finally {
logReader.close();
}
if (reconstructedCache.size() > 0) {
// We create a "virtual flush" at maxSeqIdInLog+1.
if (LOG.isDebugEnabled()) {
LOG.debug("flushing reconstructionCache");
}
internalFlushCache(reconstructedCache, maxSeqIdInLog + 1);
}
}
/*
* Creates a series of HStoreFiles loaded from the given directory.
* There must be a matching 'mapdir' and 'loginfo' pair of files.
* If only one exists, we'll delete it.
*
* @param infodir qualified path for info file directory
* @param mapdir qualified path for map file directory
* @throws IOException
*/
private List<HStoreFile> loadHStoreFiles(Path infodir, Path mapdir)
throws IOException {
if (LOG.isDebugEnabled()) {
LOG.debug("infodir: " + infodir.toString() + " mapdir: " +
mapdir.toString());
}
// Look first at info files. If a reference, these contain info we need
// to create the HStoreFile.
Path infofiles[] = fs.listPaths(new Path[] {infodir});
ArrayList<HStoreFile> results = new ArrayList<HStoreFile>(infofiles.length);
ArrayList<Path> mapfiles = new ArrayList<Path>(infofiles.length);
for (Path p: infofiles) {
Matcher m = REF_NAME_PARSER.matcher(p.getName());
/*
* * * * * N O T E * * * * *
*
* We call isReference(Path, Matcher) here because it calls
* Matcher.matches() which must be called before Matcher.group(int)
* and we don't want to call Matcher.matches() twice.
*
* * * * * N O T E * * * * *
*/
boolean isReference = isReference(p, m);
long fid = Long.parseLong(m.group(1));
HStoreFile curfile = null;
HStoreFile.Reference reference = null;
if (isReference) {
reference = readSplitInfo(p, fs);
}
curfile = new HStoreFile(conf, fs, basedir, info.getEncodedName(),
family.getFamilyName(), fid, reference);
Path mapfile = curfile.getMapFilePath();
if (!fs.exists(mapfile)) {
fs.delete(curfile.getInfoFilePath());
LOG.warn("Mapfile " + mapfile.toString() + " does not exist. " +
"Cleaned up info file. Continuing...");
continue;
}
// TODO: Confirm referent exists.
// Found map and sympathetic info file. Add this hstorefile to result.
results.add(curfile);
// Keep list of sympathetic data mapfiles for cleaning info dir in next
// section. Make sure path is fully qualified for compare.
mapfiles.add(mapfile);
}
// List paths by experience returns fully qualified names -- at least when
// running on a mini hdfs cluster.
Path datfiles[] = fs.listPaths(new Path[] {mapdir});
for (int i = 0; i < datfiles.length; i++) {
// If does not have sympathetic info file, delete.
if (!mapfiles.contains(fs.makeQualified(datfiles[i]))) {
fs.delete(datfiles[i]);
}
}
return results;
}
//////////////////////////////////////////////////////////////////////////////
// Bloom filters
//////////////////////////////////////////////////////////////////////////////
/**
* Called by constructor if a bloom filter is enabled for this column family.
* If the HStore already exists, it will read in the bloom filter saved
* previously. Otherwise, it will create a new bloom filter.
*/
private Filter loadOrCreateBloomFilter() throws IOException {
Path filterFile = new Path(filterDir, BLOOMFILTER_FILE_NAME);
Filter bloomFilter = null;
if(fs.exists(filterFile)) {
if (LOG.isDebugEnabled()) {
LOG.debug("loading bloom filter for " + this.storeName);
}
BloomFilterDescriptor.BloomFilterType type =
family.getBloomFilter().filterType;
switch(type) {
case BLOOMFILTER:
bloomFilter = new BloomFilter();
break;
case COUNTING_BLOOMFILTER:
bloomFilter = new CountingBloomFilter();
break;
case RETOUCHED_BLOOMFILTER:
bloomFilter = new RetouchedBloomFilter();
break;
default:
throw new IllegalArgumentException("unknown bloom filter type: " +
type);
}
FSDataInputStream in = fs.open(filterFile);
try {
bloomFilter.readFields(in);
} finally {
fs.close();
}
} else {
if (LOG.isDebugEnabled()) {
LOG.debug("creating bloom filter for " + this.storeName);
}
BloomFilterDescriptor.BloomFilterType type =
family.getBloomFilter().filterType;
switch(type) {
case BLOOMFILTER:
bloomFilter = new BloomFilter(family.getBloomFilter().vectorSize,
family.getBloomFilter().nbHash);
break;
case COUNTING_BLOOMFILTER:
bloomFilter =
new CountingBloomFilter(family.getBloomFilter().vectorSize,
family.getBloomFilter().nbHash);
break;
case RETOUCHED_BLOOMFILTER:
bloomFilter =
new RetouchedBloomFilter(family.getBloomFilter().vectorSize,
family.getBloomFilter().nbHash);
}
}
return bloomFilter;
}
/**
* Flushes bloom filter to disk
*
* @throws IOException
*/
private void flushBloomFilter() throws IOException {
if (LOG.isDebugEnabled()) {
LOG.debug("flushing bloom filter for " + this.storeName);
}
FSDataOutputStream out =
fs.create(new Path(filterDir, BLOOMFILTER_FILE_NAME));
try {
bloomFilter.write(out);
} finally {
out.close();
}
if (LOG.isDebugEnabled()) {
LOG.debug("flushed bloom filter for " + this.storeName);
}
}
//////////////////////////////////////////////////////////////////////////////
// End bloom filters
//////////////////////////////////////////////////////////////////////////////
/**
* Adds a value to the memcache
*
* @param key
* @param value
*/
void add(HStoreKey key, byte[] value) {
lock.readLock().lock();
try {
this.memcache.add(key, value);
} finally {
lock.readLock().unlock();
}
}
/**
* Close all the MapFile readers
*
* We don't need to worry about subsequent requests because the HRegion holds
* a write lock that will prevent any more reads or writes.
*
* @throws IOException
*/
List<HStoreFile> close() throws IOException {
ArrayList<HStoreFile> result = null;
this.lock.writeLock().lock();
try {
for (MapFile.Reader reader: this.readers.values()) {
reader.close();
}
this.readers.clear();
result = new ArrayList<HStoreFile>(storefiles.values());
this.storefiles.clear();
LOG.debug("closed " + this.storeName);
return result;
} finally {
this.lock.writeLock().unlock();
}
}
//////////////////////////////////////////////////////////////////////////////
// Flush changes to disk
//////////////////////////////////////////////////////////////////////////////
/**
* Prior to doing a cache flush, we need to snapshot the memcache. Locking is
* handled by the memcache.
*/
void snapshotMemcache() {
this.memcache.snapshot();
}
/**
* Write out a brand-new set of items to the disk.
*
* We should only store key/vals that are appropriate for the data-columns
* stored in this HStore.
*
* Also, we are not expecting any reads of this MapFile just yet.
*
* Return the entire list of HStoreFiles currently used by the HStore.
*
* @param logCacheFlushId flush sequence number
* @throws IOException
*/
void flushCache(final long logCacheFlushId) throws IOException {
internalFlushCache(memcache.getSnapshot(), logCacheFlushId);
}
private void internalFlushCache(SortedMap<HStoreKey, byte []> cache,
long logCacheFlushId) throws IOException {
synchronized(flushLock) {
// A. Write the Maps out to the disk
HStoreFile flushedFile = new HStoreFile(conf, fs, basedir,
info.getEncodedName(), family.getFamilyName(), -1L, null);
String name = flushedFile.toString();
MapFile.Writer out = flushedFile.getWriter(this.fs, this.compression,
this.bloomFilter);
// Here we tried picking up an existing HStoreFile from disk and
// interlacing the memcache flush compacting as we go. The notion was
// that interlacing would take as long as a pure flush with the added
// benefit of having one less file in the store. Experiments showed that
// it takes two to three times the amount of time flushing -- more column
// families makes it so the two timings come closer together -- but it
// also complicates the flush. The code was removed. Needed work picking
// which file to interlace (favor references first, etc.)
//
// Related, looks like 'merging compactions' in BigTable paper interlaces
// a memcache flush. We don't.
int entries = 0;
try {
for (Map.Entry<HStoreKey, byte []> es: cache.entrySet()) {
HStoreKey curkey = es.getKey();
TextSequence f = HStoreKey.extractFamily(curkey.getColumn());
if (f.equals(this.family.getFamilyName())) {
entries++;
out.append(curkey, new ImmutableBytesWritable(es.getValue()));
}
}
} finally {
out.close();
}
// B. Write out the log sequence number that corresponds to this output
// MapFile. The MapFile is current up to and including the log seq num.
flushedFile.writeInfo(fs, logCacheFlushId);
// C. Flush the bloom filter if any
if (bloomFilter != null) {
flushBloomFilter();
}
// D. Finally, make the new MapFile available.
this.lock.writeLock().lock();
try {
Long flushid = Long.valueOf(logCacheFlushId);
// Open the map file reader.
this.readers.put(flushid,
flushedFile.getReader(this.fs, this.bloomFilter));
this.storefiles.put(flushid, flushedFile);
if(LOG.isDebugEnabled()) {
LOG.debug("Added " + name + " with " + entries +
" entries, sequence id " + logCacheFlushId + ", and size " +
StringUtils.humanReadableInt(flushedFile.length()) + " for " +
this.storeName);
}
} finally {
this.lock.writeLock().unlock();
}
return;
}
}
//////////////////////////////////////////////////////////////////////////////
// Compaction
//////////////////////////////////////////////////////////////////////////////
/**
* @return True if this store needs compaction.
*/
boolean needsCompaction() {
return this.storefiles != null &&
(this.storefiles.size() >= this.compactionThreshold || hasReferences());
}
/*
* @return True if this store has references.
*/
private boolean hasReferences() {
if (this.storefiles != null) {
for (HStoreFile hsf: this.storefiles.values()) {
if (hsf.isReference()) {
return true;
}
}
}
return false;
}
/**
* Compact the back-HStores. This method may take some time, so the calling
* thread must be able to block for long periods.
*
* <p>During this time, the HStore can work as usual, getting values from
* MapFiles and writing new MapFiles from the Memcache.
*
* Existing MapFiles are not destroyed until the new compacted TreeMap is
* completely written-out to disk.
*
* The compactLock prevents multiple simultaneous compactions.
* The structureLock prevents us from interfering with other write operations.
*
* We don't want to hold the structureLock for the whole time, as a compact()
* can be lengthy and we want to allow cache-flushes during this period.
* @throws IOException
*
* @return true if compaction completed successfully
*/
boolean compact() throws IOException {
synchronized (compactLock) {
if (LOG.isDebugEnabled()) {
LOG.debug("started compaction of " + storefiles.size() +
" files using " + compactionDir.toString() + " for " +
this.storeName);
}
// Storefiles are keyed by sequence id. The oldest file comes first.
// We need to return out of here a List that has the newest file first.
List<HStoreFile> filesToCompact =
new ArrayList<HStoreFile>(this.storefiles.values());
Collections.reverse(filesToCompact);
if (filesToCompact.size() < 1 ||
(filesToCompact.size() == 1 && !filesToCompact.get(0).isReference())) {
if (LOG.isDebugEnabled()) {
LOG.debug("nothing to compact for " + this.storeName);
}
return false;
}
if (!fs.exists(compactionDir) && !fs.mkdirs(compactionDir)) {
LOG.warn("Mkdir on " + compactionDir.toString() + " failed");
return false;
}
// Step through them, writing to the brand-new MapFile
HStoreFile compactedOutputFile = new HStoreFile(conf, fs,
this.compactionDir, info.getEncodedName(), family.getFamilyName(),
-1L, null);
MapFile.Writer compactedOut = compactedOutputFile.getWriter(this.fs,
this.compression, this.bloomFilter);
try {
compactHStoreFiles(compactedOut, filesToCompact);
} finally {
compactedOut.close();
}
// Now, write out an HSTORE_LOGINFOFILE for the brand-new TreeMap.
// Compute max-sequenceID seen in any of the to-be-compacted TreeMaps.
long maxId = getMaxSequenceId(filesToCompact);
compactedOutputFile.writeInfo(fs, maxId);
// Move the compaction into place.
completeCompaction(filesToCompact, compactedOutputFile);
return true;
}
}
/*
* Compact passed <code>toCompactFiles</code> into <code>compactedOut</code>.
* We create a new set of MapFile.Reader objects so we don't screw up the
* caching associated with the currently-loaded ones. Our iteration-based
* access pattern is practically designed to ruin the cache.
*
* We work by opening a single MapFile.Reader for each file, and iterating
* through them in parallel. We always increment the lowest-ranked one.
* Updates to a single row/column will appear ranked by timestamp. This allows
* us to throw out deleted values or obsolete versions. @param compactedOut
* @param toCompactFiles @throws IOException
*/
private void compactHStoreFiles(final MapFile.Writer compactedOut,
final List<HStoreFile> toCompactFiles) throws IOException {
int size = toCompactFiles.size();
CompactionReader[] rdrs = new CompactionReader[size];
int index = 0;
for (HStoreFile hsf: toCompactFiles) {
try {
rdrs[index++] =
new MapFileCompactionReader(hsf.getReader(fs, bloomFilter));
} catch (IOException e) {
// Add info about which file threw exception. It may not be in the
// exception message so output a message here where we know the
// culprit.
LOG.warn("Failed with " + e.toString() + ": HStoreFile=" +
hsf.toString() + (hsf.isReference()? ", Reference=" +
hsf.getReference().toString() : "") + " for Store=" +
this.storeName);
closeCompactionReaders(rdrs);
throw e;
}
}
try {
HStoreKey[] keys = new HStoreKey[rdrs.length];
ImmutableBytesWritable[] vals = new ImmutableBytesWritable[rdrs.length];
boolean[] done = new boolean[rdrs.length];
for(int i = 0; i < rdrs.length; i++) {
keys[i] = new HStoreKey();
vals[i] = new ImmutableBytesWritable();
done[i] = false;
}
// Now, advance through the readers in order. This will have the
// effect of a run-time sort of the entire dataset.
int numDone = 0;
for(int i = 0; i < rdrs.length; i++) {
rdrs[i].reset();
done[i] = ! rdrs[i].next(keys[i], vals[i]);
if(done[i]) {
numDone++;
}
}
int timesSeen = 0;
Text lastRow = new Text();
Text lastColumn = new Text();
// Map of a row deletes keyed by column with a list of timestamps for value
Map<Text, List<Long>> deletes = null;
while (numDone < done.length) {
// Find the reader with the smallest key. If two files have same key
// but different values -- i.e. one is delete and other is non-delete
// value -- we will find the first, the one that was written later and
// therefore the one whose value should make it out to the compacted
// store file.
int smallestKey = -1;
for(int i = 0; i < rdrs.length; i++) {
if(done[i]) {
continue;
}
if(smallestKey < 0) {
smallestKey = i;
} else {
if(keys[i].compareTo(keys[smallestKey]) < 0) {
smallestKey = i;
}
}
}
// Reflect the current key/val in the output
HStoreKey sk = keys[smallestKey];
if(lastRow.equals(sk.getRow())
&& lastColumn.equals(sk.getColumn())) {
timesSeen++;
} else {
timesSeen = 1;
// We are on to a new row. Create a new deletes list.
deletes = new HashMap<Text, List<Long>>();
}
byte [] value = (vals[smallestKey] == null)?
null: vals[smallestKey].get();
if (!isDeleted(sk, value, false, deletes) &&
timesSeen <= family.getMaxVersions()) {
// Keep old versions until we have maxVersions worth.
// Then just skip them.
if (sk.getRow().getLength() != 0 && sk.getColumn().getLength() != 0) {
// Only write out objects which have a non-zero length key and
// value
compactedOut.append(sk, vals[smallestKey]);
}
}
// Update last-seen items
lastRow.set(sk.getRow());
lastColumn.set(sk.getColumn());
// Advance the smallest key. If that reader's all finished, then
// mark it as done.
if(!rdrs[smallestKey].next(keys[smallestKey],
vals[smallestKey])) {
done[smallestKey] = true;
rdrs[smallestKey].close();
rdrs[smallestKey] = null;
numDone++;
}
}
} finally {
closeCompactionReaders(rdrs);
}
}
private void closeCompactionReaders(final CompactionReader [] rdrs) {
for (int i = 0; i < rdrs.length; i++) {
if (rdrs[i] != null) {
try {
rdrs[i].close();
} catch (IOException e) {
LOG.warn("Exception closing reader for " + this.storeName, e);
}
}
}
}
/** Interface for generic reader for compactions */
interface CompactionReader {
/**
* Closes the reader
* @throws IOException
*/
public void close() throws IOException;
/**
* Get the next key/value pair
*
* @param key
* @param val
* @return true if more data was returned
* @throws IOException
*/
public boolean next(WritableComparable key, Writable val)
throws IOException;
/**
* Resets the reader
* @throws IOException
*/
public void reset() throws IOException;
}
/** A compaction reader for MapFile */
static class MapFileCompactionReader implements CompactionReader {
final MapFile.Reader reader;
MapFileCompactionReader(final MapFile.Reader r) {
this.reader = r;
}
/** {@inheritDoc} */
public void close() throws IOException {
this.reader.close();
}
/** {@inheritDoc} */
public boolean next(WritableComparable key, Writable val)
throws IOException {
return this.reader.next(key, val);
}
/** {@inheritDoc} */
public void reset() throws IOException {
this.reader.reset();
}
}
/*
* Check if this is cell is deleted.
* If a memcache and a deletes, check key does not have an entry filled.
* Otherwise, check value is not the <code>HGlobals.deleteBytes</code> value.
* If passed value IS deleteBytes, then it is added to the passed
* deletes map.
* @param hsk
* @param value
* @param checkMemcache true if the memcache should be consulted
* @param deletes Map keyed by column with a value of timestamp. Can be null.
* If non-null and passed value is HGlobals.deleteBytes, then we add to this
* map.
* @return True if this is a deleted cell. Adds the passed deletes map if
* passed value is HGlobals.deleteBytes.
*/
private boolean isDeleted(final HStoreKey hsk, final byte [] value,
final boolean checkMemcache, final Map<Text, List<Long>> deletes) {
if (checkMemcache && memcache.isDeleted(hsk)) {
return true;
}
List<Long> timestamps =
(deletes == null) ? null: deletes.get(hsk.getColumn());
if (timestamps != null &&
timestamps.contains(Long.valueOf(hsk.getTimestamp()))) {
return true;
}
if (value == null) {
// If a null value, shouldn't be in here. Mark it as deleted cell.
return true;
}
if (!HLogEdit.isDeleted(value)) {
return false;
}
// Cell has delete value. Save it into deletes.
if (deletes != null) {
if (timestamps == null) {
timestamps = new ArrayList<Long>();
deletes.put(hsk.getColumn(), timestamps);
}
// We know its not already in the deletes array else we'd have returned
// earlier so no need to test if timestamps already has this value.
timestamps.add(Long.valueOf(hsk.getTimestamp()));
}
return true;
}
/*
* It's assumed that the compactLock will be acquired prior to calling this
* method! Otherwise, it is not thread-safe!
*
* It works by processing a compaction that's been written to disk.
*
* <p>It is usually invoked at the end of a compaction, but might also be
* invoked at HStore startup, if the prior execution died midway through.
*
* <p>Moving the compacted TreeMap into place means:
* <pre>
* 1) Wait for active scanners to exit
* 2) Acquiring the write-lock
* 3) Figuring out what MapFiles are going to be replaced
* 4) Moving the new compacted MapFile into place
* 5) Unloading all the replaced MapFiles.
* 6) Deleting all the old MapFile files.
* 7) Loading the new TreeMap.
* 8) Releasing the write-lock
* 9) Allow new scanners to proceed.
* </pre>
*
* @param compactedFiles list of files that were compacted
* @param compactedFile HStoreFile that is the result of the compaction
* @throws IOException
*/
private void completeCompaction(List<HStoreFile> compactedFiles,
HStoreFile compactedFile) throws IOException {
// 1. Wait for active scanners to exit
newScannerLock.writeLock().lock(); // prevent new scanners
try {
synchronized (activeScanners) {
while (activeScanners.get() != 0) {
try {
activeScanners.wait();
} catch (InterruptedException e) {
// continue
}
}
// 2. Acquiring the HStore write-lock
this.lock.writeLock().lock();
}
try {
// 3. Moving the new MapFile into place.
HStoreFile finalCompactedFile = new HStoreFile(conf, fs, basedir,
info.getEncodedName(), family.getFamilyName(), -1, null);
if(LOG.isDebugEnabled()) {
LOG.debug("moving " + compactedFile.toString() + " in " +
this.compactionDir.toString() + " to " +
finalCompactedFile.toString() + " in " + basedir.toString() +
" for " + this.storeName);
}
if (!compactedFile.rename(this.fs, finalCompactedFile)) {
LOG.error("Failed move of compacted file " +
finalCompactedFile.toString() + " for " + this.storeName);
return;
}
// 4. and 5. Unload all the replaced MapFiles, close and delete.
List<Long> toDelete = new ArrayList<Long>();
for (Map.Entry<Long, HStoreFile> e: this.storefiles.entrySet()) {
if (!compactedFiles.contains(e.getValue())) {
continue;
}
Long key = e.getKey();
MapFile.Reader reader = this.readers.remove(key);
if (reader != null) {
reader.close();
}
toDelete.add(key);
}
try {
for (Long key: toDelete) {
HStoreFile hsf = this.storefiles.remove(key);
hsf.delete();
}
// 6. Loading the new TreeMap.
Long orderVal = Long.valueOf(finalCompactedFile.loadInfo(fs));
this.readers.put(orderVal,
finalCompactedFile.getReader(this.fs, this.bloomFilter));
this.storefiles.put(orderVal, finalCompactedFile);
} catch (IOException e) {
e = RemoteExceptionHandler.checkIOException(e);
LOG.error("Failed replacing compacted files for " + this.storeName +
". Compacted file is " + finalCompactedFile.toString() +
". Files replaced are " + compactedFiles.toString() +
" some of which may have been already removed", e);
}
} finally {
// 7. Releasing the write-lock
this.lock.writeLock().unlock();
}
} finally {
// 8. Allow new scanners to proceed.
newScannerLock.writeLock().unlock();
}
}
//////////////////////////////////////////////////////////////////////////////
// Accessors.
// (This is the only section that is directly useful!)
//////////////////////////////////////////////////////////////////////////////
/**
* Return all the available columns for the given key. The key indicates a
* row and timestamp, but not a column name.
*
* The returned object should map column names to byte arrays (byte[]).
*/
void getFull(HStoreKey key, TreeMap<Text, byte []> results)
throws IOException {
Map<Text, Long> deletes = new HashMap<Text, Long>();
if (key == null) {
return;
}
this.lock.readLock().lock();
memcache.getFull(key, deletes, results);
try {
MapFile.Reader[] maparray = getReaders();
for (int i = maparray.length - 1; i >= 0; i--) {
MapFile.Reader map = maparray[i];
getFullFromMapFile(map, key, deletes, results);
}
} finally {
this.lock.readLock().unlock();
}
}
private void getFullFromMapFile(MapFile.Reader map, HStoreKey key,
Map<Text, Long> deletes, TreeMap<Text, byte[]> results)
throws IOException {
synchronized(map) {
map.reset();
ImmutableBytesWritable readval = new ImmutableBytesWritable();
HStoreKey readkey = (HStoreKey)map.getClosest(key, readval);
if (readkey == null) {
return;
}
do {
Text readcol = readkey.getColumn();
// if there isn't already a value in the results map, and the key we
// just read matches, then we'll consider it
if (!results.containsKey(readcol) && key.matchesWithoutColumn(readkey)) {
// if the value of the cell we're looking at right now is a delete,
// we need to treat it differently
if(HLogEdit.isDeleted(readval.get())) {
// if it's not already recorded as a delete or recorded with a more
// recent delete timestamp, record it for later
if (!deletes.containsKey(readcol)
|| deletes.get(readcol).longValue() < readkey.getTimestamp()) {
deletes.put(new Text(readcol), readkey.getTimestamp());
}
} else if (!(deletes.containsKey(readcol)
&& deletes.get(readcol).longValue() >= readkey.getTimestamp()) ) {
// So the cell itself isn't a delete, but there may be a delete
// pending from earlier in our search. Only record this result if
// there aren't any pending deletes.
if (!(deletes.containsKey(readcol)
&& deletes.get(readcol).longValue() >= readkey.getTimestamp())) {
results.put(new Text(readcol), readval.get());
// need to reinstantiate the readval so we can reuse it,
// otherwise next iteration will destroy our result
readval = new ImmutableBytesWritable();
}
}
} else if(key.getRow().compareTo(readkey.getRow()) < 0) {
// if we've crossed into the next row, then we can just stop
// iterating
return;
}
} while(map.next(readkey, readval));
}
}
MapFile.Reader [] getReaders() {
return this.readers.values().
toArray(new MapFile.Reader[this.readers.size()]);
}
/**
* Get the value for the indicated HStoreKey. Grab the target value and the
* previous 'numVersions-1' values, as well.
*
* If 'numVersions' is negative, the method returns all available versions.
* @param key
* @param numVersions Number of versions to fetch. Must be > 0.
* @return values for the specified versions
* @throws IOException
*/
byte [][] get(HStoreKey key, int numVersions) throws IOException {
if (numVersions <= 0) {
throw new IllegalArgumentException("Number of versions must be > 0");
}
this.lock.readLock().lock();
try {
// Check the memcache
List<byte[]> results = this.memcache.get(key, numVersions);
// If we got sufficient versions from memcache, return.
if (results.size() == numVersions) {
return ImmutableBytesWritable.toArray(results);
}
// Keep a list of deleted cell keys. We need this because as we go through
// the store files, the cell with the delete marker may be in one file and
// the old non-delete cell value in a later store file. If we don't keep
// around the fact that the cell was deleted in a newer record, we end up
// returning the old value if user is asking for more than one version.
// This List of deletes should not large since we are only keeping rows
// and columns that match those set on the scanner and which have delete
// values. If memory usage becomes an issue, could redo as bloom filter.
Map<Text, List<Long>> deletes = new HashMap<Text, List<Long>>();
// This code below is very close to the body of the getKeys method.
MapFile.Reader[] maparray = getReaders();
for(int i = maparray.length - 1; i >= 0; i--) {
MapFile.Reader map = maparray[i];
synchronized(map) {
map.reset();
ImmutableBytesWritable readval = new ImmutableBytesWritable();
HStoreKey readkey = (HStoreKey)map.getClosest(key, readval);
if (readkey == null) {
// map.getClosest returns null if the passed key is > than the
// last key in the map file. getClosest is a bit of a misnomer
// since it returns exact match or the next closest key AFTER not
// BEFORE.
continue;
}
if (!readkey.matchesRowCol(key)) {
continue;
}
if (!isDeleted(readkey, readval.get(), true, deletes)) {
results.add(readval.get());
// Perhaps only one version is wanted. I could let this
// test happen later in the for loop test but it would cost
// the allocation of an ImmutableBytesWritable.
if (hasEnoughVersions(numVersions, results)) {
break;
}
}
for (readval = new ImmutableBytesWritable();
map.next(readkey, readval) &&
readkey.matchesRowCol(key) &&
!hasEnoughVersions(numVersions, results);
readval = new ImmutableBytesWritable()) {
if (!isDeleted(readkey, readval.get(), true, deletes)) {
results.add(readval.get());
}
}
}
if (hasEnoughVersions(numVersions, results)) {
break;
}
}
return results.size() == 0 ?
null : ImmutableBytesWritable.toArray(results);
} finally {
this.lock.readLock().unlock();
}
}
private boolean hasEnoughVersions(final int numVersions,
final List<byte []> results) {
return numVersions > 0 && results.size() >= numVersions;
}
/**
* Get <code>versions</code> keys matching the origin key's
* row/column/timestamp and those of an older vintage
* Default access so can be accessed out of {@link HRegionServer}.
* @param origin Where to start searching.
* @param versions How many versions to return. Pass
* {@link HConstants.ALL_VERSIONS} to retrieve all. Versions will include
* size of passed <code>allKeys</code> in its count.
* @param allKeys List of keys prepopulated by keys we found in memcache.
* This method returns this passed list with all matching keys found in
* stores appended.
* @return The passed <code>allKeys</code> with <code>versions</code> of
* matching keys found in store files appended.
* @throws IOException
*/
List<HStoreKey> getKeys(final HStoreKey origin, final int versions)
throws IOException {
List<HStoreKey> keys = this.memcache.getKeys(origin, versions);
if (versions != ALL_VERSIONS && keys.size() >= versions) {
return keys;
}
// This code below is very close to the body of the get method.
this.lock.readLock().lock();
try {
MapFile.Reader[] maparray = getReaders();
for(int i = maparray.length - 1; i >= 0; i--) {
MapFile.Reader map = maparray[i];
synchronized(map) {
map.reset();
// do the priming read
ImmutableBytesWritable readval = new ImmutableBytesWritable();
HStoreKey readkey = (HStoreKey)map.getClosest(origin, readval);
if (readkey == null) {
// map.getClosest returns null if the passed key is > than the
// last key in the map file. getClosest is a bit of a misnomer
// since it returns exact match or the next closest key AFTER not
// BEFORE.
continue;
}
do{
// if the row matches, we might want this one.
if(rowMatches(origin, readkey)){
// if the cell matches, then we definitely want this key.
if (cellMatches(origin, readkey)) {
// store the key if it isn't deleted or superceeded by what's
// in the memcache
if (!isDeleted(readkey, readval.get(), false, null) &&
!keys.contains(readkey)) {
keys.add(new HStoreKey(readkey));
// if we've collected enough versions, then exit the loop.
if (versions != ALL_VERSIONS && keys.size() >= versions) {
break;
}
}
} else {
// the cell doesn't match, but there might be more with different
// timestamps, so move to the next key
continue;
}
} else{
// the row doesn't match, so we've gone too far.
break;
}
}while(map.next(readkey, readval)); // advance to the next key
}
}
return keys;
} finally {
this.lock.readLock().unlock();
}
}
/**
* Find the key that matches <i>row</i> exactly, or the one that immediately
* preceeds it. WARNING: Only use this method on a table where writes occur
* with stricly increasing timestamps. This method assumes this pattern of
* writes in order to make it reasonably performant.
*/
Text getRowKeyAtOrBefore(final Text row)
throws IOException{
// map of HStoreKeys that are candidates for holding the row key that
// most closely matches what we're looking for. we'll have to update it
// deletes found all over the place as we go along before finally reading
// the best key out of it at the end.
SortedMap<HStoreKey, Long> candidateKeys = new TreeMap<HStoreKey, Long>();
// obtain read lock
this.lock.readLock().lock();
try {
MapFile.Reader[] maparray = getReaders();
// process each store file
for(int i = maparray.length - 1; i >= 0; i--) {
// update the candidate keys from the current map file
rowAtOrBeforeFromMapFile(maparray[i], row, candidateKeys);
}
// finally, check the memcache
memcache.getRowKeyAtOrBefore(row, candidateKeys);
// return the best key from candidateKeys
if (!candidateKeys.isEmpty()) {
return candidateKeys.lastKey().getRow();
}
return null;
} finally {
this.lock.readLock().unlock();
}
}
/**
* Check an individual MapFile for the row at or before a given key
* and timestamp
*/
private void rowAtOrBeforeFromMapFile(MapFile.Reader map, Text row,
SortedMap<HStoreKey, Long> candidateKeys)
throws IOException {
HStoreKey searchKey = null;
ImmutableBytesWritable readval = new ImmutableBytesWritable();
HStoreKey readkey = new HStoreKey();
synchronized(map) {
// don't bother with the rest of this if the file is empty
map.reset();
if (!map.next(readkey, readval)) {
return;
}
// if there aren't any candidate keys yet, we'll do some things slightly
// different
if (candidateKeys.isEmpty()) {
searchKey = new HStoreKey(row);
// if the row we're looking for is past the end of this mapfile, just
// save time and add the last key to the candidates.
HStoreKey finalKey = new HStoreKey();
map.finalKey(finalKey);
if (finalKey.getRow().compareTo(row) < 0) {
candidateKeys.put(stripTimestamp(finalKey),
new Long(finalKey.getTimestamp()));
return;
}
// seek to the exact row, or the one that would be immediately before it
readkey = (HStoreKey)map.getClosest(searchKey, readval, true);
if (readkey == null) {
// didn't find anything that would match, so return
return;
}
do {
// if we have an exact match on row, and it's not a delete, save this
// as a candidate key
if (readkey.getRow().equals(row)) {
if (!HLogEdit.isDeleted(readval.get())) {
candidateKeys.put(stripTimestamp(readkey),
new Long(readkey.getTimestamp()));
}
} else if (readkey.getRow().compareTo(row) > 0 ) {
// if the row key we just read is beyond the key we're searching for,
// then we're done. return.
return;
} else {
// so, the row key doesn't match, but we haven't gone past the row
// we're seeking yet, so this row is a candidate for closest
// (assuming that it isn't a delete).
if (!HLogEdit.isDeleted(readval.get())) {
candidateKeys.put(stripTimestamp(readkey),
new Long(readkey.getTimestamp()));
}
}
} while(map.next(readkey, readval));
// arriving here just means that we consumed the whole rest of the map
// without going "past" the key we're searching for. we can just fall
// through here.
} else {
// if there are already candidate keys, we need to start our search
// at the earliest possible key so that we can discover any possible
// deletes for keys between the start and the search key.
searchKey = new HStoreKey(candidateKeys.firstKey().getRow());
HStoreKey strippedKey = null;
// if the row we're looking for is past the end of this mapfile, just
// save time and add the last key to the candidates.
HStoreKey finalKey = new HStoreKey();
map.finalKey(finalKey);
if (finalKey.getRow().compareTo(searchKey.getRow()) < 0) {
strippedKey = stripTimestamp(finalKey);
// if the candidate keys has a cell like this one already,
// then we might want to update the timestamp we're using on it
if (candidateKeys.containsKey(strippedKey)) {
long bestCandidateTs =
candidateKeys.get(strippedKey).longValue();
if (bestCandidateTs < finalKey.getTimestamp()) {
candidateKeys.put(strippedKey, new Long(finalKey.getTimestamp()));
}
} else {
// otherwise, this is a new key, so put it up as a candidate
candidateKeys.put(strippedKey, new Long(finalKey.getTimestamp()));
}
return;
}
// seek to the exact row, or the one that would be immediately before it
readkey = (HStoreKey)map.getClosest(searchKey, readval, true);
if (readkey == null) {
// didn't find anything that would match, so return
return;
}
do {
// if we have an exact match on row, and it's not a delete, save this
// as a candidate key
if (readkey.getRow().equals(row)) {
strippedKey = stripTimestamp(readkey);
if (!HLogEdit.isDeleted(readval.get())) {
candidateKeys.put(strippedKey, new Long(readkey.getTimestamp()));
} else {
// if the candidate keys contain any that might match by timestamp,
// then check for a match and remove it if it's too young to
// survive the delete
if (candidateKeys.containsKey(strippedKey)) {
long bestCandidateTs =
candidateKeys.get(strippedKey).longValue();
if (bestCandidateTs <= readkey.getTimestamp()) {
candidateKeys.remove(strippedKey);
}
}
}
} else if (readkey.getRow().compareTo(row) > 0 ) {
// if the row key we just read is beyond the key we're searching for,
// then we're done. return.
return;
} else {
strippedKey = stripTimestamp(readkey);
// so, the row key doesn't match, but we haven't gone past the row
// we're seeking yet, so this row is a candidate for closest
// (assuming that it isn't a delete).
if (!HLogEdit.isDeleted(readval.get())) {
candidateKeys.put(strippedKey, readkey.getTimestamp());
} else {
// if the candidate keys contain any that might match by timestamp,
// then check for a match and remove it if it's too young to
// survive the delete
if (candidateKeys.containsKey(strippedKey)) {
long bestCandidateTs =
candidateKeys.get(strippedKey).longValue();
if (bestCandidateTs <= readkey.getTimestamp()) {
candidateKeys.remove(strippedKey);
}
}
}
}
} while(map.next(readkey, readval));
}
}
}
static HStoreKey stripTimestamp(HStoreKey key) {
return new HStoreKey(key.getRow(), key.getColumn());
}
/**
* Test that the <i>target</i> matches the <i>origin</i>. If the
* <i>origin</i> has an empty column, then it's assumed to mean any column
* matches and only match on row and timestamp. Otherwise, it compares the
* keys with HStoreKey.matchesRowCol().
* @param origin The key we're testing against
* @param target The key we're testing
*/
private boolean cellMatches(HStoreKey origin, HStoreKey target){
// if the origin's column is empty, then we're matching any column
if (origin.getColumn().equals(new Text())){
// if the row matches, then...
if (target.getRow().equals(origin.getRow())) {
// check the timestamp
return target.getTimestamp() <= origin.getTimestamp();
}
return false;
}
// otherwise, we want to match on row and column
return target.matchesRowCol(origin);
}
/**
* Test that the <i>target</i> matches the <i>origin</i>. If the <i>origin</i>
* has an empty column, then it just tests row equivalence. Otherwise, it uses
* HStoreKey.matchesRowCol().
* @param origin Key we're testing against
* @param target Key we're testing
*/
private boolean rowMatches(HStoreKey origin, HStoreKey target){
// if the origin's column is empty, then we're matching any column
if (origin.getColumn().equals(new Text())){
// if the row matches, then...
return target.getRow().equals(origin.getRow());
}
// otherwise, we want to match on row and column
return target.matchesRowCol(origin);
}
/*
* Data structure to hold result of a look at store file sizes.
*/
static class HStoreSize {
final long aggregate;
final long largest;
boolean splitable;
HStoreSize(final long a, final long l, final boolean s) {
this.aggregate = a;
this.largest = l;
this.splitable = s;
}
long getAggregate() {
return this.aggregate;
}
long getLargest() {
return this.largest;
}
boolean isSplitable() {
return this.splitable;
}
void setSplitable(final boolean s) {
this.splitable = s;
}
}
/**
* Gets size for the store.
*
* @param midKey Gets set to the middle key of the largest splitable store
* file or its set to empty if largest is not splitable.
* @return Sizes for the store and the passed <code>midKey</code> is
* set to midKey of largest splitable. Otherwise, its set to empty
* to indicate we couldn't find a midkey to split on
*/
HStoreSize size(Text midKey) {
long maxSize = 0L;
long aggregateSize = 0L;
// Not splitable if we find a reference store file present in the store.
boolean splitable = true;
if (this.storefiles.size() <= 0) {
return new HStoreSize(0, 0, splitable);
}
this.lock.readLock().lock();
try {
Long mapIndex = Long.valueOf(0L);
// Iterate through all the MapFiles
for (Map.Entry<Long, HStoreFile> e: storefiles.entrySet()) {
HStoreFile curHSF = e.getValue();
long size = curHSF.length();
aggregateSize += size;
if (maxSize == 0L || size > maxSize) {
// This is the largest one so far
maxSize = size;
mapIndex = e.getKey();
}
if (splitable) {
splitable = !curHSF.isReference();
}
}
if (splitable) {
MapFile.Reader r = this.readers.get(mapIndex);
// seek back to the beginning of mapfile
r.reset();
// get the first and last keys
HStoreKey firstKey = new HStoreKey();
HStoreKey lastKey = new HStoreKey();
Writable value = new ImmutableBytesWritable();
r.next(firstKey, value);
r.finalKey(lastKey);
// get the midkey
HStoreKey mk = (HStoreKey)r.midKey();
if (mk != null) {
// if the midkey is the same as the first and last keys, then we cannot
// (ever) split this region.
if (mk.getRow().equals(firstKey.getRow()) &&
mk.getRow().equals(lastKey.getRow())) {
return new HStoreSize(aggregateSize, maxSize, false);
}
// Otherwise, set midKey
midKey.set(mk.getRow());
}
}
} catch(IOException e) {
LOG.warn("Failed getting store size for " + this.storeName, e);
} finally {
this.lock.readLock().unlock();
}
return new HStoreSize(aggregateSize, maxSize, splitable);
}
//////////////////////////////////////////////////////////////////////////////
// File administration
//////////////////////////////////////////////////////////////////////////////
/**
* Return a scanner for both the memcache and the HStore files
*/
HInternalScannerInterface getScanner(long timestamp, Text targetCols[],
Text firstRow, RowFilterInterface filter) throws IOException {
newScannerLock.readLock().lock(); // ability to create a new
// scanner during a compaction
try {
lock.readLock().lock(); // lock HStore
try {
return new HStoreScanner(targetCols, firstRow, timestamp, filter);
} finally {
lock.readLock().unlock();
}
} finally {
newScannerLock.readLock().unlock();
}
}
/** {@inheritDoc} */
@Override
public String toString() {
return this.storeName;
}
/*
* @see writeSplitInfo(Path p, HStoreFile hsf, FileSystem fs)
*/
static HStoreFile.Reference readSplitInfo(final Path p, final FileSystem fs)
throws IOException {
FSDataInputStream in = fs.open(p);
try {
HStoreFile.Reference r = new HStoreFile.Reference();
r.readFields(in);
return r;
} finally {
in.close();
}
}
/**
* @param p Path to check.
* @return True if the path has format of a HStoreFile reference.
*/
public static boolean isReference(final Path p) {
return isReference(p, REF_NAME_PARSER.matcher(p.getName()));
}
private static boolean isReference(final Path p, final Matcher m) {
if (m == null || !m.matches()) {
LOG.warn("Failed match of store file name " + p.toString());
throw new RuntimeException("Failed match of store file name " +
p.toString());
}
return m.groupCount() > 1 && m.group(2) != null;
}
/**
* A scanner that iterates through the HStore files
*/
private class StoreFileScanner extends HAbstractScanner {
@SuppressWarnings("hiding")
private MapFile.Reader[] readers;
StoreFileScanner(long timestamp, Text[] targetCols, Text firstRow)
throws IOException {
super(timestamp, targetCols);
try {
this.readers = new MapFile.Reader[storefiles.size()];
// Most recent map file should be first
int i = readers.length - 1;
for(HStoreFile curHSF: storefiles.values()) {
readers[i--] = curHSF.getReader(fs, bloomFilter);
}
this.keys = new HStoreKey[readers.length];
this.vals = new byte[readers.length][];
// Advance the readers to the first pos.
for(i = 0; i < readers.length; i++) {
keys[i] = new HStoreKey();
if(firstRow.getLength() != 0) {
if(findFirstRow(i, firstRow)) {
continue;
}
}
while(getNext(i)) {
if(columnMatch(i)) {
break;
}
}
}
} catch (Exception ex) {
close();
IOException e = new IOException("HStoreScanner failed construction");
e.initCause(ex);
throw e;
}
}
/**
* The user didn't want to start scanning at the first row. This method
* seeks to the requested row.
*
* @param i - which iterator to advance
* @param firstRow - seek to this row
* @return - true if this is the first row or if the row was not found
*/
@Override
boolean findFirstRow(int i, Text firstRow) throws IOException {
ImmutableBytesWritable ibw = new ImmutableBytesWritable();
HStoreKey firstKey
= (HStoreKey)readers[i].getClosest(new HStoreKey(firstRow), ibw);
if (firstKey == null) {
// Didn't find it. Close the scanner and return TRUE
closeSubScanner(i);
return true;
}
this.vals[i] = ibw.get();
keys[i].setRow(firstKey.getRow());
keys[i].setColumn(firstKey.getColumn());
keys[i].setVersion(firstKey.getTimestamp());
return columnMatch(i);
}
/**
* Get the next value from the specified reader.
*
* @param i - which reader to fetch next value from
* @return - true if there is more data available
*/
@Override
boolean getNext(int i) throws IOException {
boolean result = false;
ImmutableBytesWritable ibw = new ImmutableBytesWritable();
while (true) {
if (!readers[i].next(keys[i], ibw)) {
closeSubScanner(i);
break;
}
if (keys[i].getTimestamp() <= this.timestamp) {
vals[i] = ibw.get();
result = true;
break;
}
}
return result;
}
/** Close down the indicated reader. */
@Override
void closeSubScanner(int i) {
try {
if(readers[i] != null) {
try {
readers[i].close();
} catch(IOException e) {
LOG.error(storeName + " closing sub-scanner", e);
}
}
} finally {
readers[i] = null;
keys[i] = null;
vals[i] = null;
}
}
/** Shut it down! */
public void close() {
if(! scannerClosed) {
try {
for(int i = 0; i < readers.length; i++) {
if(readers[i] != null) {
try {
readers[i].close();
} catch(IOException e) {
LOG.error(storeName + " closing scanner", e);
}
}
}
} finally {
scannerClosed = true;
}
}
}
}
/**
* Scanner scans both the memcache and the HStore
*/
private class HStoreScanner implements HInternalScannerInterface {
private HInternalScannerInterface[] scanners;
private TreeMap<Text, byte []>[] resultSets;
private HStoreKey[] keys;
private boolean wildcardMatch = false;
private boolean multipleMatchers = false;
private RowFilterInterface dataFilter;
/** Create an Scanner with a handle on the memcache and HStore files. */
@SuppressWarnings("unchecked")
HStoreScanner(Text[] targetCols, Text firstRow, long timestamp,
RowFilterInterface filter) throws IOException {
this.dataFilter = filter;
if (null != dataFilter) {
dataFilter.reset();
}
this.scanners = new HInternalScannerInterface[2];
this.resultSets = new TreeMap[scanners.length];
this.keys = new HStoreKey[scanners.length];
try {
scanners[0] = memcache.getScanner(timestamp, targetCols, firstRow);
scanners[1] = new StoreFileScanner(timestamp, targetCols, firstRow);
for (int i = 0; i < scanners.length; i++) {
if (scanners[i].isWildcardScanner()) {
this.wildcardMatch = true;
}
if (scanners[i].isMultipleMatchScanner()) {
this.multipleMatchers = true;
}
}
} catch(IOException e) {
for (int i = 0; i < this.scanners.length; i++) {
if(scanners[i] != null) {
closeScanner(i);
}
}
throw e;
}
// Advance to the first key in each scanner.
// All results will match the required column-set and scanTime.
for (int i = 0; i < scanners.length; i++) {
keys[i] = new HStoreKey();
resultSets[i] = new TreeMap<Text, byte []>();
if(scanners[i] != null && !scanners[i].next(keys[i], resultSets[i])) {
closeScanner(i);
}
}
// As we have now successfully completed initialization, increment the
// activeScanner count.
activeScanners.incrementAndGet();
}
/** @return true if the scanner is a wild card scanner */
public boolean isWildcardScanner() {
return wildcardMatch;
}
/** @return true if the scanner is a multiple match scanner */
public boolean isMultipleMatchScanner() {
return multipleMatchers;
}
/** {@inheritDoc} */
public boolean next(HStoreKey key, SortedMap<Text, byte[]> results)
throws IOException {
// Filtered flag is set by filters. If a cell has been 'filtered out'
// -- i.e. it is not to be returned to the caller -- the flag is 'true'.
boolean filtered = true;
boolean moreToFollow = true;
while (filtered && moreToFollow) {
// Find the lowest-possible key.
Text chosenRow = null;
long chosenTimestamp = -1;
for (int i = 0; i < this.keys.length; i++) {
if (scanners[i] != null &&
(chosenRow == null ||
(keys[i].getRow().compareTo(chosenRow) < 0) ||
((keys[i].getRow().compareTo(chosenRow) == 0) &&
(keys[i].getTimestamp() > chosenTimestamp)))) {
chosenRow = new Text(keys[i].getRow());
chosenTimestamp = keys[i].getTimestamp();
}
}
// Filter whole row by row key?
filtered = dataFilter != null? dataFilter.filter(chosenRow) : false;
// Store the key and results for each sub-scanner. Merge them as
// appropriate.
if (chosenTimestamp >= 0 && !filtered) {
// Here we are setting the passed in key with current row+timestamp
key.setRow(chosenRow);
key.setVersion(chosenTimestamp);
key.setColumn(HConstants.EMPTY_TEXT);
// Keep list of deleted cell keys within this row. We need this
// because as we go through scanners, the delete record may be in an
// early scanner and then the same record with a non-delete, non-null
// value in a later. Without history of what we've seen, we'll return
// deleted values. This List should not ever grow too large since we
// are only keeping rows and columns that match those set on the
// scanner and which have delete values. If memory usage becomes a
// problem, could redo as bloom filter.
List<HStoreKey> deletes = new ArrayList<HStoreKey>();
for (int i = 0; i < scanners.length && !filtered; i++) {
while ((scanners[i] != null
&& !filtered
&& moreToFollow)
&& (keys[i].getRow().compareTo(chosenRow) == 0)) {
// If we are doing a wild card match or there are multiple
// matchers per column, we need to scan all the older versions of
// this row to pick up the rest of the family members
if (!wildcardMatch
&& !multipleMatchers
&& (keys[i].getTimestamp() != chosenTimestamp)) {
break;
}
// NOTE: We used to do results.putAll(resultSets[i]);
// but this had the effect of overwriting newer
// values with older ones. So now we only insert
// a result if the map does not contain the key.
HStoreKey hsk = new HStoreKey(key.getRow(), EMPTY_TEXT,
key.getTimestamp());
for (Map.Entry<Text, byte[]> e : resultSets[i].entrySet()) {
hsk.setColumn(e.getKey());
if (HLogEdit.isDeleted(e.getValue())) {
if (!deletes.contains(hsk)) {
// Key changes as we cycle the for loop so add a copy to
// the set of deletes.
deletes.add(new HStoreKey(hsk));
}
} else if (!deletes.contains(hsk) &&
!filtered &&
moreToFollow &&
!results.containsKey(e.getKey())) {
if (dataFilter != null) {
// Filter whole row by column data?
filtered =
dataFilter.filter(chosenRow, e.getKey(), e.getValue());
if (filtered) {
results.clear();
break;
}
}
results.put(e.getKey(), e.getValue());
}
}
resultSets[i].clear();
if (!scanners[i].next(keys[i], resultSets[i])) {
closeScanner(i);
}
}
}
}
for (int i = 0; i < scanners.length; i++) {
// If the current scanner is non-null AND has a lower-or-equal
// row label, then its timestamp is bad. We need to advance it.
while ((scanners[i] != null) &&
(keys[i].getRow().compareTo(chosenRow) <= 0)) {
resultSets[i].clear();
if (!scanners[i].next(keys[i], resultSets[i])) {
closeScanner(i);
}
}
}
moreToFollow = chosenTimestamp >= 0;
if (dataFilter != null) {
if (moreToFollow) {
dataFilter.rowProcessed(filtered, chosenRow);
}
if (dataFilter.filterAllRemaining()) {
moreToFollow = false;
}
}
if (results.size() <= 0 && !filtered) {
// There were no results found for this row. Marked it as
// 'filtered'-out otherwise we will not move on to the next row.
filtered = true;
}
}
// If we got no results, then there is no more to follow.
if (results == null || results.size() <= 0) {
moreToFollow = false;
}
// Make sure scanners closed if no more results
if (!moreToFollow) {
for (int i = 0; i < scanners.length; i++) {
if (null != scanners[i]) {
closeScanner(i);
}
}
}
return moreToFollow;
}
/** Shut down a single scanner */
void closeScanner(int i) {
try {
try {
scanners[i].close();
} catch (IOException e) {
LOG.warn(storeName + " failed closing scanner " + i, e);
}
} finally {
scanners[i] = null;
keys[i] = null;
resultSets[i] = null;
}
}
/** {@inheritDoc} */
public void close() {
try {
for(int i = 0; i < scanners.length; i++) {
if(scanners[i] != null) {
closeScanner(i);
}
}
} finally {
synchronized (activeScanners) {
int numberOfScanners = activeScanners.decrementAndGet();
if (numberOfScanners < 0) {
LOG.error(storeName +
" number of active scanners less than zero: " +
numberOfScanners + " resetting to zero");
activeScanners.set(0);
numberOfScanners = 0;
}
if (numberOfScanners == 0) {
activeScanners.notifyAll();
}
}
}
}
/** {@inheritDoc} */
public Iterator<Entry<HStoreKey, SortedMap<Text, byte[]>>> iterator() {
throw new UnsupportedOperationException("Unimplemented serverside. " +
"next(HStoreKey, StortedMap(...) is more efficient");
}
}
}