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org.apache.hadoop.hbase.client.AsyncNonMetaRegionLocator Maven / Gradle / Ivy
/**
* 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.client;
import static org.apache.hadoop.hbase.HConstants.NINES;
import static org.apache.hadoop.hbase.HConstants.ZEROES;
import static org.apache.hadoop.hbase.TableName.META_TABLE_NAME;
import static org.apache.hadoop.hbase.client.AsyncRegionLocatorHelper.canUpdateOnError;
import static org.apache.hadoop.hbase.client.AsyncRegionLocatorHelper.createRegionLocations;
import static org.apache.hadoop.hbase.client.AsyncRegionLocatorHelper.isGood;
import static org.apache.hadoop.hbase.client.AsyncRegionLocatorHelper.mergeRegionLocations;
import static org.apache.hadoop.hbase.client.AsyncRegionLocatorHelper.removeRegionLocation;
import static org.apache.hadoop.hbase.client.ConnectionUtils.createClosestRowAfter;
import static org.apache.hadoop.hbase.client.ConnectionUtils.isEmptyStopRow;
import static org.apache.hadoop.hbase.client.RegionInfo.createRegionName;
import static org.apache.hadoop.hbase.util.Bytes.BYTES_COMPARATOR;
import static org.apache.hadoop.hbase.util.CollectionUtils.computeIfAbsent;
import java.io.IOException;
import java.util.Arrays;
import java.util.HashSet;
import java.util.Iterator;
import java.util.LinkedHashMap;
import java.util.Map;
import java.util.Optional;
import java.util.Set;
import java.util.concurrent.CompletableFuture;
import java.util.concurrent.ConcurrentHashMap;
import java.util.concurrent.ConcurrentMap;
import java.util.concurrent.ConcurrentNavigableMap;
import java.util.concurrent.ConcurrentSkipListMap;
import org.apache.commons.lang3.ObjectUtils;
import org.apache.hadoop.hbase.DoNotRetryIOException;
import org.apache.hadoop.hbase.HBaseIOException;
import org.apache.hadoop.hbase.HConstants;
import org.apache.hadoop.hbase.HRegionLocation;
import org.apache.hadoop.hbase.MetaTableAccessor;
import org.apache.hadoop.hbase.RegionLocations;
import org.apache.hadoop.hbase.TableName;
import org.apache.hadoop.hbase.TableNotFoundException;
import org.apache.hadoop.hbase.client.Scan.ReadType;
import org.apache.hadoop.hbase.util.Bytes;
import org.apache.yetus.audience.InterfaceAudience;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.apache.hbase.thirdparty.com.google.common.annotations.VisibleForTesting;
import org.apache.hbase.thirdparty.com.google.common.base.Objects;
/**
* The asynchronous locator for regions other than meta.
*/
@InterfaceAudience.Private
class AsyncNonMetaRegionLocator {
private static final Logger LOG = LoggerFactory.getLogger(AsyncNonMetaRegionLocator.class);
@VisibleForTesting
static final String MAX_CONCURRENT_LOCATE_REQUEST_PER_TABLE =
"hbase.client.meta.max.concurrent.locate.per.table";
private static final int DEFAULT_MAX_CONCURRENT_LOCATE_REQUEST_PER_TABLE = 8;
@VisibleForTesting
static String LOCATE_PREFETCH_LIMIT = "hbase.client.locate.prefetch.limit";
private static final int DEFAULT_LOCATE_PREFETCH_LIMIT = 10;
private final AsyncConnectionImpl conn;
private final int maxConcurrentLocateRequestPerTable;
private final int locatePrefetchLimit;
private final ConcurrentMap cache = new ConcurrentHashMap<>();
private static final class LocateRequest {
private final byte[] row;
private final RegionLocateType locateType;
public LocateRequest(byte[] row, RegionLocateType locateType) {
this.row = row;
this.locateType = locateType;
}
@Override
public int hashCode() {
return Bytes.hashCode(row) ^ locateType.hashCode();
}
@Override
public boolean equals(Object obj) {
if (obj == null || obj.getClass() != LocateRequest.class) {
return false;
}
LocateRequest that = (LocateRequest) obj;
return locateType.equals(that.locateType) && Bytes.equals(row, that.row);
}
}
private static final class TableCache {
private final ConcurrentNavigableMap cache =
new ConcurrentSkipListMap<>(BYTES_COMPARATOR);
private final Set pendingRequests = new HashSet<>();
private final Map> allRequests =
new LinkedHashMap<>();
public boolean hasQuota(int max) {
return pendingRequests.size() < max;
}
public boolean isPending(LocateRequest req) {
return pendingRequests.contains(req);
}
public void send(LocateRequest req) {
pendingRequests.add(req);
}
public Optional getCandidate() {
return allRequests.keySet().stream().filter(r -> !isPending(r)).findFirst();
}
public void clearCompletedRequests(Optional locations) {
for (Iterator>> iter =
allRequests.entrySet().iterator(); iter.hasNext();) {
Map.Entry> entry = iter.next();
if (tryComplete(entry.getKey(), entry.getValue(), locations)) {
iter.remove();
}
}
}
private boolean tryComplete(LocateRequest req, CompletableFuture future,
Optional locations) {
if (future.isDone()) {
return true;
}
if (!locations.isPresent()) {
return false;
}
RegionLocations locs = locations.get();
HRegionLocation loc = ObjectUtils.firstNonNull(locs.getRegionLocations());
// we should at least have one location available, otherwise the request should fail and
// should not arrive here
assert loc != null;
boolean completed;
if (req.locateType.equals(RegionLocateType.BEFORE)) {
// for locating the row before current row, the common case is to find the previous region
// in reverse scan, so we check the endKey first. In general, the condition should be
// startKey < req.row and endKey >= req.row. Here we split it to endKey == req.row ||
// (endKey > req.row && startKey < req.row). The two conditions are equal since startKey <
// endKey.
int c = Bytes.compareTo(loc.getRegion().getEndKey(), req.row);
completed =
c == 0 || (c > 0 && Bytes.compareTo(loc.getRegion().getStartKey(), req.row) < 0);
} else {
completed = loc.getRegion().containsRow(req.row);
}
if (completed) {
future.complete(locs);
return true;
} else {
return false;
}
}
}
AsyncNonMetaRegionLocator(AsyncConnectionImpl conn) {
this.conn = conn;
this.maxConcurrentLocateRequestPerTable = conn.getConfiguration().getInt(
MAX_CONCURRENT_LOCATE_REQUEST_PER_TABLE, DEFAULT_MAX_CONCURRENT_LOCATE_REQUEST_PER_TABLE);
this.locatePrefetchLimit =
conn.getConfiguration().getInt(LOCATE_PREFETCH_LIMIT, DEFAULT_LOCATE_PREFETCH_LIMIT);
}
private TableCache getTableCache(TableName tableName) {
return computeIfAbsent(cache, tableName, TableCache::new);
}
private boolean isEqual(RegionLocations locs1, RegionLocations locs2) {
HRegionLocation[] locArr1 = locs1.getRegionLocations();
HRegionLocation[] locArr2 = locs2.getRegionLocations();
if (locArr1.length != locArr2.length) {
return false;
}
for (int i = 0; i < locArr1.length; i++) {
// do not need to compare region info
HRegionLocation loc1 = locArr1[i];
HRegionLocation loc2 = locArr2[i];
if (loc1 == null) {
if (loc2 != null) {
return false;
}
} else {
if (loc2 == null) {
return false;
}
if (loc1.getSeqNum() != loc2.getSeqNum()) {
return false;
}
if (Objects.equal(loc1.getServerName(), loc2.getServerName())) {
return false;
}
}
}
return true;
}
// return whether we add this loc to cache
private boolean addToCache(TableCache tableCache, RegionLocations locs) {
LOG.trace("Try adding {} to cache", locs);
byte[] startKey = locs.getDefaultRegionLocation().getRegion().getStartKey();
for (;;) {
RegionLocations oldLocs = tableCache.cache.putIfAbsent(startKey, locs);
if (oldLocs == null) {
return true;
}
RegionLocations mergedLocs = mergeRegionLocations(locs, oldLocs);
if (isEqual(mergedLocs, oldLocs)) {
// the merged one is the same with the old one, give up
LOG.trace("Will not add {} to cache because the old value {} " +
" is newer than us or has the same server name." +
" Maybe it is updated before we replace it", locs, oldLocs);
return false;
}
if (tableCache.cache.replace(startKey, oldLocs, mergedLocs)) {
return true;
}
}
}
private void complete(TableName tableName, LocateRequest req, RegionLocations locs,
Throwable error) {
if (error != null) {
LOG.warn("Failed to locate region in '" + tableName + "', row='" +
Bytes.toStringBinary(req.row) + "', locateType=" + req.locateType, error);
}
Optional toSend = Optional.empty();
TableCache tableCache = getTableCache(tableName);
if (locs != null) {
if (!addToCache(tableCache, locs)) {
// someone is ahead of us.
synchronized (tableCache) {
tableCache.pendingRequests.remove(req);
tableCache.clearCompletedRequests(Optional.empty());
// Remove a complete locate request in a synchronized block, so the table cache must have
// quota to send a candidate request.
toSend = tableCache.getCandidate();
toSend.ifPresent(r -> tableCache.send(r));
}
toSend.ifPresent(r -> locateInMeta(tableName, r));
return;
}
}
synchronized (tableCache) {
tableCache.pendingRequests.remove(req);
if (error instanceof DoNotRetryIOException) {
CompletableFuture future = tableCache.allRequests.remove(req);
if (future != null) {
future.completeExceptionally(error);
}
}
tableCache.clearCompletedRequests(Optional.ofNullable(locs));
// Remove a complete locate request in a synchronized block, so the table cache must have
// quota to send a candidate request.
toSend = tableCache.getCandidate();
toSend.ifPresent(r -> tableCache.send(r));
}
toSend.ifPresent(r -> locateInMeta(tableName, r));
}
// return whether we should stop the scan
private boolean onScanNext(TableName tableName, LocateRequest req, Result result) {
RegionLocations locs = MetaTableAccessor.getRegionLocations(result);
if (LOG.isDebugEnabled()) {
LOG.debug("The fetched location of '{}', row='{}', locateType={} is {}", tableName,
Bytes.toStringBinary(req.row), req.locateType, locs);
}
// the default region location should always be presented when fetching from meta, otherwise
// let's fail the request.
if (locs == null || locs.getDefaultRegionLocation() == null) {
complete(tableName, req, null,
new HBaseIOException(String.format("No location found for '%s', row='%s', locateType=%s",
tableName, Bytes.toStringBinary(req.row), req.locateType)));
return true;
}
HRegionLocation loc = locs.getDefaultRegionLocation();
RegionInfo info = loc.getRegion();
if (info == null) {
complete(tableName, req, null,
new HBaseIOException(String.format("HRegionInfo is null for '%s', row='%s', locateType=%s",
tableName, Bytes.toStringBinary(req.row), req.locateType)));
return true;
}
if (info.isSplitParent()) {
return false;
}
complete(tableName, req, locs, null);
return true;
}
private RegionLocations locateRowInCache(TableCache tableCache, TableName tableName, byte[] row,
int replicaId) {
Map.Entry entry = tableCache.cache.floorEntry(row);
if (entry == null) {
return null;
}
RegionLocations locs = entry.getValue();
HRegionLocation loc = locs.getRegionLocation(replicaId);
if (loc == null) {
return null;
}
byte[] endKey = loc.getRegion().getEndKey();
if (isEmptyStopRow(endKey) || Bytes.compareTo(row, endKey) < 0) {
if (LOG.isTraceEnabled()) {
LOG.trace("Found {} in cache for {}, row='{}', locateType={}, replicaId={}", loc, tableName,
Bytes.toStringBinary(row), RegionLocateType.CURRENT, replicaId);
}
return locs;
} else {
return null;
}
}
private RegionLocations locateRowBeforeInCache(TableCache tableCache, TableName tableName,
byte[] row, int replicaId) {
boolean isEmptyStopRow = isEmptyStopRow(row);
Map.Entry entry =
isEmptyStopRow ? tableCache.cache.lastEntry() : tableCache.cache.lowerEntry(row);
if (entry == null) {
return null;
}
RegionLocations locs = entry.getValue();
HRegionLocation loc = locs.getRegionLocation(replicaId);
if (loc == null) {
return null;
}
if (isEmptyStopRow(loc.getRegion().getEndKey()) ||
(!isEmptyStopRow && Bytes.compareTo(loc.getRegion().getEndKey(), row) >= 0)) {
if (LOG.isTraceEnabled()) {
LOG.trace("Found {} in cache for {}, row='{}', locateType={}, replicaId={}", loc, tableName,
Bytes.toStringBinary(row), RegionLocateType.BEFORE, replicaId);
}
return locs;
} else {
return null;
}
}
private void locateInMeta(TableName tableName, LocateRequest req) {
if (LOG.isTraceEnabled()) {
LOG.trace("Try locate '" + tableName + "', row='" + Bytes.toStringBinary(req.row) +
"', locateType=" + req.locateType + " in meta");
}
byte[] metaStartKey;
if (req.locateType.equals(RegionLocateType.BEFORE)) {
if (isEmptyStopRow(req.row)) {
byte[] binaryTableName = tableName.getName();
metaStartKey = Arrays.copyOf(binaryTableName, binaryTableName.length + 1);
} else {
metaStartKey = createRegionName(tableName, req.row, ZEROES, false);
}
} else {
metaStartKey = createRegionName(tableName, req.row, NINES, false);
}
byte[] metaStopKey =
RegionInfo.createRegionName(tableName, HConstants.EMPTY_START_ROW, "", false);
conn.getTable(META_TABLE_NAME)
.scan(new Scan().withStartRow(metaStartKey).withStopRow(metaStopKey, true)
.addFamily(HConstants.CATALOG_FAMILY).setReversed(true).setCaching(locatePrefetchLimit)
.setReadType(ReadType.PREAD), new AdvancedScanResultConsumer() {
private boolean completeNormally = false;
private boolean tableNotFound = true;
@Override
public void onError(Throwable error) {
complete(tableName, req, null, error);
}
@Override
public void onComplete() {
if (tableNotFound) {
complete(tableName, req, null, new TableNotFoundException(tableName));
} else if (!completeNormally) {
complete(tableName, req, null, new IOException("Unable to find region for '" +
Bytes.toStringBinary(req.row) + "' in " + tableName));
}
}
@Override
public void onNext(Result[] results, ScanController controller) {
if (results.length == 0) {
return;
}
tableNotFound = false;
int i = 0;
for (; i < results.length; i++) {
if (onScanNext(tableName, req, results[i])) {
completeNormally = true;
controller.terminate();
i++;
break;
}
}
// Add the remaining results into cache
if (i < results.length) {
TableCache tableCache = getTableCache(tableName);
for (; i < results.length; i++) {
RegionLocations locs = MetaTableAccessor.getRegionLocations(results[i]);
if (locs == null) {
continue;
}
HRegionLocation loc = locs.getDefaultRegionLocation();
if (loc == null) {
continue;
}
RegionInfo info = loc.getRegion();
if (info == null || info.isOffline() || info.isSplitParent()) {
continue;
}
if (addToCache(tableCache, locs)) {
synchronized (tableCache) {
tableCache.clearCompletedRequests(Optional.of(locs));
}
}
}
}
}
});
}
private RegionLocations locateInCache(TableCache tableCache, TableName tableName, byte[] row,
int replicaId, RegionLocateType locateType) {
return locateType.equals(RegionLocateType.BEFORE)
? locateRowBeforeInCache(tableCache, tableName, row, replicaId)
: locateRowInCache(tableCache, tableName, row, replicaId);
}
// locateToPrevious is true means we will use the start key of a region to locate the region
// placed before it. Used for reverse scan. See the comment of
// AsyncRegionLocator.getPreviousRegionLocation.
private CompletableFuture getRegionLocationsInternal(TableName tableName,
byte[] row, int replicaId, RegionLocateType locateType, boolean reload) {
// AFTER should be convert to CURRENT before calling this method
assert !locateType.equals(RegionLocateType.AFTER);
TableCache tableCache = getTableCache(tableName);
if (!reload) {
RegionLocations locs = locateInCache(tableCache, tableName, row, replicaId, locateType);
if (isGood(locs, replicaId)) {
return CompletableFuture.completedFuture(locs);
}
}
CompletableFuture future;
LocateRequest req;
boolean sendRequest = false;
synchronized (tableCache) {
// check again
if (!reload) {
RegionLocations locs = locateInCache(tableCache, tableName, row, replicaId, locateType);
if (isGood(locs, replicaId)) {
return CompletableFuture.completedFuture(locs);
}
}
req = new LocateRequest(row, locateType);
future = tableCache.allRequests.get(req);
if (future == null) {
future = new CompletableFuture<>();
tableCache.allRequests.put(req, future);
if (tableCache.hasQuota(maxConcurrentLocateRequestPerTable) && !tableCache.isPending(req)) {
tableCache.send(req);
sendRequest = true;
}
}
}
if (sendRequest) {
locateInMeta(tableName, req);
}
return future;
}
CompletableFuture getRegionLocations(TableName tableName, byte[] row,
int replicaId, RegionLocateType locateType, boolean reload) {
// as we know the exact row after us, so we can just create the new row, and use the same
// algorithm to locate it.
if (locateType.equals(RegionLocateType.AFTER)) {
row = createClosestRowAfter(row);
locateType = RegionLocateType.CURRENT;
}
return getRegionLocationsInternal(tableName, row, replicaId, locateType, reload);
}
private void removeLocationFromCache(HRegionLocation loc) {
TableCache tableCache = cache.get(loc.getRegion().getTable());
if (tableCache == null) {
return;
}
byte[] startKey = loc.getRegion().getStartKey();
for (;;) {
RegionLocations oldLocs = tableCache.cache.get(startKey);
HRegionLocation oldLoc = oldLocs.getRegionLocation(loc.getRegion().getReplicaId());
if (!canUpdateOnError(loc, oldLoc)) {
return;
}
RegionLocations newLocs = removeRegionLocation(oldLocs, loc.getRegion().getReplicaId());
if (newLocs == null) {
if (tableCache.cache.remove(startKey, oldLocs)) {
return;
}
} else {
if (tableCache.cache.replace(startKey, oldLocs, newLocs)) {
return;
}
}
}
}
private void addLocationToCache(HRegionLocation loc) {
addToCache(getTableCache(loc.getRegion().getTable()), createRegionLocations(loc));
}
private HRegionLocation getCachedLocation(HRegionLocation loc) {
TableCache tableCache = cache.get(loc.getRegion().getTable());
if (tableCache == null) {
return null;
}
RegionLocations locs = tableCache.cache.get(loc.getRegion().getStartKey());
return locs != null ? locs.getRegionLocation(loc.getRegion().getReplicaId()) : null;
}
void updateCachedLocationOnError(HRegionLocation loc, Throwable exception) {
AsyncRegionLocatorHelper.updateCachedLocationOnError(loc, exception, this::getCachedLocation,
this::addLocationToCache, this::removeLocationFromCache);
}
void clearCache(TableName tableName) {
TableCache tableCache = cache.remove(tableName);
if (tableCache == null) {
return;
}
synchronized (tableCache) {
if (!tableCache.allRequests.isEmpty()) {
IOException error = new IOException("Cache cleared");
tableCache.allRequests.values().forEach(f -> f.completeExceptionally(error));
}
}
}
// only used for testing whether we have cached the location for a region.
@VisibleForTesting
RegionLocations getRegionLocationInCache(TableName tableName, byte[] row) {
TableCache tableCache = cache.get(tableName);
if (tableCache == null) {
return null;
}
return locateRowInCache(tableCache, tableName, row, RegionReplicaUtil.DEFAULT_REPLICA_ID);
}
}
