org.apache.hadoop.hbase.client.AsyncNonMetaRegionLocator Maven / Gradle / Ivy
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* Licensed to the Apache Software Foundation (ASF) under one
* or more contributor license agreements. See the NOTICE file
* distributed with this work for additional information
* regarding copyright ownership. The ASF licenses this file
* to you under the Apache License, Version 2.0 (the
* "License"); you may not use this file except in compliance
* with the License. You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package org.apache.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.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.hadoop.hbase.DoNotRetryIOException;
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;
/**
* 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 {
public final byte[] row;
public 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 {
public final ConcurrentNavigableMap cache =
new ConcurrentSkipListMap<>(BYTES_COMPARATOR);
public final Set pendingRequests = new HashSet<>();
public 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 location) {
for (Iterator>> iter =
allRequests.entrySet().iterator(); iter.hasNext();) {
Map.Entry> entry = iter.next();
if (tryComplete(entry.getKey(), entry.getValue(), location)) {
iter.remove();
}
}
}
private boolean tryComplete(LocateRequest req, CompletableFuture future,
Optional location) {
if (future.isDone()) {
return true;
}
if (!location.isPresent()) {
return false;
}
HRegionLocation loc = location.get();
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(loc);
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 void removeFromCache(HRegionLocation loc) {
TableCache tableCache = cache.get(loc.getRegion().getTable());
if (tableCache == null) {
return;
}
tableCache.cache.computeIfPresent(loc.getRegion().getStartKey(), (k, oldLoc) -> {
if (oldLoc.getSeqNum() > loc.getSeqNum() ||
!oldLoc.getServerName().equals(loc.getServerName())) {
return oldLoc;
}
return null;
});
}
// return whether we add this loc to cache
private boolean addToCache(TableCache tableCache, HRegionLocation loc) {
if (LOG.isTraceEnabled()) {
LOG.trace("Try adding " + loc + " to cache");
}
byte[] startKey = loc.getRegion().getStartKey();
HRegionLocation oldLoc = tableCache.cache.putIfAbsent(startKey, loc);
if (oldLoc == null) {
return true;
}
if (oldLoc.getSeqNum() > loc.getSeqNum() ||
oldLoc.getServerName().equals(loc.getServerName())) {
if (LOG.isTraceEnabled()) {
LOG.trace("Will not add " + loc + " to cache because the old value " + oldLoc +
" is newer than us or has the same server name");
}
return false;
}
return loc == tableCache.cache.compute(startKey, (k, oldValue) -> {
if (oldValue == null || oldValue.getSeqNum() <= loc.getSeqNum()) {
return loc;
}
if (LOG.isTraceEnabled()) {
LOG.trace("Will not add " + loc + " to cache because the old value " + oldValue +
" is newer than us or has the same server name." +
" Maybe it is updated before we replace it");
}
return oldValue;
});
}
@edu.umd.cs.findbugs.annotations.SuppressWarnings(value = "UPM_UNCALLED_PRIVATE_METHOD",
justification = "Called by lambda expression")
private void addToCache(HRegionLocation loc) {
addToCache(getTableCache(loc.getRegion().getTable()), loc);
LOG.trace("Try adding {} to cache", loc);
}
private void complete(TableName tableName, LocateRequest req, HRegionLocation loc,
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 (loc != null) {
if (!addToCache(tableCache, loc)) {
// 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(loc));
// 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);
}
if (locs == null || locs.getDefaultRegionLocation() == null) {
complete(tableName, req, null,
new IOException(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 IOException(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;
}
if (loc.getServerName() == null) {
complete(tableName, req, null,
new IOException(
String.format("No server address listed for region '%s', row='%s', locateType=%s",
info.getRegionNameAsString(), Bytes.toStringBinary(req.row), req.locateType)));
return true;
}
complete(tableName, req, loc, null);
return true;
}
private HRegionLocation locateRowInCache(TableCache tableCache, TableName tableName, byte[] row) {
Map.Entry entry = tableCache.cache.floorEntry(row);
if (entry == null) {
return null;
}
HRegionLocation loc = entry.getValue();
byte[] endKey = loc.getRegion().getEndKey();
if (isEmptyStopRow(endKey) || Bytes.compareTo(row, endKey) < 0) {
if (LOG.isTraceEnabled()) {
LOG.trace("Found " + loc + " in cache for '" + tableName + "', row='" +
Bytes.toStringBinary(row) + "', locateType=" + RegionLocateType.CURRENT);
}
return loc;
} else {
return null;
}
}
private HRegionLocation locateRowBeforeInCache(TableCache tableCache, TableName tableName,
byte[] row) {
boolean isEmptyStopRow = isEmptyStopRow(row);
Map.Entry entry =
isEmptyStopRow ? tableCache.cache.lastEntry() : tableCache.cache.lowerEntry(row);
if (entry == null) {
return null;
}
HRegionLocation loc = entry.getValue();
if (isEmptyStopRow(loc.getRegion().getEndKey()) ||
(!isEmptyStopRow && Bytes.compareTo(loc.getRegion().getEndKey(), row) >= 0)) {
if (LOG.isTraceEnabled()) {
LOG.trace("Found " + loc + " in cache for '" + tableName + "', row='" +
Bytes.toStringBinary(row) + "', locateType=" + RegionLocateType.BEFORE);
}
return loc;
} 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() ||
loc.getServerName() == null) {
continue;
}
if (addToCache(tableCache, loc)) {
synchronized (tableCache) {
tableCache.clearCompletedRequests(Optional.of(loc));
}
}
}
}
}
});
}
private HRegionLocation locateInCache(TableCache tableCache, TableName tableName, byte[] row,
RegionLocateType locateType) {
return locateType.equals(RegionLocateType.BEFORE)
? locateRowBeforeInCache(tableCache, tableName, row)
: locateRowInCache(tableCache, tableName, row);
}
// 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 getRegionLocationInternal(TableName tableName,
byte[] row, 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) {
HRegionLocation loc = locateInCache(tableCache, tableName, row, locateType);
if (loc != null) {
return CompletableFuture.completedFuture(loc);
}
}
CompletableFuture future;
LocateRequest req;
boolean sendRequest = false;
synchronized (tableCache) {
// check again
if (!reload) {
HRegionLocation loc = locateInCache(tableCache, tableName, row, locateType);
if (loc != null) {
return CompletableFuture.completedFuture(loc);
}
}
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 getRegionLocation(TableName tableName, byte[] row,
RegionLocateType locateType, boolean reload) {
if (locateType.equals(RegionLocateType.BEFORE)) {
return getRegionLocationInternal(tableName, row, locateType, reload);
} else {
// 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);
}
return getRegionLocationInternal(tableName, row, RegionLocateType.CURRENT, reload);
}
}
void updateCachedLocation(HRegionLocation loc, Throwable exception) {
AsyncRegionLocator.updateCachedLocation(loc, exception, l -> {
TableCache tableCache = cache.get(l.getRegion().getTable());
if (tableCache == null) {
return null;
}
return tableCache.cache.get(l.getRegion().getStartKey());
}, this::addToCache, this::removeFromCache);
}
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
HRegionLocation getRegionLocationInCache(TableName tableName, byte[] row) {
TableCache tableCache = cache.get(tableName);
if (tableCache == null) {
return null;
}
return locateRowInCache(tableCache, tableName, row);
}
}
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