HBASE-24956 : ConnectionManager#locateRegionInMeta waits for user region lock indef…

hbase-client/src/main/java/org/apache/hadoop/hbase/client/ConnectionConfiguration.java

@@ -63,7 +63,7 @@ public class ConnectionConfiguration {
  // toggle for async/sync prefetch
  private final boolean clientScannerAsyncPrefetch;
 
-  /**
+ /**
  * Constructor
  * @param conf Configuration object
  */
@@ -208,5 +208,4 @@ public boolean isClientScannerAsyncPrefetch() {
  public int getRpcTimeout() {
  return rpcTimeout;
  }
-
 }

hbase-client/src/main/java/org/apache/hadoop/hbase/client/ConnectionImplementation.java

@@ -865,13 +865,15 @@ private RegionLocations locateRegionInMeta(TableName tableName, byte[] row, bool
  }
  // Query the meta region
  long pauseBase = this.pause;
- userRegionLock.lock();
+ takeUserRegionLock();
  try {
- if (useCache) {// re-check cache after get lock
- RegionLocations locations = getCachedLocation(tableName, row);
- if (locations != null && locations.getRegionLocation(replicaId) != null) {
- return locations;
- }
+ // We don't need to check if useCache is enabled or not. Even if useCache is false
+ // we already cleared the cache for this row before acquiring userRegion lock so if this
+ // row is present in cache that means some other thread has populated it while we were
+ // waiting to acquire user region lock.
+ RegionLocations locations = getCachedLocation(tableName, row);
+ if (locations != null && locations.getRegionLocation(replicaId) != null) {
+ return locations;
  }
  if (relocateMeta) {
  relocateRegion(TableName.META_TABLE_NAME, HConstants.EMPTY_START_ROW,
@@ -894,7 +896,7 @@ rpcControllerFactory, getMetaLookupPool(), metaReplicaCallTimeoutScanInMicroSeco
  }
  tableNotFound = false;
  // convert the row result into the HRegionLocation we need!
- RegionLocations locations = MetaTableAccessor.getRegionLocations(regionInfoRow);
+ locations = MetaTableAccessor.getRegionLocations(regionInfoRow);
  if (locations == null || locations.getRegionLocation(replicaId) == null) {
  throw new IOException("RegionInfo null in " + tableName + ", row=" + regionInfoRow);
  }
@@ -970,6 +972,19 @@ rpcControllerFactory, getMetaLookupPool(), metaReplicaCallTimeoutScanInMicroSeco
  }
  }
 
+ void takeUserRegionLock() throws IOException {
+ try {
+ long waitTime = connectionConfig.getMetaOperationTimeout();
+ if (!userRegionLock.tryLock(waitTime, TimeUnit.MILLISECONDS)) {
+ throw new LockTimeoutException("Failed to get user region lock in"
+ + waitTime + " ms. " + " for accessing meta region server.");
+ }
+ } catch (InterruptedException ie) {
+ LOG.error("Interrupted while waiting for a lock", ie);
+ throw ExceptionUtil.asInterrupt(ie);
+ }
+ }
+
  /**
  * Put a newly discovered HRegionLocation into the cache.
  * @param tableName The table name.

hbase-client/src/main/java/org/apache/hadoop/hbase/client/LockTimeoutException.java

@@ -0,0 +1,32 @@
+/**
+ *
+ * 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 org.apache.hadoop.hbase.HBaseIOException;
+import org.apache.yetus.audience.InterfaceAudience;
+
+/*
+ Thrown whenever we are not able to get the lock within the specified wait time.
+ */
+@InterfaceAudience.Public
+public class LockTimeoutException extends HBaseIOException {
+ public LockTimeoutException(String message) {
+ super(message);
+ }
+}

hbase-server/src/test/java/org/apache/hadoop/hbase/client/TestMetaCache.java

@@ -58,6 +58,8 @@
 import org.apache.hadoop.hbase.shaded.protobuf.generated.ClientProtos;
 import org.apache.hadoop.hbase.shaded.protobuf.generated.ClientProtos.GetResponse;
 import org.apache.hadoop.hbase.shaded.protobuf.generated.HBaseProtos;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
 
 @Category({MediumTests.class, ClientTests.class})
 public class TestMetaCache {
@@ -70,8 +72,8 @@ public class TestMetaCache {
  private static final TableName TABLE_NAME = TableName.valueOf("test_table");
  private static final byte[] FAMILY = Bytes.toBytes("fam1");
  private static final byte[] QUALIFIER = Bytes.toBytes("qual");
-
  private static HRegionServer badRS;
+ private static final Logger LOG = LoggerFactory.getLogger(TestMetaCache.class);
 
  /**
  * @throws java.lang.Exception
@@ -369,4 +371,77 @@ public void throwOnScan(FakeRSRpcServices rpcServices, ClientProtos.ScanRequest
  throws ServiceException {
  }
  }
+
+ @Test
+ public void testUserRegionLockThrowsException() throws IOException, InterruptedException {
+ ((FakeRSRpcServices)badRS.getRSRpcServices()).setExceptionInjector(new LockSleepInjector());
+ Configuration conf = new Configuration(TEST_UTIL.getConfiguration());
+ conf.setInt(HConstants.HBASE_CLIENT_RETRIES_NUMBER, 0);
+ conf.setLong(HConstants.HBASE_CLIENT_META_OPERATION_TIMEOUT, 2000);
+ conf.setLong(HConstants.HBASE_CLIENT_SCANNER_TIMEOUT_PERIOD, 2000);
+
+ try (ConnectionImplementation conn =
+ (ConnectionImplementation) ConnectionFactory.createConnection(conf)) {
+ ClientThread client1 = new ClientThread(conn);
+ ClientThread client2 = new ClientThread(conn);
+ client1.start();
+ client2.start();
+ client1.join();
+ client2.join();
+ // One thread will get the lock but will sleep in LockExceptionInjector#throwOnScan and
+ // eventually fail since the sleep time is more than hbase client scanner timeout period.
+ // Other thread will wait to acquire userRegionLock.
+ // Have no idea which thread will be scheduled first. So need to check both threads.
+
+ // Both the threads will throw exception. One thread will throw exception since after
+ // acquiring user region lock, it is sleeping for 5 seconds when the scanner time out period
+ // is 2 seconds.
+ // Other thread will throw exception since it was not able to get hold of user region lock
+ // within meta operation timeout period.
+ assertNotNull(client1.getException());
+ assertNotNull(client2.getException());
+
+ assertTrue(client1.getException() instanceof LockTimeoutException
+ ^ client2.getException() instanceof LockTimeoutException);
+ }
+ }
+
+ private final class ClientThread extends Thread {
+ private Exception exception;
+ private ConnectionImplementation connection;
+
+ private ClientThread(ConnectionImplementation connection) {
+ this.connection = connection;
+ }
+ @Override
+ public void run() {
+ byte[] currentKey = HConstants.EMPTY_START_ROW;
+ try {
+ connection.getRegionLocation(TABLE_NAME, currentKey, true);
+ } catch (IOException e) {
+ LOG.error("Thread id: " + this.getId() + " exception: ", e);
+ this.exception = e;
+ }
+ }
+ public Exception getException() {
+ return exception;
+ }
+ }
+
+ public static class LockSleepInjector extends ExceptionInjector {
+ @Override
+ public void throwOnScan(FakeRSRpcServices rpcServices, ClientProtos.ScanRequest request) {
+ try {
+ Thread.sleep(5000);
+ } catch (InterruptedException e) {
+ LOG.info("Interrupted exception", e);
+ }
+ }
+
+ @Override
+ public void throwOnGet(FakeRSRpcServices rpcServices, ClientProtos.GetRequest request) { }
+
+ @Override
+ public void throwOnMutate(FakeRSRpcServices rpcServices, ClientProtos.MutateRequest request) { }
+ }
 }