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HBASE-19772 Do not close connection to zk when there are still pending request in ReadOnlyZKClient

This commit is contained in:
zhangduo 2018-01-12 09:43:56 +08:00
parent f91589d305
commit 842f794a62
2 changed files with 92 additions and 58 deletions
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79
hbase-client/src/main/java/org/apache/hadoop/hbase/zookeeper/ReadOnlyZKClient.java
View File

@ -29,9 +29,8 @@ import java.util.concurrent.DelayQueue;
import java.util.concurrent.Delayed;
import java.util.concurrent.TimeUnit;
import java.util.concurrent.atomic.AtomicBoolean;
import org.apache.hadoop.conf.Configuration;
import org.apache.hadoop.hbase.ZooKeeperConnectionException;
import org.apache.hadoop.hbase.util.Threads;
import org.apache.yetus.audience.InterfaceAudience;
import org.apache.zookeeper.KeeperException;
import org.apache.zookeeper.KeeperException.Code;
@ -39,6 +38,7 @@ import org.apache.zookeeper.ZooKeeper;
import org.apache.zookeeper.data.Stat;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.apache.hbase.thirdparty.com.google.common.annotations.VisibleForTesting;
/**
@ -114,7 +114,10 @@ public final class ReadOnlyZKClient implements Closeable {
private final AtomicBoolean closed = new AtomicBoolean(false);
private ZooKeeper zookeeper;
@VisibleForTesting
ZooKeeper zookeeper;
private int pendingRequests = 0;
private String getId() {
return String.format("0x%08x", System.identityHashCode(this));
@ -127,12 +130,12 @@ public final class ReadOnlyZKClient implements Closeable {
this.retryIntervalMs =
conf.getInt(RECOVERY_RETRY_INTERVAL_MILLIS, DEFAULT_RECOVERY_RETRY_INTERVAL_MILLIS);
this.keepAliveTimeMs = conf.getInt(KEEPALIVE_MILLIS, DEFAULT_KEEPALIVE_MILLIS);
LOG.info("Start read only zookeeper connection " + getId() + " to " + connectString +
", session timeout " + sessionTimeoutMs + " ms, retries " + maxRetries +
", retry interval " + retryIntervalMs + " ms, keep alive " + keepAliveTimeMs + " ms");
Thread t = new Thread(this::run, "ReadOnlyZKClient");
t.setDaemon(true);
t.start();
LOG.info(
"Start read only zookeeper connection {} to {}, " + "session timeout {} ms, retries {}, " +
"retry interval {} ms, keep alive {} ms",
getId(), connectString, sessionTimeoutMs, maxRetries, retryIntervalMs, keepAliveTimeMs);
Threads.setDaemonThreadRunning(new Thread(this::run),
"ReadOnlyZKClient-" + connectString + "@" + getId());
}
private abstract class ZKTask<T> extends Task {
@ -156,6 +159,7 @@ public final class ReadOnlyZKClient implements Closeable {
@Override
public void exec(ZooKeeper alwaysNull) {
pendingRequests--;
Code code = Code.get(rc);
if (code == Code.OK) {
future.complete(ret);
@ -169,19 +173,19 @@ public final class ReadOnlyZKClient implements Closeable {
future.completeExceptionally(KeeperException.create(code, path));
} else {
if (code == Code.SESSIONEXPIRED) {
LOG.warn(getId() + " session expired, close and reconnect");
LOG.warn("{} to {} session expired, close and reconnect", getId(), connectString);
try {
zk.close();
} catch (InterruptedException e) {
}
}
if (ZKTask.this.delay(retryIntervalMs, maxRetries)) {
LOG.warn(getId() + " failed for " + operationType + " of " + path + ", code = " +
code + ", retries = " + ZKTask.this.retries);
LOG.warn("{} to {} failed for {} of {}, code = {}, retries = {}", getId(),
connectString, operationType, path, code, ZKTask.this.retries);
tasks.add(ZKTask.this);
} else {
LOG.warn(getId() + " failed for " + operationType + " of " + path + ", code = " +
code + ", retries = " + ZKTask.this.retries + ", give up");
LOG.warn("{} to {} failed for {} of {}, code = {}, retries = {}, give up", getId(),
connectString, operationType, path, code, ZKTask.this.retries);
future.completeExceptionally(KeeperException.create(code, path));
}
}
@ -205,6 +209,14 @@ public final class ReadOnlyZKClient implements Closeable {
return true;
}
protected abstract void doExec(ZooKeeper zk);
@Override
public final void exec(ZooKeeper zk) {
pendingRequests++;
doExec(zk);
}
public boolean delay(long intervalMs, int maxRetries) {
if (retries >= maxRetries) {
return false;
@ -217,14 +229,12 @@ public final class ReadOnlyZKClient implements Closeable {
@Override
public void connectFailed(IOException e) {
if (delay(retryIntervalMs, maxRetries)) {
LOG.warn(getId() + " failed to connect to zk for " + operationType + " of " + path +
", retries = " + retries,
e);
LOG.warn("{} to {} failed to connect to zk fo {} of {}, retries = {}", getId(),
connectString, operationType, path, retries, e);
tasks.add(this);
} else {
LOG.warn(getId() + " failed to connect to zk for " + operationType + " of " + path +
", retries = " + retries + ", give up",
e);
LOG.warn("{} to {} failed to connect to zk fo {} of {}, retries = {}, give up", getId(),
connectString, operationType, path, retries, e);
future.completeExceptionally(e);
}
}
@ -249,7 +259,7 @@ public final class ReadOnlyZKClient implements Closeable {
tasks.add(new ZKTask<byte[]>(path, future, "get") {
@Override
public void exec(ZooKeeper zk) {
protected void doExec(ZooKeeper zk) {
zk.getData(path, false,
(rc, path, ctx, data, stat) -> onComplete(zk, rc, data, true), null);
}
@ -265,7 +275,7 @@ public final class ReadOnlyZKClient implements Closeable {
tasks.add(new ZKTask<Stat>(path, future, "exists") {
@Override
public void exec(ZooKeeper zk) {
protected void doExec(ZooKeeper zk) {
zk.exists(path, false, (rc, path, ctx, stat) -> onComplete(zk, rc, stat, false), null);
}
});
@ -286,16 +296,6 @@ public final class ReadOnlyZKClient implements Closeable {
// may be closed when session expired
if (zookeeper == null || !zookeeper.getState().isAlive()) {
zookeeper = new ZooKeeper(connectString, sessionTimeoutMs, e -> {});
int timeout = 10000;
try {
// Before returning, try and ensure we are connected. Don't wait long in case
// we are trying to connect to a cluster that is down. If we fail to connect,
// just catch the exception and carry-on. The first usage will fail and we'll
// cleanup.
zookeeper = ZooKeeperHelper.ensureConnectedZooKeeper(zookeeper, timeout);
} catch (ZooKeeperConnectionException e) {
LOG.warn("Failed connecting after waiting " + timeout + "ms; " + zookeeper);
}
}
return zookeeper;
}
@ -311,9 +311,11 @@ public final class ReadOnlyZKClient implements Closeable {
if (task == CLOSE) {
break;
}
if (task == null) {
LOG.info(getId() + " no activities for " + keepAliveTimeMs +
" ms, close active connection. Will reconnect next time when there are new requests.");
if (task == null && pendingRequests == 0) {
LOG.debug(
"{} to {} no activities for {} ms, close active connection. " +
"Will reconnect next time when there are new requests",
getId(), connectString, keepAliveTimeMs);
closeZk();
continue;
}
@ -339,16 +341,11 @@ public final class ReadOnlyZKClient implements Closeable {
@Override
public void close() {
if (closed.compareAndSet(false, true)) {
LOG.info("Close zookeeper connection " + getId() + " to " + connectString);
LOG.info("Close zookeeper connection {} to {}", getId(), connectString);
tasks.add(CLOSE);
}
}
@VisibleForTesting
ZooKeeper getZooKeeper() {
return zookeeper;
}
@VisibleForTesting
public String getConnectString() {
return connectString;

71
hbase-zookeeper/src/test/java/org/apache/hadoop/hbase/zookeeper/TestReadOnlyZKClient.java
View File

@ -1,4 +1,4 @@
/*
/**
* 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
@ -27,26 +27,36 @@ import static org.junit.Assert.assertNull;
import static org.junit.Assert.assertSame;
import static org.junit.Assert.assertThat;
import static org.junit.Assert.fail;
import static org.mockito.ArgumentMatchers.any;
import static org.mockito.ArgumentMatchers.anyBoolean;
import static org.mockito.ArgumentMatchers.anyString;
import static org.mockito.Mockito.doAnswer;
import static org.mockito.Mockito.spy;
import java.io.IOException;
import java.util.concurrent.CompletableFuture;
import java.util.concurrent.CountDownLatch;
import java.util.concurrent.ExecutionException;
import java.util.concurrent.ThreadLocalRandom;
import org.apache.hadoop.conf.Configuration;
import org.apache.hadoop.hbase.HBaseZKTestingUtility;
import org.apache.hadoop.hbase.HConstants;
import org.apache.hadoop.hbase.Waiter.ExplainingPredicate;
import org.apache.hadoop.hbase.testclassification.MediumTests;
import org.apache.hadoop.hbase.testclassification.ZKTests;
import org.apache.zookeeper.AsyncCallback.StatCallback;
import org.apache.zookeeper.CreateMode;
import org.apache.zookeeper.KeeperException;
import org.apache.zookeeper.KeeperException.Code;
import org.apache.zookeeper.ZooDefs;
import org.apache.zookeeper.ZooKeeper;
import org.apache.zookeeper.data.Stat;
import org.junit.AfterClass;
import org.junit.BeforeClass;
import org.junit.Test;
import org.junit.experimental.categories.Category;
import org.mockito.invocation.InvocationOnMock;
import org.mockito.stubbing.Answer;
@Category({ ZKTests.class, MediumTests.class })
public class TestReadOnlyZKClient {
@ -67,8 +77,7 @@ public class TestReadOnlyZKClient {
public static void setUp() throws Exception {
PORT = UTIL.startMiniZKCluster().getClientPort();
ZooKeeper zk = ZooKeeperHelper.
getConnectedZooKeeper("localhost:" + PORT, 10000);
ZooKeeper zk = ZooKeeperHelper.getConnectedZooKeeper("localhost:" + PORT, 10000);
DATA = new byte[10];
ThreadLocalRandom.current().nextBytes(DATA);
zk.create(PATH, DATA, ZooDefs.Ids.OPEN_ACL_UNSAFE, CreateMode.PERSISTENT);
@ -83,7 +92,7 @@ public class TestReadOnlyZKClient {
conf.setInt(ReadOnlyZKClient.KEEPALIVE_MILLIS, 3000);
RO_ZK = new ReadOnlyZKClient(conf);
// only connect when necessary
assertNull(RO_ZK.getZooKeeper());
assertNull(RO_ZK.zookeeper);
}
@AfterClass
@ -93,17 +102,13 @@ public class TestReadOnlyZKClient {
UTIL.cleanupTestDir();
}
@Test
public void testGetAndExists() throws Exception {
assertArrayEquals(DATA, RO_ZK.get(PATH).get());
assertEquals(CHILDREN, RO_ZK.exists(PATH).get().getNumChildren());
assertNotNull(RO_ZK.getZooKeeper());
private void waitForIdleConnectionClosed() throws Exception {
// The zookeeper client should be closed finally after the keep alive time elapsed
UTIL.waitFor(10000, new ExplainingPredicate<Exception>() {
@Override
public boolean evaluate() throws Exception {
return RO_ZK.getZooKeeper() == null;
return RO_ZK.zookeeper == null;
}
@Override
@ -113,6 +118,14 @@ public class TestReadOnlyZKClient {
});
}
@Test
public void testGetAndExists() throws Exception {
assertArrayEquals(DATA, RO_ZK.get(PATH).get());
assertEquals(CHILDREN, RO_ZK.exists(PATH).get().getNumChildren());
assertNotNull(RO_ZK.zookeeper);
waitForIdleConnectionClosed();
}
@Test
public void testNoNode() throws InterruptedException, ExecutionException {
String pathNotExists = PATH + "_whatever";
@ -132,15 +145,39 @@ public class TestReadOnlyZKClient {
@Test
public void testSessionExpire() throws Exception {
assertArrayEquals(DATA, RO_ZK.get(PATH).get());
ZooKeeper zk = RO_ZK.getZooKeeper();
ZooKeeper zk = RO_ZK.zookeeper;
long sessionId = zk.getSessionId();
UTIL.getZkCluster().getZooKeeperServers().get(0).closeSession(sessionId);
// should not reach keep alive so still the same instance
assertSame(zk, RO_ZK.getZooKeeper());
byte [] got = RO_ZK.get(PATH).get();
assertSame(zk, RO_ZK.zookeeper);
byte[] got = RO_ZK.get(PATH).get();
assertArrayEquals(DATA, got);
assertNotNull(RO_ZK.getZooKeeper());
assertNotSame(zk, RO_ZK.getZooKeeper());
assertNotEquals(sessionId, RO_ZK.getZooKeeper().getSessionId());
assertNotNull(RO_ZK.zookeeper);
assertNotSame(zk, RO_ZK.zookeeper);
assertNotEquals(sessionId, RO_ZK.zookeeper.getSessionId());
}
@Test
public void testNotCloseZkWhenPending() throws Exception {
assertArrayEquals(DATA, RO_ZK.get(PATH).get());
ZooKeeper mockedZK = spy(RO_ZK.zookeeper);
CountDownLatch latch = new CountDownLatch(1);
doAnswer(new Answer<Object>() {
@Override
public Object answer(InvocationOnMock invocation) throws Throwable {
latch.await();
return invocation.callRealMethod();
}
}).when(mockedZK).exists(anyString(), anyBoolean(), any(StatCallback.class), any());
RO_ZK.zookeeper = mockedZK;
CompletableFuture<Stat> future = RO_ZK.exists(PATH);
// 2 * keep alive time to ensure that we will not close the zk when there are pending requests
Thread.sleep(6000);
assertNotNull(RO_ZK.zookeeper);
latch.countDown();
assertEquals(CHILDREN, future.get().getNumChildren());
// now we will close the idle connection.
waitForIdleConnectionClosed();
}
}