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h2database
提交 6a346cba authored 作者: Noel Grandin's avatar Noel Grandin
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add deadlock detector that runs every 10 seconds and prints out info 

about which tables each thread has locked
上级 0b9fb0ed
隐藏空白字符变更
内嵌 并排
正在显示 包含 222 行增加 和 0 行删除
h2/src/main/org/h2/engine/Engine.java
浏览文件 @ 6a346cba
......@@ -17,6 +17,7 @@ import org.h2.store.FileLock;
import org.h2.util.MathUtils;
import org.h2.util.New;
import org.h2.util.StringUtils;
import org.h2.util.ThreadDeadlockDetector;
import org.h2.util.Utils;
/**
......@@ -35,6 +36,7 @@ public class Engine implements SessionFactory {
private Engine() {
// use getInstance()
ThreadDeadlockDetector.init();
}
public static Engine getInstance() {
......
h2/src/main/org/h2/mvstore/db/MVTable.java
浏览文件 @ 6a346cba
......@@ -11,6 +11,7 @@ import java.util.Collections;
import java.util.Comparator;
import java.util.Set;
import java.util.concurrent.ConcurrentHashMap;
import org.h2.api.DatabaseEventListener;
import org.h2.api.ErrorCode;
import org.h2.command.ddl.Analyze;
......@@ -37,6 +38,7 @@ import org.h2.table.Column;
import org.h2.table.IndexColumn;
import org.h2.table.Table;
import org.h2.table.TableBase;
import org.h2.util.DebuggingThreadLocal;
import org.h2.util.MathUtils;
import org.h2.util.New;
import org.h2.value.DataType;
......@@ -56,6 +58,10 @@ public class MVTable extends TableBase {
private final ConcurrentHashMap<Session, Session> lockSharedSessions =
new ConcurrentHashMap<Session, Session>();
public static final DebuggingThreadLocal<String> WAITING_FOR_LOCK = new DebuggingThreadLocal<String>();
public static final DebuggingThreadLocal<ArrayList<String>> EXCLUSIVE_LOCKS = new DebuggingThreadLocal<ArrayList<String>>();
public static final DebuggingThreadLocal<ArrayList<String>> SHARED_LOCKS = new DebuggingThreadLocal<ArrayList<String>>();
/**
* The queue of sessions waiting to lock the table. It is a FIFO queue to
* prevent starvation, since Java's synchronized locking is biased.
......@@ -130,11 +136,13 @@ public class MVTable extends TableBase {
return true;
}
session.setWaitForLock(this, Thread.currentThread());
WAITING_FOR_LOCK.set(getName());
waitingSessions.addLast(session);
try {
doLock1(session, lockMode, exclusive);
} finally {
session.setWaitForLock(null, null);
WAITING_FOR_LOCK.remove();
waitingSessions.remove(session);
}
}
......@@ -218,11 +226,19 @@ public class MVTable extends TableBase {
traceLock(session, exclusive, "added for");
session.addLock(this);
lockExclusiveSession = session;
if (EXCLUSIVE_LOCKS.get() == null) {
EXCLUSIVE_LOCKS.set(new ArrayList<String>());
}
EXCLUSIVE_LOCKS.get().add(getName());
return true;
} else if (lockSharedSessions.size() == 1 &&
lockSharedSessions.containsKey(session)) {
traceLock(session, exclusive, "add (upgraded) for ");
lockExclusiveSession = session;
if (EXCLUSIVE_LOCKS.get() == null) {
EXCLUSIVE_LOCKS.set(new ArrayList<String>());
}
EXCLUSIVE_LOCKS.get().add(getName());
return true;
}
}
......@@ -244,6 +260,10 @@ public class MVTable extends TableBase {
traceLock(session, exclusive, "ok");
session.addLock(this);
lockSharedSessions.put(session, session);
if (SHARED_LOCKS.get() == null) {
SHARED_LOCKS.set(new ArrayList<String>());
}
SHARED_LOCKS.get().add(getName());
}
return true;
}
......@@ -357,10 +377,16 @@ public class MVTable extends TableBase {
traceLock(s, lockExclusiveSession == s, "unlock");
if (lockExclusiveSession == s) {
lockExclusiveSession = null;
if (EXCLUSIVE_LOCKS.get() != null) {
EXCLUSIVE_LOCKS.get().remove(getName());
}
}
synchronized (getLockSyncObject()) {
if (lockSharedSessions.size() > 0) {
lockSharedSessions.remove(s);
if (SHARED_LOCKS.get() != null) {
SHARED_LOCKS.get().remove(getName());
}
}
if (!waitingSessions.isEmpty()) {
getLockSyncObject().notifyAll();
......
h2/src/main/org/h2/util/DebuggingThreadLocal.java 0 → 100644
浏览文件 @ 6a346cba
/*
* Copyright 2004-2014 H2 Group. Multiple-Licensed under the MPL 2.0,
* and the EPL 1.0 (http://h2database.com/html/license.html).
* Initial Developer: H2 Group
*/
package org.h2.util;
import java.util.HashMap;
import java.util.concurrent.ConcurrentHashMap;
/**
* Similar to ThreadLocal, except that it allows it's data to be read from other threads - useful for debugging info.
*/
public class DebuggingThreadLocal<T>
{
private final ConcurrentHashMap<Long, T> map = new ConcurrentHashMap<Long, T>();
public DebuggingThreadLocal() {
}
public void set(T value) {
map.put(Thread.currentThread().getId(), value);
}
public void remove() {
map.remove(Thread.currentThread().getId());
}
public T get() {
return map.get(Thread.currentThread().getId());
}
/**
* @return a HashMap containing a mapping from thread-id to value
*/
public HashMap<Long,T> getSnapshotOfAllThreads() {
return new HashMap<Long,T>(map);
}
public T deepCopy(T value) {
return value;
}
}
h2/src/main/org/h2/util/ThreadDeadlockDetector.java 0 → 100644
浏览文件 @ 6a346cba
/*
* Copyright 2004-2014 H2 Group. Multiple-Licensed under the MPL 2.0,
* and the EPL 1.0 (http://h2database.com/html/license.html).
* Initial Developer: H2 Group
*/
package org.h2.util;
import java.io.PrintWriter;
import java.io.StringWriter;
import java.lang.management.LockInfo;
import java.lang.management.ManagementFactory;
import java.lang.management.MonitorInfo;
import java.lang.management.ThreadInfo;
import java.lang.management.ThreadMXBean;
import java.util.ArrayList;
import java.util.HashMap;
import java.util.Timer;
import java.util.TimerTask;
import org.h2.mvstore.db.MVTable;
/**
* Detects deadlocks between threads. Prints out data in the same format as the CTRL-BREAK handler,
* but includes information about table locks.
*/
public class ThreadDeadlockDetector
{
private static String INDENT = " ";
private final ThreadMXBean tmbean;
private final Timer threadCheck = new Timer("ThreadDeadlockDetector", true/* isDaemon */);
private static ThreadDeadlockDetector detector = null;
public synchronized static void init() {
if (detector == null) {
detector = new ThreadDeadlockDetector();
}
}
private ThreadDeadlockDetector() {
this.tmbean = ManagementFactory.getThreadMXBean();
threadCheck.schedule(new TimerTask() {
@Override
public void run() {
checkForDeadlocks();
}
}, 10/*delay(ms)*/, 10000/*period(ms)*/);
}
/**
* Checks if any threads are deadlocked. If any, print the thread dump information.
*/
private void checkForDeadlocks() {
long[] tids = tmbean.findDeadlockedThreads();
if (tids == null) {
return;
}
final StringWriter stringWriter = new StringWriter();
final PrintWriter print = new PrintWriter(stringWriter);
print.println("ThreadDeadlockDetector - deadlock found :");
final ThreadInfo[] infos = tmbean.getThreadInfo(tids, true, true);
final HashMap<Long,String> mvtableWaitingForLockMap =
MVTable.WAITING_FOR_LOCK.getSnapshotOfAllThreads();
final HashMap<Long,ArrayList<String>> mvtableExclusiveLocksMap =
MVTable.EXCLUSIVE_LOCKS.getSnapshotOfAllThreads();
final HashMap<Long,ArrayList<String>> mvtableSharedLocksMap =
MVTable.SHARED_LOCKS.getSnapshotOfAllThreads();
for (ThreadInfo ti : infos) {
printThreadInfo(print, ti);
printLockInfo(print, ti.getLockedSynchronizers(),
mvtableWaitingForLockMap.get(ti.getThreadId()),
mvtableExclusiveLocksMap.get(ti.getThreadId()),
mvtableSharedLocksMap.get(ti.getThreadId()));
}
print.flush();
// Dump it to system.out in one block, so it doesn't get mixed up with other stuff when we're
// using a logging subsystem.
System.out.println(stringWriter.getBuffer());
}
private static void printThreadInfo(PrintWriter print, ThreadInfo ti) {
// print thread information
printThread(print, ti);
// print stack trace with locks
StackTraceElement[] stacktrace = ti.getStackTrace();
MonitorInfo[] monitors = ti.getLockedMonitors();
for (int i = 0; i < stacktrace.length; i++) {
StackTraceElement ste = stacktrace[i];
print.println(INDENT + "at " + ste.toString());
for (MonitorInfo mi : monitors) {
if (mi.getLockedStackDepth() == i) {
print.println(INDENT + " - locked " + mi);
}
}
}
print.println();
}
private static void printThread(PrintWriter print, ThreadInfo ti) {
print.print("\"" + ti.getThreadName() + "\"" + " Id="
+ ti.getThreadId() + " in " + ti.getThreadState());
if (ti.getLockName() != null) {
print.append(" on lock=" + ti.getLockName());
}
if (ti.isSuspended()) {
print.append(" (suspended)");
}
if (ti.isInNative()) {
print.append(" (running in native)");
}
print.println();
if (ti.getLockOwnerName() != null) {
print.println(INDENT + " owned by " + ti.getLockOwnerName() + " Id="
+ ti.getLockOwnerId());
}
}
private static void printLockInfo(PrintWriter print, LockInfo[] locks,
String mvtableWaitingForLock,
ArrayList<String> mvtableExclusiveLocks,
ArrayList<String> mvtableSharedLocksMap) {
print.println(INDENT + "Locked synchronizers: count = " + locks.length);
for (LockInfo li : locks) {
print.println(INDENT + " - " + li);
}
if (mvtableWaitingForLock != null) {
print.println(INDENT + "Waiting for table: " + mvtableWaitingForLock);
}
if (mvtableExclusiveLocks != null) {
print.println(INDENT + "Exclusive table locks: count = " + mvtableExclusiveLocks.size());
for (String name : mvtableExclusiveLocks) {
print.println(INDENT + " - " + name);
}
}
if (mvtableSharedLocksMap != null) {
print.println(INDENT + "Shared table locks: count = " + mvtableSharedLocksMap.size());
for (String name : mvtableSharedLocksMap) {
print.println(INDENT + " - " + name);
}
}
print.println();
}
}
\ No newline at end of file
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