/**
* Reproduce locking up that happens when there's no further syncs after append fails, and causing
* an isolated sync then infinite wait. See HBASE-16960. If below is broken, we will see this test
* timeout because it is locked up.
*
* <p>Steps for reproduce:<br>
* 1. Trigger server abort through dodgyWAL1<br>
* 2. Add a {@link DummyWALActionsListener} to dodgyWAL2 to cause ringbuffer event handler thread
* sleep for a while thus keeping {@code endOfBatch} false<br>
* 3. Publish a sync then an append which will throw exception, check whether the sync could
* return
*/
@Test(timeout = 20000)
public void testLockup16960() throws IOException {
// A WAL that we can have throw exceptions when a flag is set.
class DodgyFSLog extends FSHLog {
// Set this when want the WAL to start throwing exceptions.
volatile boolean throwException = false;
public DodgyFSLog(FileSystem fs, Path root, String logDir, Configuration conf)
throws IOException {
super(fs, root, logDir, conf);
}
@Override
protected Writer createWriterInstance(Path path) throws IOException {
final Writer w = super.createWriterInstance(path);
return new Writer() {
@Override
public void close() throws IOException {
w.close();
}
@Override
public void sync() throws IOException {
if (throwException) {
throw new IOException("FAKE! Failed to replace a bad datanode...SYNC");
}
w.sync();
}
@Override
public void append(Entry entry) throws IOException {
if (throwException) {
throw new IOException("FAKE! Failed to replace a bad datanode...APPEND");
}
w.append(entry);
}
@Override
public long getLength() {
return w.getLength();
}
};
}
@Override
protected long doReplaceWriter(Path oldPath, Path newPath, Writer nextWriter)
throws IOException {
if (throwException) {
throw new FailedLogCloseException("oldPath=" + oldPath + ", newPath=" + newPath);
}
long oldFileLen = 0L;
oldFileLen = super.doReplaceWriter(oldPath, newPath, nextWriter);
return oldFileLen;
}
}
// Mocked up server and regionserver services. Needed below.
Server server =
new DummyServer(CONF, ServerName.valueOf("hostname1.example.org", 1234, 1L).toString());
RegionServerServices services = Mockito.mock(RegionServerServices.class);
CONF.setLong("hbase.regionserver.hlog.sync.timeout", 10000);
// OK. Now I have my mocked up Server & RegionServerServices and dodgy WAL,
// go ahead with test.
FileSystem fs = FileSystem.get(CONF);
Path rootDir = new Path(dir + getName());
DodgyFSLog dodgyWAL1 = new DodgyFSLog(fs, rootDir, getName(), CONF);
Path rootDir2 = new Path(dir + getName() + "2");
final DodgyFSLog dodgyWAL2 = new DodgyFSLog(fs, rootDir2, getName() + "2", CONF);
// Add a listener to force ringbuffer event handler sleep for a while
dodgyWAL2.registerWALActionsListener(new DummyWALActionsListener());
// I need a log roller running.
LogRoller logRoller = new LogRoller(server, services);
logRoller.addWAL(dodgyWAL1);
logRoller.addWAL(dodgyWAL2);
// There is no 'stop' once a logRoller is running.. it just dies.
logRoller.start();
// Now get a region and start adding in edits.
HTableDescriptor htd = new HTableDescriptor(TableName.META_TABLE_NAME);
final HRegion region = initHRegion(tableName, null, null, dodgyWAL1);
byte[] bytes = Bytes.toBytes(getName());
NavigableMap<byte[], Integer> scopes = new TreeMap<byte[], Integer>(Bytes.BYTES_COMPARATOR);
scopes.put(COLUMN_FAMILY_BYTES, 0);
MultiVersionConcurrencyControl mvcc = new MultiVersionConcurrencyControl();
try {
Put put = new Put(bytes);
put.addColumn(COLUMN_FAMILY_BYTES, Bytes.toBytes("1"), bytes);
WALKey key =
new WALKey(
region.getRegionInfo().getEncodedNameAsBytes(),
htd.getTableName(),
System.currentTimeMillis(),
mvcc,
scopes);
WALEdit edit = new WALEdit();
CellScanner CellScanner = put.cellScanner();
assertTrue(CellScanner.advance());
edit.add(CellScanner.current());
LOG.info("SET throwing of exception on append");
dodgyWAL1.throwException = true;
// This append provokes a WAL roll request
dodgyWAL1.append(region.getRegionInfo(), key, edit, true);
boolean exception = false;
try {
dodgyWAL1.sync();
} catch (Exception e) {
exception = true;
}
assertTrue("Did not get sync exception", exception);
// LogRoller call dodgyWAL1.rollWriter get FailedLogCloseException and
// cause server abort.
try {
// wait LogRoller exit.
Thread.sleep(50);
} catch (InterruptedException e) {
e.printStackTrace();
}
final CountDownLatch latch = new CountDownLatch(1);
// make RingBufferEventHandler sleep 1s, so the following sync
// endOfBatch=false
key =
new WALKey(
region.getRegionInfo().getEncodedNameAsBytes(),
TableName.valueOf("sleep"),
System.currentTimeMillis(),
mvcc,
scopes);
dodgyWAL2.append(region.getRegionInfo(), key, edit, true);
Thread t =
new Thread("Sync") {
public void run() {
try {
dodgyWAL2.sync();
} catch (IOException e) {
LOG.info("In sync", e);
}
latch.countDown();
LOG.info("Sync exiting");
};
};
t.setDaemon(true);
t.start();
try {
// make sure sync have published.
Thread.sleep(100);
} catch (InterruptedException e1) {
e1.printStackTrace();
}
// make append throw DamagedWALException
key =
new WALKey(
region.getRegionInfo().getEncodedNameAsBytes(),
TableName.valueOf("DamagedWALException"),
System.currentTimeMillis(),
mvcc,
scopes);
dodgyWAL2.append(region.getRegionInfo(), key, edit, true);
while (latch.getCount() > 0) {
Threads.sleep(100);
}
assertTrue(server.isAborted());
} finally {
if (logRoller != null) {
logRoller.close();
}
try {
if (region != null) {
region.close();
}
if (dodgyWAL1 != null) {
dodgyWAL1.close();
}
if (dodgyWAL2 != null) {
dodgyWAL2.close();
}
} catch (Exception e) {
LOG.info("On way out", e);
}
}
}
/**
* Reproduce locking up that happens when we get an inopportune sync during setup for zigzaglatch
* wait. See HBASE-14317. If below is broken, we will see this test timeout because it is locked
* up.
*
* <p>First I need to set up some mocks for Server and RegionServerServices. I also need to set up
* a dodgy WAL that will throw an exception when we go to append to it.
*/
@Test(timeout = 20000)
public void testLockupWhenSyncInMiddleOfZigZagSetup() throws IOException {
// A WAL that we can have throw exceptions when a flag is set.
class DodgyFSLog extends FSHLog {
// Set this when want the WAL to start throwing exceptions.
volatile boolean throwException = false;
// Latch to hold up processing until after another operation has had time to run.
CountDownLatch latch = new CountDownLatch(1);
public DodgyFSLog(FileSystem fs, Path root, String logDir, Configuration conf)
throws IOException {
super(fs, root, logDir, conf);
}
@Override
protected void afterCreatingZigZagLatch() {
// If throwException set, then append will throw an exception causing the WAL to be
// rolled. We'll come in here. Hold up processing until a sync can get in before
// the zigzag has time to complete its setup and get its own sync in. This is what causes
// the lock up we've seen in production.
if (throwException) {
try {
LOG.info("LATCHED");
// So, timing can have it that the test can run and the bad flush below happens
// before we get here. In this case, we'll be stuck waiting on this latch but there
// is nothing in the WAL pipeline to get us to the below beforeWaitOnSafePoint...
// because all WALs have rolled. In this case, just give up on test.
if (!this.latch.await(5, TimeUnit.SECONDS)) {
LOG.warn("GIVE UP! Failed waiting on latch...Test is ABORTED!");
}
} catch (InterruptedException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
}
@Override
protected void beforeWaitOnSafePoint() {
if (throwException) {
LOG.info("COUNTDOWN");
// Don't countdown latch until someone waiting on it otherwise, the above
// afterCreatingZigZagLatch will get to the latch and no one will ever free it and we'll
// be stuck; test won't go down
while (this.latch.getCount() <= 0) Threads.sleep(1);
this.latch.countDown();
}
}
@Override
protected Writer createWriterInstance(Path path) throws IOException {
final Writer w = super.createWriterInstance(path);
return new Writer() {
@Override
public void close() throws IOException {
w.close();
}
@Override
public void sync() throws IOException {
if (throwException) {
throw new IOException("FAKE! Failed to replace a bad datanode...SYNC");
}
w.sync();
}
@Override
public void append(Entry entry) throws IOException {
if (throwException) {
throw new IOException("FAKE! Failed to replace a bad datanode...APPEND");
}
w.append(entry);
}
@Override
public long getLength() {
return w.getLength();
}
};
}
}
// Mocked up server and regionserver services. Needed below.
Server server = Mockito.mock(Server.class);
Mockito.when(server.getConfiguration()).thenReturn(CONF);
Mockito.when(server.isStopped()).thenReturn(false);
Mockito.when(server.isAborted()).thenReturn(false);
RegionServerServices services = Mockito.mock(RegionServerServices.class);
// OK. Now I have my mocked up Server & RegionServerServices and dodgy WAL, go ahead with test.
FileSystem fs = FileSystem.get(CONF);
Path rootDir = new Path(dir + getName());
DodgyFSLog dodgyWAL = new DodgyFSLog(fs, rootDir, getName(), CONF);
Path originalWAL = dodgyWAL.getCurrentFileName();
// I need a log roller running.
LogRoller logRoller = new LogRoller(server, services);
logRoller.addWAL(dodgyWAL);
// There is no 'stop' once a logRoller is running.. it just dies.
logRoller.start();
// Now get a region and start adding in edits.
HTableDescriptor htd = new HTableDescriptor(TableName.META_TABLE_NAME);
final HRegion region = initHRegion(tableName, null, null, dodgyWAL);
byte[] bytes = Bytes.toBytes(getName());
NavigableMap<byte[], Integer> scopes = new TreeMap<byte[], Integer>(Bytes.BYTES_COMPARATOR);
scopes.put(COLUMN_FAMILY_BYTES, 0);
MultiVersionConcurrencyControl mvcc = new MultiVersionConcurrencyControl();
try {
// First get something into memstore. Make a Put and then pull the Cell out of it. Will
// manage append and sync carefully in below to manufacture hang. We keep adding same
// edit. WAL subsystem doesn't care.
Put put = new Put(bytes);
put.addColumn(COLUMN_FAMILY_BYTES, Bytes.toBytes("1"), bytes);
WALKey key =
new WALKey(
region.getRegionInfo().getEncodedNameAsBytes(),
htd.getTableName(),
System.currentTimeMillis(),
mvcc,
scopes);
WALEdit edit = new WALEdit();
CellScanner CellScanner = put.cellScanner();
assertTrue(CellScanner.advance());
edit.add(CellScanner.current());
// Put something in memstore and out in the WAL. Do a big number of appends so we push
// out other side of the ringbuffer. If small numbers, stuff doesn't make it to WAL
for (int i = 0; i < 1000; i++) {
region.put(put);
}
// Set it so we start throwing exceptions.
LOG.info("SET throwing of exception on append");
dodgyWAL.throwException = true;
// This append provokes a WAL roll request
dodgyWAL.append(region.getRegionInfo(), key, edit, true);
boolean exception = false;
try {
dodgyWAL.sync();
} catch (Exception e) {
exception = true;
}
assertTrue("Did not get sync exception", exception);
// Get a memstore flush going too so we have same hung profile as up in the issue over
// in HBASE-14317. Flush hangs trying to get sequenceid because the ringbuffer is held up
// by the zigzaglatch waiting on syncs to come home.
Thread t =
new Thread("Flusher") {
public void run() {
try {
if (region.getMemstoreSize() <= 0) {
throw new IOException("memstore size=" + region.getMemstoreSize());
}
region.flush(false);
} catch (IOException e) {
// Can fail trying to flush in middle of a roll. Not a failure. Will succeed later
// when roll completes.
LOG.info("In flush", e);
}
LOG.info("Exiting");
};
};
t.setDaemon(true);
t.start();
// Wait until
while (dodgyWAL.latch.getCount() > 0) Threads.sleep(1);
// Now assert I got a new WAL file put in place even though loads of errors above.
assertTrue(originalWAL != dodgyWAL.getCurrentFileName());
// Can I append to it?
dodgyWAL.throwException = false;
try {
region.put(put);
} catch (Exception e) {
LOG.info("In the put", e);
}
} finally {
// To stop logRoller, its server has to say it is stopped.
Mockito.when(server.isStopped()).thenReturn(true);
if (logRoller != null) logRoller.close();
try {
if (region != null) region.close();
if (dodgyWAL != null) dodgyWAL.close();
} catch (Exception e) {
LOG.info("On way out", e);
}
}
}
