HBASE-20458 Support removing a WAL from LogRoller

hbase-server/src/main/java/org/apache/hadoop/hbase/regionserver/LogRoller.java

@@ -20,6 +20,8 @@ package org.apache.hadoop.hbase.regionserver;
 
 import java.io.Closeable;
 import java.io.IOException;
+import java.util.Iterator;
+import java.util.Map;
 import java.util.Map.Entry;
 import java.util.concurrent.ConcurrentHashMap;
 import java.util.concurrent.atomic.AtomicBoolean;
@@ -30,6 +32,7 @@ import org.apache.hadoop.hbase.Server;
 import org.apache.hadoop.hbase.regionserver.wal.AbstractFSWAL;
 import org.apache.hadoop.hbase.regionserver.wal.FailedLogCloseException;
 import org.apache.hadoop.hbase.regionserver.wal.WALActionsListener;
+import org.apache.hadoop.hbase.regionserver.wal.WALClosedException;
 import org.apache.hadoop.hbase.util.Bytes;
 import org.apache.hadoop.hbase.util.HasThread;
 import org.apache.hadoop.hbase.wal.WAL;
@@ -177,18 +180,25 @@ public class LogRoller extends HasThread implements Closeable {
       rollLock.lock(); // FindBugs UL_UNRELEASED_LOCK_EXCEPTION_PATH
       try {
         this.lastrolltime = now;
-        for (Entry<WAL, Boolean> entry : walNeedsRoll.entrySet()) {
+        for (Iterator<Entry<WAL, Boolean>> iter = walNeedsRoll.entrySet().iterator(); iter
+            .hasNext();) {
+          Entry<WAL, Boolean> entry = iter.next();
           final WAL wal = entry.getKey();
           // Force the roll if the logroll.period is elapsed or if a roll was requested.
           // The returned value is an array of actual region names.
-          final byte [][] regionsToFlush = wal.rollWriter(periodic ||
-              entry.getValue().booleanValue());
+          try {
+            final byte[][] regionsToFlush =
+                wal.rollWriter(periodic || entry.getValue().booleanValue());
             walNeedsRoll.put(wal, Boolean.FALSE);
             if (regionsToFlush != null) {
               for (byte[] r : regionsToFlush) {
                 scheduleFlush(r);
               }
             }
+          } catch (WALClosedException e) {
+            LOG.warn("WAL has been closed. Skipping rolling of writer and just remove it", e);
+            iter.remove();
+          }
         }
       } catch (FailedLogCloseException e) {
         abort("Failed log close in log roller", e);
@@ -252,4 +262,9 @@ public class LogRoller extends HasThread implements Closeable {
     running = false;
     interrupt();
   }
+
+  @VisibleForTesting
+  Map<WAL, Boolean> getWalNeedsRoll() {
+    return this.walNeedsRoll;
+  }
 }

hbase-server/src/main/java/org/apache/hadoop/hbase/regionserver/wal/AbstractFSWAL.java

@@ -754,15 +754,14 @@ public abstract class AbstractFSWAL<W extends WriterBase> implements WAL {
   public byte[][] rollWriter(boolean force) throws FailedLogCloseException, IOException {
     rollWriterLock.lock();
     try {
+      if (this.closed) {
+        throw new WALClosedException("WAL has been closed");
+      }
       // Return if nothing to flush.
       if (!force && this.writer != null && this.numEntries.get() <= 0) {
         return null;
       }
       byte[][] regionsToFlush = null;
-      if (this.closed) {
-        LOG.debug("WAL closed. Skipping rolling of writer");
-        return regionsToFlush;
-      }
       try (TraceScope scope = TraceUtil.createTrace("FSHLog.rollWriter")) {
         Path oldPath = getOldPath();
         Path newPath = getNewPath();

hbase-server/src/main/java/org/apache/hadoop/hbase/regionserver/wal/WALClosedException.java

@@ -0,0 +1,47 @@
+/**
+ * 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.regionserver.wal;
+
+import java.io.IOException;
+
+import org.apache.hadoop.hbase.regionserver.LogRoller;
+import org.apache.hadoop.hbase.replication.SyncReplicationState;
+import org.apache.yetus.audience.InterfaceAudience;
+
+/**
+ * Thrown when {@link LogRoller} try to roll writer but the WAL already was closed. This may
+ * happened when peer's sync replication state was transited from
+ * {@link SyncReplicationState#ACTIVE} to {@link SyncReplicationState#DOWNGRADE_ACTIVE} and the
+ * region's WAL was changed to a new one. But the old WAL was still left in {@link LogRoller}.
+ */
+@InterfaceAudience.Private
+public class WALClosedException extends IOException {
+
+  private static final long serialVersionUID = -3183198896865290678L;
+
+  public WALClosedException() {
+    super();
+  }
+
+  /**
+   * @param msg exception message
+   */
+  public WALClosedException(String msg) {
+    super(msg);
+  }
+}

hbase-server/src/test/java/org/apache/hadoop/hbase/regionserver/TestLogRoller.java

@@ -0,0 +1,90 @@
+/**
+ * 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.regionserver;
+
+import static org.junit.Assert.assertEquals;
+import static org.junit.Assert.assertFalse;
+import static org.junit.Assert.assertTrue;
+
+import org.apache.hadoop.conf.Configuration;
+import org.apache.hadoop.hbase.HBaseClassTestRule;
+import org.apache.hadoop.hbase.HBaseTestingUtility;
+import org.apache.hadoop.hbase.regionserver.wal.FSHLog;
+import org.apache.hadoop.hbase.testclassification.MediumTests;
+import org.apache.hadoop.hbase.testclassification.RegionServerTests;
+import org.apache.hadoop.hbase.wal.AbstractFSWALProvider;
+import org.junit.After;
+import org.junit.Before;
+import org.junit.ClassRule;
+import org.junit.Test;
+import org.junit.experimental.categories.Category;
+
+@Category({RegionServerTests.class, MediumTests.class})
+public class TestLogRoller {
+
+  @ClassRule
+  public static final HBaseClassTestRule CLASS_RULE =
+      HBaseClassTestRule.forClass(TestLogRoller.class);
+
+  private static HBaseTestingUtility TEST_UTIL = new HBaseTestingUtility();
+
+  private static final int logRollPeriod = 20 * 1000;
+
+  @Before
+  public void setup() throws Exception {
+    TEST_UTIL.getConfiguration().setInt("hbase.regionserver.logroll.period", logRollPeriod);
+    TEST_UTIL.startMiniCluster(1);
+  }
+
+  @After
+  public void tearDown() throws Exception {
+    TEST_UTIL.shutdownMiniCluster();
+  }
+
+  @Test
+  public void testRemoveClosedWAL() throws Exception {
+    HRegionServer rs = TEST_UTIL.getMiniHBaseCluster().getRegionServer(0);
+    Configuration conf = rs.getConfiguration();
+    LogRoller logRoller = TEST_UTIL.getMiniHBaseCluster().getRegionServer(0).getWalRoller();
+    int originalSize = logRoller.getWalNeedsRoll().size();
+    FSHLog wal1 = new FSHLog(rs.getWALFileSystem(), rs.getWALRootDir(),
+        AbstractFSWALProvider.getWALDirectoryName(rs.getServerName().getServerName()), conf);
+    logRoller.addWAL(wal1);
+    FSHLog wal2 = new FSHLog(rs.getWALFileSystem(), rs.getWALRootDir(),
+      AbstractFSWALProvider.getWALDirectoryName(rs.getServerName().getServerName()), conf);
+    logRoller.addWAL(wal2);
+    FSHLog wal3 = new FSHLog(rs.getWALFileSystem(), rs.getWALRootDir(),
+      AbstractFSWALProvider.getWALDirectoryName(rs.getServerName().getServerName()), conf);
+    logRoller.addWAL(wal3);
+
+    assertEquals(originalSize + 3, logRoller.getWalNeedsRoll().size());
+    assertTrue(logRoller.getWalNeedsRoll().containsKey(wal1));
+
+    wal1.close();
+    Thread.sleep(2 * logRollPeriod);
+
+    assertEquals(originalSize + 2, logRoller.getWalNeedsRoll().size());
+    assertFalse(logRoller.getWalNeedsRoll().containsKey(wal1));
+
+    wal2.close();
+    wal3.close();
+    Thread.sleep(2 * logRollPeriod);
+
+    assertEquals(originalSize, logRoller.getWalNeedsRoll().size());
+  }
+}

hbase-server/src/test/java/org/apache/hadoop/hbase/regionserver/wal/AbstractTestFSWAL.java

@@ -473,4 +473,13 @@ public abstract class AbstractTestFSWAL {
       assertNull(key.getWriteEntry());
     }
   }
+
+  @Test(expected = WALClosedException.class)
+  public void testRollWriterForClosedWAL() throws IOException {
+    String testName = currentTest.getMethodName();
+    AbstractFSWAL<?> wal = newWAL(FS, CommonFSUtils.getWALRootDir(CONF), DIR.toString(), testName,
+      CONF, null, true, null, null);
+    wal.close();
+    wal.rollWriter();
+  }
 }