HBASE-27775 Use a separate WAL provider for hbase:replication table

hbase-replication/src/main/java/org/apache/hadoop/hbase/replication/ReplicationStorageFactory.java

@@ -102,4 +102,10 @@ public static ReplicationQueueStorage getReplicationQueueStorage(Connection conn
       return ReflectionUtils.newInstance(clazz, conf, tableName);
     }
   }
+
+  public static boolean isReplicationQueueTable(Configuration conf, TableName tableName) {
+    TableName replicationQueueTableName = TableName.valueOf(conf.get(REPLICATION_QUEUE_TABLE_NAME,
+      REPLICATION_QUEUE_TABLE_NAME_DEFAULT.getNameAsString()));
+    return replicationQueueTableName.equals(tableName);
+  }
 }

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

@@ -982,12 +982,12 @@ synchronized public void run() {
 
         lastRan = currentTime;
 
-        final WALProvider provider = regionServer.getWalFactory().getWALProvider();
-        final WALProvider metaProvider = regionServer.getWalFactory().getMetaWALProvider();
-        numWALFiles = (provider == null ? 0 : provider.getNumLogFiles())
-          + (metaProvider == null ? 0 : metaProvider.getNumLogFiles());
-        walFileSize = (provider == null ? 0 : provider.getLogFileSize())
-          + (metaProvider == null ? 0 : metaProvider.getLogFileSize());
+        List<WALProvider> providers = regionServer.getWalFactory().getAllWALProviders();
+        for (WALProvider provider : providers) {
+          numWALFiles += provider.getNumLogFiles();
+          walFileSize += provider.getLogFileSize();
+        }
+
         // Copy over computed values so that no thread sees half computed values.
         numStores = tempNumStores;
         numStoreFiles = tempNumStoreFiles;

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

@@ -0,0 +1,108 @@
+/*
+ * 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.wal;
+
+import java.io.Closeable;
+import java.io.IOException;
+import java.util.concurrent.atomic.AtomicReference;
+import org.apache.hadoop.conf.Configuration;
+import org.apache.hadoop.hbase.Abortable;
+import org.apache.hadoop.hbase.regionserver.wal.MetricsWAL;
+import org.apache.hadoop.hbase.wal.WALFactory.Providers;
+import org.apache.yetus.audience.InterfaceAudience;
+
+/**
+ * A lazy initialized WAL provider for holding the WALProvider for some special tables, such as
+ * hbase:meta, hbase:replication, etc.
+ */
+@InterfaceAudience.Private
+class LazyInitializedWALProvider implements Closeable {
+
+  private final WALFactory factory;
+
+  private final String providerId;
+
+  private final String providerConfigName;
+
+  private final Abortable abortable;
+
+  private final AtomicReference<WALProvider> holder = new AtomicReference<>();
+
+  LazyInitializedWALProvider(WALFactory factory, String providerId, String providerConfigName,
+    Abortable abortable) {
+    this.factory = factory;
+    this.providerId = providerId;
+    this.providerConfigName = providerConfigName;
+    this.abortable = abortable;
+  }
+
+  WALProvider getProvider() throws IOException {
+    Configuration conf = factory.getConf();
+    for (;;) {
+      WALProvider provider = this.holder.get();
+      if (provider != null) {
+        return provider;
+      }
+      Class<? extends WALProvider> clz = null;
+      if (conf.get(providerConfigName) == null) {
+        try {
+          clz = conf.getClass(WALFactory.WAL_PROVIDER, Providers.defaultProvider.clazz,
+            WALProvider.class);
+        } catch (Throwable t) {
+          // the WAL provider should be an enum. Proceed
+        }
+      }
+      if (clz == null) {
+        clz = factory.getProviderClass(providerConfigName,
+          conf.get(WALFactory.WAL_PROVIDER, WALFactory.DEFAULT_WAL_PROVIDER));
+      }
+      provider = WALFactory.createProvider(clz);
+      provider.init(factory, conf, providerId, this.abortable);
+      provider.addWALActionsListener(new MetricsWAL());
+      if (this.holder.compareAndSet(null, provider)) {
+        return provider;
+      } else {
+        // someone is ahead of us, close and try again.
+        provider.close();
+      }
+    }
+  }
+
+  /**
+   * Get the provider if it already initialized, otherwise just return {@code null} instead of
+   * creating it.
+   */
+  WALProvider getProviderNoCreate() {
+    return holder.get();
+  }
+
+  @Override
+  public void close() throws IOException {
+    WALProvider provider = this.holder.get();
+    if (provider != null) {
+      provider.close();
+    }
+  }
+
+  void shutdown() throws IOException {
+    WALProvider provider = this.holder.get();
+    if (provider != null) {
+      provider.shutdown();
+    }
+  }
+}