HBASE-26811 Secondary replica may be disabled for read forever (#4182)

hbase-client/src/main/java/org/apache/hadoop/hbase/client/TableDescriptorBuilder.java

@@ -1335,11 +1335,7 @@ public boolean hasRegionMemStoreReplication() {
      * @return the modifyable TD
      */
     public ModifyableTableDescriptor setRegionMemStoreReplication(boolean memstoreReplication) {
-      setValue(REGION_MEMSTORE_REPLICATION_KEY, Boolean.toString(memstoreReplication));
-      // If the memstore replication is setup, we do not have to wait for observing a flush event
-      // from primary before starting to serve reads, because gaps from replication is not applicable
-      return setValue(REGION_REPLICA_WAIT_FOR_PRIMARY_FLUSH_CONF_KEY,
-              Boolean.toString(memstoreReplication));
+      return setValue(REGION_MEMSTORE_REPLICATION_KEY, Boolean.toString(memstoreReplication));
     }
 
     public ModifyableTableDescriptor setPriority(int priority) {

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

@@ -23,6 +23,7 @@
 import static org.apache.hadoop.hbase.trace.HBaseSemanticAttributes.ROW_LOCK_READ_LOCK_KEY;
 import static org.apache.hadoop.hbase.util.ConcurrentMapUtils.computeIfAbsent;
 
+import com.google.errorprone.annotations.RestrictedApi;
 import edu.umd.cs.findbugs.annotations.Nullable;
 import io.opentelemetry.api.trace.Span;
 import java.io.EOFException;
@@ -8750,4 +8751,10 @@ public void addReadRequestsCount(long readRequestsCount) {
   public void addWriteRequestsCount(long writeRequestsCount) {
     this.writeRequestsCount.add(writeRequestsCount);
   }
+
+  @RestrictedApi(explanation = "Should only be called in tests", link = "",
+      allowedOnPath = ".*/src/test/.*")
+  boolean isReadsEnabled() {
+    return this.writestate.readsEnabled;
+  }
 }

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

@@ -2240,7 +2240,13 @@ private void triggerFlushInPrimaryRegion(final HRegion region) {
     }
     TableName tn = region.getTableDescriptor().getTableName();
     if (!ServerRegionReplicaUtil.isRegionReplicaReplicationEnabled(region.conf, tn) ||
-        !ServerRegionReplicaUtil.isRegionReplicaWaitForPrimaryFlushEnabled(region.conf)) {
+        !ServerRegionReplicaUtil.isRegionReplicaWaitForPrimaryFlushEnabled(region.conf) ||
+        // If the memstore replication not setup, we do not have to wait for observing a flush event
+        // from primary before starting to serve reads, because gaps from replication is not
+        // applicable,this logic is from
+        // TableDescriptorBuilder.ModifyableTableDescriptor.setRegionMemStoreReplication by
+        // HBASE-13063
+        !region.getTableDescriptor().hasRegionMemStoreReplication()) {
       region.setReadsEnabled(true);
       return;
     }

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

@@ -0,0 +1,124 @@
+/**
+ * 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.assertFalse;
+import static org.junit.Assert.assertNotNull;
+import static org.junit.Assert.assertNull;
+import static org.junit.Assert.assertTrue;
+import static org.junit.Assert.fail;
+
+import java.util.ArrayList;
+import java.util.Arrays;
+import java.util.List;
+import org.apache.hadoop.conf.Configuration;
+import org.apache.hadoop.hbase.HBaseClassTestRule;
+import org.apache.hadoop.hbase.HBaseTestingUtil;
+import org.apache.hadoop.hbase.StartTestingClusterOption;
+import org.apache.hadoop.hbase.TableName;
+import org.apache.hadoop.hbase.TableNameTestRule;
+import org.apache.hadoop.hbase.client.ColumnFamilyDescriptorBuilder;
+import org.apache.hadoop.hbase.client.TableDescriptor;
+import org.apache.hadoop.hbase.client.TableDescriptorBuilder;
+import org.apache.hadoop.hbase.executor.ExecutorType;
+import org.apache.hadoop.hbase.testclassification.MediumTests;
+import org.apache.hadoop.hbase.testclassification.RegionServerTests;
+import org.apache.hadoop.hbase.util.Bytes;
+import org.apache.hadoop.hbase.util.Pair;
+import org.apache.hadoop.hbase.util.ServerRegionReplicaUtil;
+import org.junit.AfterClass;
+import org.junit.BeforeClass;
+import org.junit.ClassRule;
+import org.junit.Rule;
+import org.junit.Test;
+import org.junit.experimental.categories.Category;
+
+@Category({ RegionServerTests.class, MediumTests.class })
+public class TestRegionReplicaWaitForPrimaryFlushConf {
+  @ClassRule
+  public static final HBaseClassTestRule CLASS_RULE =
+      HBaseClassTestRule.forClass(TestRegionReplicaWaitForPrimaryFlushConf.class);
+
+  private static final byte[] FAMILY = Bytes.toBytes("family_test");
+
+  private TableName tableName;
+
+  @Rule
+  public final TableNameTestRule name = new TableNameTestRule();
+  private static final HBaseTestingUtil HTU = new HBaseTestingUtil();
+
+  @BeforeClass
+  public static void setUpBeforeClass() throws Exception {
+    Configuration conf = HTU.getConfiguration();
+    conf.setBoolean(ServerRegionReplicaUtil.REGION_REPLICA_REPLICATION_CONF_KEY, true);
+    conf.setBoolean(ServerRegionReplicaUtil.REGION_REPLICA_WAIT_FOR_PRIMARY_FLUSH_CONF_KEY, false);
+    HTU.startMiniCluster(StartTestingClusterOption.builder().numRegionServers(2).build());
+
+  }
+
+  @AfterClass
+  public static void tearDownAfterClass() throws Exception {
+    HTU.shutdownMiniCluster();
+  }
+
+  /**
+   * This test is for HBASE-26811,when
+   * {@link ServerRegionReplicaUtil#REGION_REPLICA_WAIT_FOR_PRIMARY_FLUSH_CONF_KEY} is false and set
+   * {@link TableDescriptorBuilder#setRegionMemStoreReplication} to true explicitly,the secondary
+   * replica would be disabled for read after open.
+   */
+  @Test
+  public void testSecondaryReplicaReadEnabled() throws Exception {
+    tableName = name.getTableName();
+    TableDescriptor tableDescriptor = TableDescriptorBuilder.newBuilder(tableName)
+        .setRegionReplication(2).setColumnFamily(ColumnFamilyDescriptorBuilder.of(FAMILY))
+        .setRegionMemStoreReplication(true).build();
+    HTU.getAdmin().createTable(tableDescriptor);
+
+    final ArrayList<Pair<HRegion, HRegionServer>> regionAndRegionServers =
+        new ArrayList<Pair<HRegion, HRegionServer>>(Arrays.asList(null, null));
+
+    for (int i = 0; i < 2; i++) {
+      HRegionServer rs = HTU.getMiniHBaseCluster().getRegionServer(i);
+      List<HRegion> onlineRegions = rs.getRegions(tableName);
+      for (HRegion region : onlineRegions) {
+        int replicaId = region.getRegionInfo().getReplicaId();
+        assertNull(regionAndRegionServers.get(replicaId));
+        regionAndRegionServers.set(replicaId, new Pair<HRegion, HRegionServer>(region, rs));
+      }
+    }
+    for (Pair<HRegion, HRegionServer> pair : regionAndRegionServers) {
+      assertNotNull(pair);
+    }
+
+    HRegionServer secondaryRs = regionAndRegionServers.get(1).getSecond();
+
+    try {
+      secondaryRs.getExecutorService()
+          .getExecutorThreadPool(ExecutorType.RS_REGION_REPLICA_FLUSH_OPS);
+      fail();
+    } catch (NullPointerException e) {
+      assertTrue(e != null);
+    }
+    HRegion secondaryRegion = regionAndRegionServers.get(1).getFirst();
+    assertFalse(
+      ServerRegionReplicaUtil.isRegionReplicaWaitForPrimaryFlushEnabled(secondaryRegion.conf));
+    assertTrue(secondaryRegion.isReadsEnabled());
+  }
+
+}