HBASE-29729 Add per-region table descriptor hash to regionServer JMX Metrics

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

@@ -17,6 +17,7 @@
  */
 package org.apache.hadoop.hbase.client;
 
+import java.nio.ByteBuffer;
 import java.util.Arrays;
 import java.util.Collection;
 import java.util.Comparator;
@@ -25,10 +26,16 @@
 import java.util.Optional;
 import java.util.Set;
 import java.util.stream.Stream;
+import java.util.zip.CRC32;
 import org.apache.hadoop.hbase.HConstants;
 import org.apache.hadoop.hbase.TableName;
 import org.apache.hadoop.hbase.util.Bytes;
 import org.apache.yetus.audience.InterfaceAudience;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+
+import org.apache.hadoop.hbase.shaded.protobuf.ProtobufUtil;
+import org.apache.hadoop.hbase.shaded.protobuf.generated.HBaseProtos;
 
 /**
  * TableDescriptor contains the details about an HBase table such as the descriptors of all the
@@ -39,6 +46,8 @@
 @InterfaceAudience.Public
 public interface TableDescriptor {
 
+  Logger LOG = LoggerFactory.getLogger(TableDescriptor.class);
+
   @InterfaceAudience.Private
   Comparator<TableDescriptor> COMPARATOR = getComparator(ColumnFamilyDescriptor.COMPARATOR);
 
@@ -316,4 +325,22 @@ default boolean matchReplicationScope(boolean enabled) {
     }
     return !enabled;
   }
+
+  /**
+   * Computes a CRC32 hash of the table descriptor's protobuf representation. This hash can be used
+   * to detect changes in the table descriptor configuration.
+   * @return A hex string representation of the CRC32 hash, or "UNKNOWN" if computation fails
+   */
+  default String getDescriptorHash() {
+    try {
+      HBaseProtos.TableSchema tableSchema = ProtobufUtil.toTableSchema(this);
+      ByteBuffer byteBuffer = ByteBuffer.wrap(tableSchema.toByteArray());
+      CRC32 crc32 = new CRC32();
+      crc32.update(byteBuffer);
+      return Long.toHexString(crc32.getValue());
+    } catch (Exception e) {
+      LOG.error("Failed to compute table descriptor hash for table {}", getTableName(), e);
+      return "UNKNOWN";
+    }
+  }
 }

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

@@ -582,6 +582,11 @@ private static final class ModifyableTableDescriptor
     private final Map<byte[], ColumnFamilyDescriptor> families =
       new TreeMap<>(Bytes.BYTES_RAWCOMPARATOR);
 
+    /**
+     * Cached hash of the table descriptor. Computed lazily on first access.
+     */
+    private volatile String descriptorHash;
+
     /**
      * Construct a table descriptor specifying a TableName object
      * @param name Table name.
@@ -1510,6 +1515,14 @@ public Optional<String> getRegionServerGroup() {
         return Optional.empty();
       }
     }
+
+    @Override
+    public String getDescriptorHash() {
+      if (descriptorHash == null) {
+        descriptorHash = TableDescriptor.super.getDescriptorHash();
+      }
+      return descriptorHash;
+    }
   }
 
   /**

hbase-hadoop-compat/src/main/java/org/apache/hadoop/hbase/regionserver/MetricsRegionSource.java

@@ -56,6 +56,8 @@ public interface MetricsRegionSource extends Comparable<MetricsRegionSource> {
   String ROW_READS_ONLY_ON_MEMSTORE_DESC = "Row reads happening completely out of memstore";
   String MIXED_ROW_READS = "mixedRowReadsCount";
   String MIXED_ROW_READS_ON_STORE_DESC = "Row reads happening out of files and memstore on store";
+  String TABLE_DESCRIPTOR_HASH = "tableDescriptorHash";
+  String TABLE_DESCRIPTOR_HASH_DESC = "The hash of the current table descriptor";
 
   /**
    * Close the region's metrics as this region is closing.

hbase-hadoop-compat/src/main/java/org/apache/hadoop/hbase/regionserver/MetricsRegionSourceImpl.java

@@ -286,6 +286,9 @@ void snapshot(MetricsRecordBuilder mrb, boolean ignored) {
         MetricsRegionSource.ROW_READS_ONLY_ON_MEMSTORE_DESC);
       addCounter(mrb, this.regionWrapper.getMixedRowReadsCount(),
         MetricsRegionSource.MIXED_ROW_READS, MetricsRegionSource.MIXED_ROW_READS_ON_STORE_DESC);
+      mrb.add(Interns.tag(regionNamePrefix + MetricsRegionSource.TABLE_DESCRIPTOR_HASH,
+        MetricsRegionSource.TABLE_DESCRIPTOR_HASH_DESC,
+        this.regionWrapper.getTableDescriptorHash()));
     }
   }
 

hbase-hadoop-compat/src/main/java/org/apache/hadoop/hbase/regionserver/MetricsRegionWrapper.java

@@ -166,4 +166,12 @@ public interface MetricsRegionWrapper {
   /** Returns the number of row reads on memstore and file per store */
   Map<String, Long> getMixedRowReadsCount();
 
+  /**
+   * Returns a hash of the table descriptor that this region was opened with. This hash uniquely
+   * identifies the table configuration (column families, compression, TTL, block size, etc.) and
+   * can be used to determine if a region needs to be reopened to pick up descriptor changes.
+   * @return hex-encoded hash of the serialized TableDescriptor
+   */
+  String getTableDescriptorHash();
+
 }

hbase-hadoop-compat/src/test/java/org/apache/hadoop/hbase/regionserver/TestMetricsRegionSourceImpl.java

@@ -237,5 +237,10 @@ public Map<String, Long> getMixedRowReadsCount() {
       map.put("info", 0L);
       return map;
     }
+
+    @Override
+    public String getTableDescriptorHash() {
+      return "testhash";
+    }
   }
 }

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

@@ -64,9 +64,11 @@ public class MetricsRegionWrapperImpl implements MetricsRegionWrapper, Closeable
   private ScheduledFuture<?> regionMetricsUpdateTask;
 
   private float currentRegionCacheRatio;
+  private final String tableDescriptorHash;
 
   public MetricsRegionWrapperImpl(HRegion region) {
     this.region = region;
+    this.tableDescriptorHash = determineTableDescriptorHash();
     this.executor = CompatibilitySingletonFactory.getInstance(MetricsExecutor.class).getExecutor();
     this.runnable = new HRegionMetricsWrapperRunnable();
     this.regionMetricsUpdateTask =
@@ -357,6 +359,19 @@ public void run() {
     }
   }
 
+  @Override
+  public String getTableDescriptorHash() {
+    return tableDescriptorHash;
+  }
+
+  private String determineTableDescriptorHash() {
+    TableDescriptor tableDesc = this.region.getTableDescriptor();
+    if (tableDesc == null) {
+      return UNKNOWN;
+    }
+    return tableDesc.getDescriptorHash();
+  }
+
   @Override
   public void close() throws IOException {
     regionMetricsUpdateTask.cancel(true);

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

@@ -203,4 +203,9 @@ public Map<String, Long> getMixedRowReadsCount() {
     map.put("info", 0L);
     return map;
   }
+
+  @Override
+  public String getTableDescriptorHash() {
+    return "testhash123abc";
+  }
 }

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

@@ -0,0 +1,155 @@
+/*
+ * 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.assertNotEquals;
+import static org.junit.Assert.assertNotNull;
+
+import org.apache.hadoop.conf.Configuration;
+import org.apache.hadoop.fs.Path;
+import org.apache.hadoop.hbase.HBaseClassTestRule;
+import org.apache.hadoop.hbase.HBaseConfiguration;
+import org.apache.hadoop.hbase.HBaseTestingUtil;
+import org.apache.hadoop.hbase.TableName;
+import org.apache.hadoop.hbase.client.ColumnFamilyDescriptorBuilder;
+import org.apache.hadoop.hbase.client.RegionInfo;
+import org.apache.hadoop.hbase.client.RegionInfoBuilder;
+import org.apache.hadoop.hbase.client.TableDescriptor;
+import org.apache.hadoop.hbase.client.TableDescriptorBuilder;
+import org.apache.hadoop.hbase.testclassification.RegionServerTests;
+import org.apache.hadoop.hbase.testclassification.SmallTests;
+import org.apache.hadoop.hbase.util.Bytes;
+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, SmallTests.class })
+public class TestMetricsRegionWrapperTableDescriptorHash {
+
+  @ClassRule
+  public static final HBaseClassTestRule CLASS_RULE =
+    HBaseClassTestRule.forClass(TestMetricsRegionWrapperTableDescriptorHash.class);
+
+  private HBaseTestingUtil testUtil;
+  private Configuration conf;
+
+  @Before
+  public void setUp() throws Exception {
+    conf = HBaseConfiguration.create();
+    testUtil = new HBaseTestingUtil(conf);
+  }
+
+  @After
+  public void tearDown() throws Exception {
+    if (testUtil != null) {
+      testUtil.cleanupTestDir();
+    }
+  }
+
+  @Test
+  public void testTableDescriptorHashGeneration() throws Exception {
+    TableName tableName = TableName.valueOf("testTable");
+    TableDescriptor tableDescriptor = TableDescriptorBuilder.newBuilder(tableName)
+      .setColumnFamily(ColumnFamilyDescriptorBuilder.of("cf")).build();
+
+    RegionInfo regionInfo = RegionInfoBuilder.newBuilder(tableName).setStartKey(Bytes.toBytes("a"))
+      .setEndKey(Bytes.toBytes("z")).build();
+
+    Path testDir = testUtil.getDataTestDir("testTableDescriptorHashGeneration");
+    HRegion region =
+      HBaseTestingUtil.createRegionAndWAL(regionInfo, testDir, conf, tableDescriptor);
+
+    try (MetricsRegionWrapperImpl wrapper = new MetricsRegionWrapperImpl(region)) {
+      String hash = wrapper.getTableDescriptorHash();
+      assertNotNull(hash);
+      assertNotEquals("unknown", hash);
+      assertEquals(8, hash.length());
+    } finally {
+      HBaseTestingUtil.closeRegionAndWAL(region);
+    }
+  }
+
+  @Test
+  public void testHashConsistency() throws Exception {
+    TableName tableName = TableName.valueOf("testTable2");
+    TableDescriptor tableDescriptor = TableDescriptorBuilder.newBuilder(tableName)
+      .setColumnFamily(ColumnFamilyDescriptorBuilder.of("cf")).build();
+
+    RegionInfo regionInfo1 = RegionInfoBuilder.newBuilder(tableName).setStartKey(Bytes.toBytes("a"))
+      .setEndKey(Bytes.toBytes("m")).build();
+    RegionInfo regionInfo2 = RegionInfoBuilder.newBuilder(tableName).setStartKey(Bytes.toBytes("m"))
+      .setEndKey(Bytes.toBytes("z")).build();
+
+    Path testDir1 = testUtil.getDataTestDir("testHashConsistency1");
+    HRegion region1 =
+      HBaseTestingUtil.createRegionAndWAL(regionInfo1, testDir1, conf, tableDescriptor);
+
+    Path testDir2 = testUtil.getDataTestDir("testHashConsistency2");
+    HRegion region2 =
+      HBaseTestingUtil.createRegionAndWAL(regionInfo2, testDir2, conf, tableDescriptor);
+    try (MetricsRegionWrapperImpl wrapper1 = new MetricsRegionWrapperImpl(region1);
+      MetricsRegionWrapperImpl wrapper2 = new MetricsRegionWrapperImpl(region2)) {
+
+      String hash1 = wrapper1.getTableDescriptorHash();
+      String hash2 = wrapper2.getTableDescriptorHash();
+
+      assertEquals(hash1, hash2);
+    } finally {
+      HBaseTestingUtil.closeRegionAndWAL(region1);
+      HBaseTestingUtil.closeRegionAndWAL(region2);
+    }
+  }
+
+  @Test
+  public void testHashChangeOnDescriptorChange() throws Exception {
+    TableName tableName = TableName.valueOf("testTable3");
+    TableDescriptor tableDescriptor1 = TableDescriptorBuilder.newBuilder(tableName)
+      .setColumnFamily(ColumnFamilyDescriptorBuilder.of("cf")).build();
+    TableDescriptor tableDescriptor2 = TableDescriptorBuilder.newBuilder(tableName)
+      .setColumnFamily(
+        ColumnFamilyDescriptorBuilder.newBuilder("cf".getBytes()).setTimeToLive(86400).build())
+      .build();
+
+    RegionInfo regionInfo1 = RegionInfoBuilder.newBuilder(tableName).setStartKey(Bytes.toBytes("a"))
+      .setEndKey(Bytes.toBytes("m")).build();
+    RegionInfo regionInfo2 = RegionInfoBuilder.newBuilder(tableName).setStartKey(Bytes.toBytes("m"))
+      .setEndKey(Bytes.toBytes("z")).build();
+
+    Path testDir1 = testUtil.getDataTestDir("testHashChangeOnDescriptorChange1");
+    HRegion region1 =
+      HBaseTestingUtil.createRegionAndWAL(regionInfo1, testDir1, conf, tableDescriptor1);
+
+    Path testDir2 = testUtil.getDataTestDir("testHashChangeOnDescriptorChange2");
+    HRegion region2 =
+      HBaseTestingUtil.createRegionAndWAL(regionInfo2, testDir2, conf, tableDescriptor2);
+
+    try (MetricsRegionWrapperImpl wrapper1 = new MetricsRegionWrapperImpl(region1);
+      MetricsRegionWrapperImpl wrapper2 = new MetricsRegionWrapperImpl(region2)) {
+      String hash1 = wrapper1.getTableDescriptorHash();
+      String hash2 = wrapper2.getTableDescriptorHash();
+
+      assertNotEquals(hash1, hash2);
+    } finally {
+      HBaseTestingUtil.closeRegionAndWAL(region1);
+      HBaseTestingUtil.closeRegionAndWAL(region2);
+    }
+  }
+}

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

@@ -18,6 +18,7 @@
 package org.apache.hadoop.hbase.regionserver;
 
 import static org.junit.Assert.assertEquals;
+import static org.junit.Assert.assertNotEquals;
 import static org.junit.Assert.assertNotNull;
 import static org.junit.Assert.assertNull;
 import static org.junit.Assert.assertTrue;
@@ -598,4 +599,21 @@ public void testReadBytes() throws Exception {
     assertEquals("Total zero-byte read bytes should be equal to 0", 0,
       metricsRegionServer.getRegionServerWrapper().getZeroCopyBytesRead());
   }
+
+  @Test
+  public void testTableDescriptorHashMetric() throws Exception {
+    doNPuts(1, false);
+    metricsRegionServer.getRegionServerWrapper().forceRecompute();
+
+    HRegion region = rs.getRegions(tableName).get(0);
+    assertNotNull("Region should exist", region);
+
+    try (MetricsRegionWrapperImpl wrapper = new MetricsRegionWrapperImpl(region)) {
+      String hash = wrapper.getTableDescriptorHash();
+
+      assertNotNull("TableDescriptorHash should not be null", hash);
+      assertNotEquals("TableDescriptorHash should not be 'UNKNOWN'", "UNKNOWN", hash);
+      assertEquals("Hash should be 8 characters (CRC32 hex)", 8, hash.length());
+    }
+  }
 }