Copilot commented on code in PR #10235:
URL: https://github.com/apache/ozone/pull/10235#discussion_r3223644399


##########
hadoop-ozone/integration-test/src/test/java/org/apache/hadoop/ozone/om/snapshot/TestOmSnapshotCheckpointDbContent.java:
##########
@@ -0,0 +1,241 @@
+/*
+ * 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.ozone.om.snapshot;
+
+import static org.apache.hadoop.ozone.OzoneConsts.OM_KEY_PREFIX;
+import static 
org.apache.hadoop.ozone.om.OMConfigKeys.OZONE_SNAPSHOT_DEFRAG_SERVICE_INTERVAL;
+import static org.apache.hadoop.ozone.om.codec.OMDBDefinition.BUCKET_TABLE;
+import static org.apache.hadoop.ozone.om.codec.OMDBDefinition.DIRECTORY_TABLE;
+import static org.apache.hadoop.ozone.om.codec.OMDBDefinition.FILE_TABLE;
+import static org.apache.hadoop.ozone.om.codec.OMDBDefinition.KEY_TABLE;
+import static 
org.apache.hadoop.ozone.om.codec.OMDBDefinition.MULTIPART_INFO_TABLE;
+import static org.apache.hadoop.ozone.om.codec.OMDBDefinition.OPEN_KEY_TABLE;
+import static org.apache.hadoop.ozone.om.codec.OMDBDefinition.VOLUME_TABLE;
+import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.junit.jupiter.api.Assertions.assertNotNull;
+
+import java.io.File;
+import java.io.IOException;
+import java.nio.file.Paths;
+import java.util.Arrays;
+import java.util.List;
+import java.util.SortedMap;
+import java.util.TreeMap;
+import java.util.concurrent.TimeoutException;
+import org.apache.hadoop.hdds.conf.OzoneConfiguration;
+import org.apache.hadoop.hdds.utils.IOUtils;
+import org.apache.hadoop.hdds.utils.db.RocksDBCheckpoint;
+import org.apache.hadoop.hdds.utils.db.Table;
+import org.apache.hadoop.hdds.utils.db.Table.KeyValue;
+import org.apache.hadoop.hdds.utils.db.Table.KeyValueIterator;
+import org.apache.hadoop.hdds.utils.db.TablePrefixInfo;
+import org.apache.hadoop.ozone.MiniOzoneCluster;
+import org.apache.hadoop.ozone.TestDataUtil;
+import org.apache.hadoop.ozone.client.ObjectStore;
+import org.apache.hadoop.ozone.client.OzoneBucket;
+import org.apache.hadoop.ozone.client.OzoneClient;
+import org.apache.hadoop.ozone.om.OMConfigKeys;
+import org.apache.hadoop.ozone.om.OMMetadataManager;
+import org.apache.hadoop.ozone.om.OmMetadataManagerImpl;
+import org.apache.hadoop.ozone.om.OmSnapshotManager;
+import org.apache.hadoop.ozone.om.OzoneManager;
+import org.apache.hadoop.ozone.om.helpers.BucketLayout;
+import org.apache.hadoop.ozone.om.helpers.SnapshotInfo;
+import org.apache.ozone.test.GenericTestUtils;
+import org.junit.jupiter.api.AfterAll;
+import org.junit.jupiter.api.BeforeAll;
+import org.junit.jupiter.api.Test;
+
+/**
+ * HDDS-13217: when an OM snapshot is created, the on-disk RocksDB checkpoint 
for that snapshot
+ * should contain the same bucket-scoped metadata as the live OM for the 
tables exercised here.
+ *
+ * <p>Flow: write some keys, call createSnapshot, wait until the checkpoint is 
materialized, open
+ * it read-only, then for each relevant table scan the key prefix for this 
volume/bucket on both
+ * the live metadata manager and the checkpoint and assert the maps match.
+ *
+ * <p>Tables compared: volume and bucket rows; key table for OBJECT_STORE and 
LEGACY layouts;
+ * file and directory tables for FILE_SYSTEM_OPTIMIZED; openKeyTable and 
multipartInfoTable (these
+ * stay empty in these tests but we still compare to catch stray open writes).
+ *
+ * <p>Omitted on purpose: snapshotInfoTable, because the new snapshot row is 
part of the same DB
+ * batch as the checkpoint step, so it appears on the live OM after the batch 
commits but not
+ * inside the checkpoint taken mid-batch. deletedTable, deletedDirTable, 
snapshotRenamedTable:
+ * the leader deletes those prefix ranges on the active DB immediately after 
the checkpoint, so
+ * live and checkpoint intentionally differ. We also do not scan cluster-wide 
tables (tokens,
+ * secrets, compaction log, other tenants/volumes).
+ *
+ * <p>Later tests worth adding: a second snapshot on the same bucket; writes 
after the snapshot to
+ * prove the checkpoint slice does not change; multipart uploads with real 
state; linked buckets
+ * resolving to a source bucket.
+ */
+public class TestOmSnapshotCheckpointDbContent {
+
+  private static final byte[] TEST_KEY_CONTENT = new byte[] {0x61, 0x62, 0x63};
+
+  private static MiniOzoneCluster cluster;
+  private static OzoneConfiguration conf;
+  private static OzoneClient client;
+  private static ObjectStore store;
+
+  /** Mini cluster shared by all tests: three datanodes, snapshots enabled; 
defrag disabled. */
+  @BeforeAll
+  public static void init()
+      throws IOException, InterruptedException, TimeoutException {
+    conf = new OzoneConfiguration();
+    conf.setBoolean(OMConfigKeys.OZONE_FILESYSTEM_SNAPSHOT_ENABLED_KEY, true);
+    conf.setInt(OZONE_SNAPSHOT_DEFRAG_SERVICE_INTERVAL, -1);
+
+    cluster = MiniOzoneCluster.newBuilder(conf).setNumDatanodes(3).build();
+    cluster.waitForClusterToBeReady();
+    client = cluster.newClient();
+    store = client.getObjectStore();
+  }
+
+  @AfterAll
+  public static void shutdown() {
+    IOUtils.closeQuietly(client);
+    if (cluster != null) {
+      cluster.shutdown();
+    }
+  }
+
+  /**
+   * Object store layout: mixed key shapes (flat and path-like), then snapshot 
and compare tables
+   * for this bucket.
+   */
+  @Test
+  public void testSnapshotCheckpointMatchesLiveObsBucket()
+      throws IOException, InterruptedException, TimeoutException {
+    runLayoutScenario(BucketLayout.OBJECT_STORE,
+        Arrays.asList("k1", "prefix/k2", "prefix/k3"));
+  }
+
+  /**
+   * File-system-optimized layout: data lives in file/dir tables; includes 
keys under a short path and
+   * one at the bucket root.
+   */
+  @Test
+  public void testSnapshotCheckpointMatchesLiveFsoBucket()
+      throws IOException, InterruptedException, TimeoutException {
+    runLayoutScenario(BucketLayout.FILE_SYSTEM_OPTIMIZED,
+        Arrays.asList("d/k1", "d/k2", "k-root"));
+  }
+
+  /**
+   * Legacy layout: still uses the key table only; flat key names to match 
default path behavior on
+   * this cluster.
+   */
+  @Test
+  public void testSnapshotCheckpointMatchesLiveLegacyBucket()
+      throws IOException, InterruptedException, TimeoutException {
+    runLayoutScenario(BucketLayout.LEGACY,
+        Arrays.asList("key-a", "key-b", "key-c"));
+  }
+
+  /** Create bucket, write keys, snapshot, wait for checkpoint files, open 
checkpoint DB, compare. */
+  private void runLayoutScenario(BucketLayout layout, List<String> keyNames)
+      throws IOException, InterruptedException, TimeoutException {
+    OzoneBucket bucket =
+        TestDataUtil.createVolumeAndBucket(client, layout);
+    String volumeName = bucket.getVolumeName();
+    String bucketName = bucket.getName();
+
+    for (String keyName : keyNames) {
+      TestDataUtil.createKey(bucket, keyName, TEST_KEY_CONTENT);
+    }
+
+    String snapshotName = "snap-a";
+    store.createSnapshot(volumeName, bucketName, snapshotName);
+
+    OzoneManager om = cluster.getOzoneManager();
+    OMMetadataManager liveMm = om.getMetadataManager();
+    SnapshotInfo snapshotInfo = liveMm.getSnapshotInfoTable().get(
+        SnapshotInfo.getTableKey(volumeName, bucketName, snapshotName));
+    assertNotNull(snapshotInfo, "Snapshot row should exist after 
createSnapshot");
+    assertEquals(snapshotName, snapshotInfo.getName());
+
+    String currentPath =
+        OmSnapshotManager.getSnapshotPath(conf, snapshotInfo, 0)
+            + OM_KEY_PREFIX + "CURRENT";
+    GenericTestUtils.waitFor(() -> new File(currentPath).exists(), 1000, 
120_000);
+
+    RocksDBCheckpoint checkpoint = new RocksDBCheckpoint(
+        Paths.get(OmSnapshotManager.getSnapshotPath(conf, snapshotInfo, 0)));
+    try (OmMetadataManagerImpl checkpointMm =
+             OmMetadataManagerImpl.createCheckpointMetadataManager(conf, 
checkpoint)) {
+      TablePrefixInfo prefixes = liveMm.getTableBucketPrefix(volumeName, 
bucketName);
+      assertBucketPrefixTablesMatch(liveMm, checkpointMm, prefixes, layout);
+    }
+  }
+
+  /** Load every row under the bucket prefix from live vs checkpoint for the 
tables this test cares about. */
+  private void assertBucketPrefixTablesMatch(
+      OMMetadataManager live,
+      OMMetadataManager checkpoint,
+      TablePrefixInfo prefixes,
+      BucketLayout layout) throws IOException {
+
+    assertPrefixEquals(VOLUME_TABLE, live.getVolumeTable(),
+        checkpoint.getVolumeTable(), prefixes);
+    assertPrefixEquals(BUCKET_TABLE, live.getBucketTable(),
+        checkpoint.getBucketTable(), prefixes);
+
+    if (layout.isFileSystemOptimized()) {
+      assertPrefixEquals(FILE_TABLE, live.getFileTable(),
+          checkpoint.getFileTable(), prefixes);
+      assertPrefixEquals(DIRECTORY_TABLE, live.getDirectoryTable(),
+          checkpoint.getDirectoryTable(), prefixes);
+    } else {
+      assertPrefixEquals(KEY_TABLE,
+          live.getKeyTable(layout),
+          checkpoint.getKeyTable(layout), prefixes);
+    }
+
+    assertPrefixEquals(OPEN_KEY_TABLE,
+        live.getOpenKeyTable(layout),
+        checkpoint.getOpenKeyTable(layout), prefixes);
+    assertPrefixEquals(MULTIPART_INFO_TABLE, live.getMultipartInfoTable(),
+        checkpoint.getMultipartInfoTable(), prefixes);
+  }
+
+  private static <V> void assertPrefixEquals(
+      String tableName,
+      Table<String, V> live,
+      Table<String, V> checkpoint,
+      TablePrefixInfo prefixes) throws IOException {
+    String prefix = prefixes.getTablePrefix(tableName);
+    assertEquals(readPrefix(live, prefix), readPrefix(checkpoint, prefix),
+        tableName);

Review Comment:
   If `prefixes.getTablePrefix(tableName)` returns `null` or empty, 
`readPrefix(...)` returns an empty map, and the assertion will pass even though 
the test didn’t validate anything for that table. Consider asserting the prefix 
is present (at least for the tables that are expected to be bucket-prefixed in 
this test) so missing/incorrect prefix computation fails loudly.



##########
hadoop-ozone/integration-test/src/test/java/org/apache/hadoop/ozone/om/snapshot/TestOmSnapshotCheckpointDbContent.java:
##########
@@ -0,0 +1,241 @@
+/*
+ * 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.ozone.om.snapshot;
+
+import static org.apache.hadoop.ozone.OzoneConsts.OM_KEY_PREFIX;
+import static 
org.apache.hadoop.ozone.om.OMConfigKeys.OZONE_SNAPSHOT_DEFRAG_SERVICE_INTERVAL;
+import static org.apache.hadoop.ozone.om.codec.OMDBDefinition.BUCKET_TABLE;
+import static org.apache.hadoop.ozone.om.codec.OMDBDefinition.DIRECTORY_TABLE;
+import static org.apache.hadoop.ozone.om.codec.OMDBDefinition.FILE_TABLE;
+import static org.apache.hadoop.ozone.om.codec.OMDBDefinition.KEY_TABLE;
+import static 
org.apache.hadoop.ozone.om.codec.OMDBDefinition.MULTIPART_INFO_TABLE;
+import static org.apache.hadoop.ozone.om.codec.OMDBDefinition.OPEN_KEY_TABLE;
+import static org.apache.hadoop.ozone.om.codec.OMDBDefinition.VOLUME_TABLE;
+import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.junit.jupiter.api.Assertions.assertNotNull;
+
+import java.io.File;
+import java.io.IOException;
+import java.nio.file.Paths;
+import java.util.Arrays;
+import java.util.List;
+import java.util.SortedMap;
+import java.util.TreeMap;
+import java.util.concurrent.TimeoutException;
+import org.apache.hadoop.hdds.conf.OzoneConfiguration;
+import org.apache.hadoop.hdds.utils.IOUtils;
+import org.apache.hadoop.hdds.utils.db.RocksDBCheckpoint;
+import org.apache.hadoop.hdds.utils.db.Table;
+import org.apache.hadoop.hdds.utils.db.Table.KeyValue;
+import org.apache.hadoop.hdds.utils.db.Table.KeyValueIterator;
+import org.apache.hadoop.hdds.utils.db.TablePrefixInfo;
+import org.apache.hadoop.ozone.MiniOzoneCluster;
+import org.apache.hadoop.ozone.TestDataUtil;
+import org.apache.hadoop.ozone.client.ObjectStore;
+import org.apache.hadoop.ozone.client.OzoneBucket;
+import org.apache.hadoop.ozone.client.OzoneClient;
+import org.apache.hadoop.ozone.om.OMConfigKeys;
+import org.apache.hadoop.ozone.om.OMMetadataManager;
+import org.apache.hadoop.ozone.om.OmMetadataManagerImpl;
+import org.apache.hadoop.ozone.om.OmSnapshotManager;
+import org.apache.hadoop.ozone.om.OzoneManager;
+import org.apache.hadoop.ozone.om.helpers.BucketLayout;
+import org.apache.hadoop.ozone.om.helpers.SnapshotInfo;
+import org.apache.ozone.test.GenericTestUtils;
+import org.junit.jupiter.api.AfterAll;
+import org.junit.jupiter.api.BeforeAll;
+import org.junit.jupiter.api.Test;
+
+/**
+ * HDDS-13217: when an OM snapshot is created, the on-disk RocksDB checkpoint 
for that snapshot
+ * should contain the same bucket-scoped metadata as the live OM for the 
tables exercised here.
+ *
+ * <p>Flow: write some keys, call createSnapshot, wait until the checkpoint is 
materialized, open
+ * it read-only, then for each relevant table scan the key prefix for this 
volume/bucket on both
+ * the live metadata manager and the checkpoint and assert the maps match.
+ *
+ * <p>Tables compared: volume and bucket rows; key table for OBJECT_STORE and 
LEGACY layouts;
+ * file and directory tables for FILE_SYSTEM_OPTIMIZED; openKeyTable and 
multipartInfoTable (these
+ * stay empty in these tests but we still compare to catch stray open writes).
+ *
+ * <p>Omitted on purpose: snapshotInfoTable, because the new snapshot row is 
part of the same DB
+ * batch as the checkpoint step, so it appears on the live OM after the batch 
commits but not
+ * inside the checkpoint taken mid-batch. deletedTable, deletedDirTable, 
snapshotRenamedTable:
+ * the leader deletes those prefix ranges on the active DB immediately after 
the checkpoint, so
+ * live and checkpoint intentionally differ. We also do not scan cluster-wide 
tables (tokens,
+ * secrets, compaction log, other tenants/volumes).
+ *
+ * <p>Later tests worth adding: a second snapshot on the same bucket; writes 
after the snapshot to
+ * prove the checkpoint slice does not change; multipart uploads with real 
state; linked buckets
+ * resolving to a source bucket.
+ */
+public class TestOmSnapshotCheckpointDbContent {
+
+  private static final byte[] TEST_KEY_CONTENT = new byte[] {0x61, 0x62, 0x63};
+
+  private static MiniOzoneCluster cluster;
+  private static OzoneConfiguration conf;
+  private static OzoneClient client;
+  private static ObjectStore store;
+
+  /** Mini cluster shared by all tests: three datanodes, snapshots enabled; 
defrag disabled. */
+  @BeforeAll
+  public static void init()
+      throws IOException, InterruptedException, TimeoutException {
+    conf = new OzoneConfiguration();
+    conf.setBoolean(OMConfigKeys.OZONE_FILESYSTEM_SNAPSHOT_ENABLED_KEY, true);
+    conf.setInt(OZONE_SNAPSHOT_DEFRAG_SERVICE_INTERVAL, -1);
+
+    cluster = MiniOzoneCluster.newBuilder(conf).setNumDatanodes(3).build();
+    cluster.waitForClusterToBeReady();
+    client = cluster.newClient();
+    store = client.getObjectStore();
+  }
+
+  @AfterAll
+  public static void shutdown() {
+    IOUtils.closeQuietly(client);
+    if (cluster != null) {
+      cluster.shutdown();
+    }
+  }
+
+  /**
+   * Object store layout: mixed key shapes (flat and path-like), then snapshot 
and compare tables
+   * for this bucket.
+   */
+  @Test
+  public void testSnapshotCheckpointMatchesLiveObsBucket()
+      throws IOException, InterruptedException, TimeoutException {
+    runLayoutScenario(BucketLayout.OBJECT_STORE,
+        Arrays.asList("k1", "prefix/k2", "prefix/k3"));
+  }
+
+  /**
+   * File-system-optimized layout: data lives in file/dir tables; includes 
keys under a short path and
+   * one at the bucket root.
+   */
+  @Test
+  public void testSnapshotCheckpointMatchesLiveFsoBucket()
+      throws IOException, InterruptedException, TimeoutException {
+    runLayoutScenario(BucketLayout.FILE_SYSTEM_OPTIMIZED,
+        Arrays.asList("d/k1", "d/k2", "k-root"));
+  }
+
+  /**
+   * Legacy layout: still uses the key table only; flat key names to match 
default path behavior on
+   * this cluster.
+   */
+  @Test
+  public void testSnapshotCheckpointMatchesLiveLegacyBucket()
+      throws IOException, InterruptedException, TimeoutException {
+    runLayoutScenario(BucketLayout.LEGACY,
+        Arrays.asList("key-a", "key-b", "key-c"));
+  }
+
+  /** Create bucket, write keys, snapshot, wait for checkpoint files, open 
checkpoint DB, compare. */
+  private void runLayoutScenario(BucketLayout layout, List<String> keyNames)
+      throws IOException, InterruptedException, TimeoutException {
+    OzoneBucket bucket =
+        TestDataUtil.createVolumeAndBucket(client, layout);
+    String volumeName = bucket.getVolumeName();
+    String bucketName = bucket.getName();
+
+    for (String keyName : keyNames) {
+      TestDataUtil.createKey(bucket, keyName, TEST_KEY_CONTENT);
+    }
+
+    String snapshotName = "snap-a";
+    store.createSnapshot(volumeName, bucketName, snapshotName);
+
+    OzoneManager om = cluster.getOzoneManager();
+    OMMetadataManager liveMm = om.getMetadataManager();
+    SnapshotInfo snapshotInfo = liveMm.getSnapshotInfoTable().get(
+        SnapshotInfo.getTableKey(volumeName, bucketName, snapshotName));
+    assertNotNull(snapshotInfo, "Snapshot row should exist after 
createSnapshot");
+    assertEquals(snapshotName, snapshotInfo.getName());
+
+    String currentPath =
+        OmSnapshotManager.getSnapshotPath(conf, snapshotInfo, 0)
+            + OM_KEY_PREFIX + "CURRENT";
+    GenericTestUtils.waitFor(() -> new File(currentPath).exists(), 1000, 
120_000);
+
+    RocksDBCheckpoint checkpoint = new RocksDBCheckpoint(
+        Paths.get(OmSnapshotManager.getSnapshotPath(conf, snapshotInfo, 0)));

Review Comment:
   Building `currentPath` via string concatenation is brittle (depends on 
whether `getSnapshotPath(...)` and `OM_KEY_PREFIX` include path separators) and 
repeats `getSnapshotPath(...)`. Prefer constructing a `Path` once (e.g., `Path 
snapshotPath = ...`) and resolving `OM_KEY_PREFIX` and `CURRENT` via 
`Path.resolve(...)` (or `Paths.get(...)`) to avoid separator issues and 
duplication.



##########
hadoop-ozone/integration-test/src/test/java/org/apache/hadoop/ozone/om/snapshot/TestOmSnapshotCheckpointDbContent.java:
##########
@@ -0,0 +1,241 @@
+/*
+ * 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.ozone.om.snapshot;
+
+import static org.apache.hadoop.ozone.OzoneConsts.OM_KEY_PREFIX;
+import static 
org.apache.hadoop.ozone.om.OMConfigKeys.OZONE_SNAPSHOT_DEFRAG_SERVICE_INTERVAL;
+import static org.apache.hadoop.ozone.om.codec.OMDBDefinition.BUCKET_TABLE;
+import static org.apache.hadoop.ozone.om.codec.OMDBDefinition.DIRECTORY_TABLE;
+import static org.apache.hadoop.ozone.om.codec.OMDBDefinition.FILE_TABLE;
+import static org.apache.hadoop.ozone.om.codec.OMDBDefinition.KEY_TABLE;
+import static 
org.apache.hadoop.ozone.om.codec.OMDBDefinition.MULTIPART_INFO_TABLE;
+import static org.apache.hadoop.ozone.om.codec.OMDBDefinition.OPEN_KEY_TABLE;
+import static org.apache.hadoop.ozone.om.codec.OMDBDefinition.VOLUME_TABLE;
+import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.junit.jupiter.api.Assertions.assertNotNull;
+
+import java.io.File;
+import java.io.IOException;
+import java.nio.file.Paths;
+import java.util.Arrays;
+import java.util.List;
+import java.util.SortedMap;
+import java.util.TreeMap;
+import java.util.concurrent.TimeoutException;
+import org.apache.hadoop.hdds.conf.OzoneConfiguration;
+import org.apache.hadoop.hdds.utils.IOUtils;
+import org.apache.hadoop.hdds.utils.db.RocksDBCheckpoint;
+import org.apache.hadoop.hdds.utils.db.Table;
+import org.apache.hadoop.hdds.utils.db.Table.KeyValue;
+import org.apache.hadoop.hdds.utils.db.Table.KeyValueIterator;
+import org.apache.hadoop.hdds.utils.db.TablePrefixInfo;
+import org.apache.hadoop.ozone.MiniOzoneCluster;
+import org.apache.hadoop.ozone.TestDataUtil;
+import org.apache.hadoop.ozone.client.ObjectStore;
+import org.apache.hadoop.ozone.client.OzoneBucket;
+import org.apache.hadoop.ozone.client.OzoneClient;
+import org.apache.hadoop.ozone.om.OMConfigKeys;
+import org.apache.hadoop.ozone.om.OMMetadataManager;
+import org.apache.hadoop.ozone.om.OmMetadataManagerImpl;
+import org.apache.hadoop.ozone.om.OmSnapshotManager;
+import org.apache.hadoop.ozone.om.OzoneManager;
+import org.apache.hadoop.ozone.om.helpers.BucketLayout;
+import org.apache.hadoop.ozone.om.helpers.SnapshotInfo;
+import org.apache.ozone.test.GenericTestUtils;
+import org.junit.jupiter.api.AfterAll;
+import org.junit.jupiter.api.BeforeAll;
+import org.junit.jupiter.api.Test;
+
+/**
+ * HDDS-13217: when an OM snapshot is created, the on-disk RocksDB checkpoint 
for that snapshot
+ * should contain the same bucket-scoped metadata as the live OM for the 
tables exercised here.
+ *
+ * <p>Flow: write some keys, call createSnapshot, wait until the checkpoint is 
materialized, open
+ * it read-only, then for each relevant table scan the key prefix for this 
volume/bucket on both
+ * the live metadata manager and the checkpoint and assert the maps match.
+ *
+ * <p>Tables compared: volume and bucket rows; key table for OBJECT_STORE and 
LEGACY layouts;
+ * file and directory tables for FILE_SYSTEM_OPTIMIZED; openKeyTable and 
multipartInfoTable (these
+ * stay empty in these tests but we still compare to catch stray open writes).
+ *
+ * <p>Omitted on purpose: snapshotInfoTable, because the new snapshot row is 
part of the same DB
+ * batch as the checkpoint step, so it appears on the live OM after the batch 
commits but not
+ * inside the checkpoint taken mid-batch. deletedTable, deletedDirTable, 
snapshotRenamedTable:
+ * the leader deletes those prefix ranges on the active DB immediately after 
the checkpoint, so
+ * live and checkpoint intentionally differ. We also do not scan cluster-wide 
tables (tokens,
+ * secrets, compaction log, other tenants/volumes).
+ *
+ * <p>Later tests worth adding: a second snapshot on the same bucket; writes 
after the snapshot to
+ * prove the checkpoint slice does not change; multipart uploads with real 
state; linked buckets
+ * resolving to a source bucket.
+ */
+public class TestOmSnapshotCheckpointDbContent {
+
+  private static final byte[] TEST_KEY_CONTENT = new byte[] {0x61, 0x62, 0x63};
+
+  private static MiniOzoneCluster cluster;
+  private static OzoneConfiguration conf;
+  private static OzoneClient client;
+  private static ObjectStore store;
+
+  /** Mini cluster shared by all tests: three datanodes, snapshots enabled; 
defrag disabled. */
+  @BeforeAll
+  public static void init()
+      throws IOException, InterruptedException, TimeoutException {
+    conf = new OzoneConfiguration();
+    conf.setBoolean(OMConfigKeys.OZONE_FILESYSTEM_SNAPSHOT_ENABLED_KEY, true);
+    conf.setInt(OZONE_SNAPSHOT_DEFRAG_SERVICE_INTERVAL, -1);
+
+    cluster = MiniOzoneCluster.newBuilder(conf).setNumDatanodes(3).build();
+    cluster.waitForClusterToBeReady();
+    client = cluster.newClient();
+    store = client.getObjectStore();
+  }
+
+  @AfterAll
+  public static void shutdown() {
+    IOUtils.closeQuietly(client);
+    if (cluster != null) {
+      cluster.shutdown();
+    }
+  }
+
+  /**
+   * Object store layout: mixed key shapes (flat and path-like), then snapshot 
and compare tables
+   * for this bucket.
+   */
+  @Test
+  public void testSnapshotCheckpointMatchesLiveObsBucket()
+      throws IOException, InterruptedException, TimeoutException {
+    runLayoutScenario(BucketLayout.OBJECT_STORE,
+        Arrays.asList("k1", "prefix/k2", "prefix/k3"));
+  }
+
+  /**
+   * File-system-optimized layout: data lives in file/dir tables; includes 
keys under a short path and
+   * one at the bucket root.
+   */
+  @Test
+  public void testSnapshotCheckpointMatchesLiveFsoBucket()
+      throws IOException, InterruptedException, TimeoutException {
+    runLayoutScenario(BucketLayout.FILE_SYSTEM_OPTIMIZED,
+        Arrays.asList("d/k1", "d/k2", "k-root"));
+  }
+
+  /**
+   * Legacy layout: still uses the key table only; flat key names to match 
default path behavior on
+   * this cluster.
+   */
+  @Test
+  public void testSnapshotCheckpointMatchesLiveLegacyBucket()
+      throws IOException, InterruptedException, TimeoutException {
+    runLayoutScenario(BucketLayout.LEGACY,
+        Arrays.asList("key-a", "key-b", "key-c"));
+  }
+
+  /** Create bucket, write keys, snapshot, wait for checkpoint files, open 
checkpoint DB, compare. */
+  private void runLayoutScenario(BucketLayout layout, List<String> keyNames)
+      throws IOException, InterruptedException, TimeoutException {
+    OzoneBucket bucket =
+        TestDataUtil.createVolumeAndBucket(client, layout);
+    String volumeName = bucket.getVolumeName();
+    String bucketName = bucket.getName();
+
+    for (String keyName : keyNames) {
+      TestDataUtil.createKey(bucket, keyName, TEST_KEY_CONTENT);
+    }
+
+    String snapshotName = "snap-a";
+    store.createSnapshot(volumeName, bucketName, snapshotName);
+
+    OzoneManager om = cluster.getOzoneManager();
+    OMMetadataManager liveMm = om.getMetadataManager();
+    SnapshotInfo snapshotInfo = liveMm.getSnapshotInfoTable().get(
+        SnapshotInfo.getTableKey(volumeName, bucketName, snapshotName));
+    assertNotNull(snapshotInfo, "Snapshot row should exist after 
createSnapshot");
+    assertEquals(snapshotName, snapshotInfo.getName());
+
+    String currentPath =
+        OmSnapshotManager.getSnapshotPath(conf, snapshotInfo, 0)
+            + OM_KEY_PREFIX + "CURRENT";
+    GenericTestUtils.waitFor(() -> new File(currentPath).exists(), 1000, 
120_000);
+
+    RocksDBCheckpoint checkpoint = new RocksDBCheckpoint(
+        Paths.get(OmSnapshotManager.getSnapshotPath(conf, snapshotInfo, 0)));
+    try (OmMetadataManagerImpl checkpointMm =
+             OmMetadataManagerImpl.createCheckpointMetadataManager(conf, 
checkpoint)) {
+      TablePrefixInfo prefixes = liveMm.getTableBucketPrefix(volumeName, 
bucketName);
+      assertBucketPrefixTablesMatch(liveMm, checkpointMm, prefixes, layout);
+    }
+  }
+
+  /** Load every row under the bucket prefix from live vs checkpoint for the 
tables this test cares about. */
+  private void assertBucketPrefixTablesMatch(
+      OMMetadataManager live,
+      OMMetadataManager checkpoint,
+      TablePrefixInfo prefixes,
+      BucketLayout layout) throws IOException {
+
+    assertPrefixEquals(VOLUME_TABLE, live.getVolumeTable(),
+        checkpoint.getVolumeTable(), prefixes);
+    assertPrefixEquals(BUCKET_TABLE, live.getBucketTable(),
+        checkpoint.getBucketTable(), prefixes);
+
+    if (layout.isFileSystemOptimized()) {
+      assertPrefixEquals(FILE_TABLE, live.getFileTable(),
+          checkpoint.getFileTable(), prefixes);
+      assertPrefixEquals(DIRECTORY_TABLE, live.getDirectoryTable(),
+          checkpoint.getDirectoryTable(), prefixes);
+    } else {
+      assertPrefixEquals(KEY_TABLE,
+          live.getKeyTable(layout),
+          checkpoint.getKeyTable(layout), prefixes);
+    }
+
+    assertPrefixEquals(OPEN_KEY_TABLE,
+        live.getOpenKeyTable(layout),
+        checkpoint.getOpenKeyTable(layout), prefixes);
+    assertPrefixEquals(MULTIPART_INFO_TABLE, live.getMultipartInfoTable(),
+        checkpoint.getMultipartInfoTable(), prefixes);
+  }
+
+  private static <V> void assertPrefixEquals(
+      String tableName,
+      Table<String, V> live,
+      Table<String, V> checkpoint,
+      TablePrefixInfo prefixes) throws IOException {
+    String prefix = prefixes.getTablePrefix(tableName);
+    assertEquals(readPrefix(live, prefix), readPrefix(checkpoint, prefix),
+        tableName);
+  }
+
+  private static <V> SortedMap<String, V> readPrefix(
+      Table<String, V> table, String prefix) throws IOException {
+    SortedMap<String, V> map = new TreeMap<>();
+    if (prefix == null || prefix.isEmpty()) {
+      return map;
+    }
+    try (KeyValueIterator<String, V> it = table.iterator(prefix)) {
+      while (it.hasNext()) {
+        KeyValue<String, V> kv = it.next();

Review Comment:
   `table.iterator(prefix)` commonly seeks to `prefix` but is not necessarily 
bounded to that prefix range. As written, this can read past the prefix and 
pull in unrelated rows (potentially the rest of the table), causing false 
failures and unnecessary work. Fix by stopping iteration once `kv.getKey()` no 
longer starts with `prefix` (or use an API that iterates over a bounded 
prefix/range if available).
   



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