HBASE-30368 TableSnapshotScanner fails on an already restored MOB tab…

hbase-mapreduce/src/main/java/org/apache/hadoop/hbase/mapreduce/TableSnapshotInputFormatImpl.java

@@ -363,7 +363,7 @@ public static List<RegionInfo> getRegionInfosFromManifest(SnapshotManifest manif
         continue;
       }
       // The mob region is a dummy region used only to organise mob files under mobdir. It has no
-      // region directory under the table dir to open, and holds no rows. See HBASE-30365.
+      // region directory under the table dir to open. See HBASE-30365.
       if (MobUtils.isMobRegionInfo(hri)) {
         continue;
       }

hbase-server/src/main/java/org/apache/hadoop/hbase/client/TableSnapshotScanner.java

@@ -26,6 +26,7 @@
 import org.apache.hadoop.fs.Path;
 import org.apache.hadoop.hbase.PrivateCellUtil;
 import org.apache.hadoop.hbase.client.metrics.ScanMetrics;
+import org.apache.hadoop.hbase.mob.MobUtils;
 import org.apache.hadoop.hbase.regionserver.MemStoreLAB;
 import org.apache.hadoop.hbase.snapshot.RestoreSnapshotHelper;
 import org.apache.hadoop.hbase.snapshot.SnapshotDescriptionUtils;
@@ -160,6 +161,11 @@ private boolean isValidRegion(RegionInfo hri) {
     if (hri.isOffline() && (hri.isSplit() || hri.isSplitParent())) {
       return false;
     }
+    // The mob region is a dummy region used only to organise mob files under mobdir. It has no
+    // region directory under the table dir to open. See HBASE-30365 and HBASE-30368.
+    if (MobUtils.isMobRegionInfo(hri)) {
+      return false;
+    }
     return PrivateCellUtil.overlappingKeys(scan.getStartRow(), scan.getStopRow(), hri.getStartKey(),
       hri.getEndKey());
   }

hbase-server/src/test/java/org/apache/hadoop/hbase/client/TestTableSnapshotScanner.java

@@ -49,6 +49,7 @@
 import org.apache.hadoop.hbase.regionserver.StoreContext;
 import org.apache.hadoop.hbase.regionserver.storefiletracker.StoreFileTracker;
 import org.apache.hadoop.hbase.regionserver.storefiletracker.StoreFileTrackerFactory;
+import org.apache.hadoop.hbase.snapshot.MobSnapshotTestingUtils;
 import org.apache.hadoop.hbase.snapshot.RestoreSnapshotHelper;
 import org.apache.hadoop.hbase.snapshot.SnapshotTestingUtils;
 import org.apache.hadoop.hbase.testclassification.ClientTests;
@@ -370,6 +371,31 @@ public void testScannerWithRestoreScanner() throws Exception {
     }
   }
 
+  @Test
+  public void testScannerWithRestoredMobSnapshot() throws Exception {
+    TableName tableName = TableName.valueOf(methodName);
+    String snapshotName = methodName + "Snapshot";
+    Path restoreDir = UTIL.getDataTestDirOnTestFS(snapshotName);
+    try {
+      MobSnapshotTestingUtils.createMobTable(UTIL, tableName, new byte[0][], 1, FAMILIES);
+      try (Table table = UTIL.getConnection().getTable(tableName)) {
+        UTIL.loadTable(table, FAMILIES);
+      }
+      UTIL.getAdmin().snapshot(snapshotName, tableName);
+
+      Configuration conf = UTIL.getConfiguration();
+      RestoreSnapshotHelper.copySnapshotForScanner(conf, fs, rootDir, restoreDir, snapshotName);
+      try (TableSnapshotScanner scanner = new TableSnapshotScanner(conf, rootDir, restoreDir,
+        snapshotName, new Scan().withStartRow(Bytes.toBytes("zzzz")), true)) {
+        assertNull(scanner.next());
+      }
+    } finally {
+      fs.delete(restoreDir, true);
+      UTIL.getAdmin().deleteSnapshot(snapshotName);
+      UTIL.deleteTable(tableName);
+    }
+  }
+
   private void testScanner(HBaseTestingUtil util, String snapshotName, int numRegions,
     boolean shutdownCluster) throws Exception {
     TableName tableName = TableName.valueOf("testScanner");