HBASE-28460 Full backup restore failed on empty HFiles (#5782)

Signed-off-by: Bryan Beaudreault <bbeaudreault@apache.org>

Author: DieterDP-ng

hbase-backup/src/main/java/org/apache/hadoop/hbase/backup/mapreduce/MapReduceRestoreJob.java

@@ -87,10 +87,7 @@ public void run(Path[] dirPaths, TableName[] tableNames, Path restoreRootDir,
             LOG.debug("Restoring HFiles from directory " + bulkOutputPath);
           }
 
-          if (loader.bulkLoad(newTableNames[i], bulkOutputPath).isEmpty()) {
-            throw new IOException("Can not restore from backup directory " + dirs
-              + " (check Hadoop and HBase logs). Bulk loader returns null");
-          }
+          loader.bulkLoad(newTableNames[i], bulkOutputPath);
         } else {
           throw new IOException("Can not restore from backup directory " + dirs
             + " (check Hadoop/MR and HBase logs). Player return code =" + result);

hbase-backup/src/main/java/org/apache/hadoop/hbase/backup/util/RestoreTool.java

@@ -61,7 +61,7 @@
  */
 @InterfaceAudience.Private
 public class RestoreTool {
-  public static final Logger LOG = LoggerFactory.getLogger(BackupUtils.class);
+  public static final Logger LOG = LoggerFactory.getLogger(RestoreTool.class);
   private final static long TABLE_AVAILABILITY_WAIT_TIME = 180000;
 
   private final String[] ignoreDirs = { HConstants.RECOVERED_EDITS_DIR };
@@ -437,6 +437,10 @@ byte[][] generateBoundaryKeys(ArrayList<Path> regionDirList) throws IOException
           HFile.Reader reader = HFile.createReader(fs, hfile, conf);
           final byte[] first, last;
           try {
+            if (reader.getEntries() == 0) {
+              LOG.debug("Skipping hfile with 0 entries: " + hfile);
+              continue;
+            }
             first = reader.getFirstRowKey().get();
             last = reader.getLastRowKey().get();
             LOG.debug("Trying to figure out region boundaries hfile=" + hfile + " first="
@@ -491,8 +495,12 @@ private void checkAndCreateTable(Connection conn, TableName targetTableName,
             admin.createTable(htd);
           } else {
             keys = generateBoundaryKeys(regionDirList);
-            // create table using table descriptor and region boundaries
-            admin.createTable(htd, keys);
+            if (keys.length > 0) {
+              // create table using table descriptor and region boundaries
+              admin.createTable(htd, keys);
+            } else {
+              admin.createTable(htd);
+            }
           }
         } catch (NamespaceNotFoundException e) {
           LOG.warn("There was no namespace and the same will be created");

hbase-backup/src/test/java/org/apache/hadoop/hbase/backup/TestFullRestore.java

@@ -27,6 +27,7 @@
 import org.apache.hadoop.hbase.TableName;
 import org.apache.hadoop.hbase.backup.util.BackupUtils;
 import org.apache.hadoop.hbase.client.Admin;
+import org.apache.hadoop.hbase.client.Table;
 import org.apache.hadoop.hbase.testclassification.LargeTests;
 import org.apache.hadoop.util.ToolRunner;
 import org.junit.ClassRule;
@@ -71,6 +72,43 @@ public void testFullRestoreSingle() throws Exception {
     hba.close();
   }
 
+  @Test
+  public void testFullRestoreSingleWithRegion() throws Exception {
+    LOG.info("test full restore on a single table empty table that has a region");
+
+    // This test creates its own table so other tests are not affected (we adjust it in this test)
+    TableName tableName = TableName.valueOf("table-full-restore-single-region");
+    TEST_UTIL.createTable(tableName, famName);
+
+    Admin admin = TEST_UTIL.getAdmin();
+
+    // Add & remove data to ensure a region is active, but functionally empty
+    Table table = TEST_UTIL.getConnection().getTable(tableName);
+    loadTable(table);
+    admin.flush(tableName);
+    TEST_UTIL.deleteTableData(tableName);
+    admin.flush(tableName);
+
+    TEST_UTIL.compact(tableName, true);
+
+    List<TableName> tables = Lists.newArrayList(tableName);
+    String backupId = fullTableBackup(tables);
+    assertTrue(checkSucceeded(backupId));
+
+    LOG.info("backup complete");
+
+    TEST_UTIL.deleteTable(tableName);
+
+    TableName[] tableset = new TableName[] { tableName };
+    TableName[] tablemap = new TableName[] { tableName };
+    BackupAdmin client = getBackupAdmin();
+    client.restore(BackupUtils.createRestoreRequest(BACKUP_ROOT_DIR, backupId, false, tableset,
+      tablemap, false));
+    assertTrue(admin.tableExists(tableName));
+    TEST_UTIL.deleteTable(tableName);
+    admin.close();
+  }
+
   @Test
   public void testFullRestoreSingleCommand() throws Exception {
     LOG.info("test full restore on a single table empty table: command-line");