HBASE-20649 Validate HFiles do not have PREFIX_TREE DataBlockEncoding

Amending-Author: Balazs Meszaros <balazs.meszaros@cloudera.com>

Signed-off-by: Sean Busbey <busbey@apache.org>

hbase-server/src/main/java/org/apache/hadoop/hbase/tool/DataBlockEncodingValidator.java

@@ -76,9 +76,8 @@ public class DataBlockEncodingValidator extends AbstractHBaseTool {
 
     if (incompatibilities > 0) {
       LOG.warn("There are {} column families with incompatible Data Block Encodings. Do not "
-          + "upgrade until these encodings are converted to a supported one.", incompatibilities);
+          + "upgrade until these encodings are converted to a supported one. "
-      LOG.warn("Check http://hbase.apache.org/book.html#upgrade2.0.prefix-tree.removed "
+          + "Check https://s.apache.org/prefixtree for instructions.", incompatibilities);
-          + "for instructions.");
     } else {
       LOG.info("The used Data Block Encodings are compatible with HBase 2.0.");
     }

hbase-server/src/main/java/org/apache/hadoop/hbase/tool/HFileContentValidator.java

@@ -0,0 +1,126 @@
+/**
+ *
+ * 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.tool;
+
+import java.io.IOException;
+import java.util.Collection;
+import java.util.List;
+import java.util.concurrent.ExecutorService;
+import java.util.concurrent.Executors;
+import java.util.concurrent.TimeUnit;
+
+import org.apache.hadoop.conf.Configuration;
+import org.apache.hadoop.fs.FileSystem;
+import org.apache.hadoop.fs.Path;
+import org.apache.hadoop.hbase.HBaseInterfaceAudience;
+import org.apache.hadoop.hbase.HConstants;
+import org.apache.hadoop.hbase.util.AbstractHBaseTool;
+import org.apache.hadoop.hbase.util.FSUtils;
+import org.apache.hadoop.hbase.util.Threads;
+import org.apache.hadoop.hbase.util.hbck.HFileCorruptionChecker;
+import org.apache.yetus.audience.InterfaceAudience;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+
+import org.apache.hbase.thirdparty.org.apache.commons.cli.CommandLine;
+
+@InterfaceAudience.LimitedPrivate(HBaseInterfaceAudience.TOOLS)
+public class HFileContentValidator extends AbstractHBaseTool {
+
+  private static final Logger LOG = LoggerFactory.getLogger(HFileContentValidator.class);
+
+  /**
+   * Check HFile contents are readable by HBase 2.
+   *
+   * @param conf used configuration
+   * @return number of HFiles corrupted HBase
+   * @throws IOException if a remote or network exception occurs
+   */
+  private boolean validateHFileContent(Configuration conf) throws IOException {
+    FileSystem fileSystem = FSUtils.getCurrentFileSystem(conf);
+
+    ExecutorService threadPool = createThreadPool(conf);
+    HFileCorruptionChecker checker;
+
+    try {
+      checker = new HFileCorruptionChecker(conf, threadPool, false);
+
+      Path rootDir = FSUtils.getRootDir(conf);
+      LOG.info("Validating HFile contents under {}", rootDir);
+
+      Collection<Path> tableDirs = FSUtils.getTableDirs(fileSystem, rootDir);
+      checker.checkTables(tableDirs);
+
+      Path archiveRootDir = new Path(rootDir, HConstants.HFILE_ARCHIVE_DIRECTORY);
+      LOG.info("Validating HFile contents under {}", archiveRootDir);
+
+      List<Path> archiveTableDirs = FSUtils.getTableDirs(fileSystem, archiveRootDir);
+      checker.checkTables(archiveTableDirs);
+    } finally {
+      threadPool.shutdown();
+
+      try {
+        threadPool.awaitTermination(Long.MAX_VALUE, TimeUnit.SECONDS);
+      } catch (InterruptedException e) {
+        Thread.currentThread().interrupt();
+      }
+    }
+
+    int checkedFiles = checker.getHFilesChecked();
+    Collection<Path> corrupted = checker.getCorrupted();
+
+    if (corrupted.isEmpty()) {
+      LOG.info("Checked {} HFiles, none of them are corrupted.", checkedFiles);
+      LOG.info("There are no incompatible HFiles.");
+
+      return true;
+    } else {
+      LOG.info("Checked {} HFiles, {} are corrupted.", checkedFiles, corrupted.size());
+
+      for (Path path : corrupted) {
+        LOG.info("Corrupted file: {}", path);
+      }
+
+      LOG.info("Change data block encodings before upgrading. "
+          + "Check https://s.apache.org/prefixtree for instructions.");
+
+      return false;
+    }
+  }
+
+  private ExecutorService createThreadPool(Configuration conf) {
+    int availableProcessors = Runtime.getRuntime().availableProcessors();
+    int numThreads = conf.getInt("hfilevalidator.numthreads", availableProcessors);
+    return Executors.newFixedThreadPool(numThreads,
+        Threads.getNamedThreadFactory("hfile-validator"));
+  }
+
+  @Override
+  protected void addOptions() {
+  }
+
+  @Override
+  protected void processOptions(CommandLine cmd) {
+  }
+
+  @Override
+  protected int doWork() throws Exception {
+    return (validateHFileContent(getConf())) ? EXIT_SUCCESS : EXIT_FAILURE;
+  }
+}

hbase-server/src/main/java/org/apache/hadoop/hbase/tool/PreUpgradeValidator.java

@@ -38,6 +38,7 @@ import org.slf4j.LoggerFactory;
  * <ul>
  * <li>validate-cp: Validates Co-processors compatibility</li>
  * <li>validate-dbe: Check Data Block Encoding for column families</li>
+ * <li>validate-hfile: Check for corrupted HFiles</li>
  * </ul>
  * </p>
  */
@@ -49,6 +50,7 @@ public class PreUpgradeValidator implements Tool {
   public static final String TOOL_NAME = "pre-upgrade";
   public static final String VALIDATE_CP_NAME = "validate-cp";
   public static final String VALIDATE_DBE_NAME = "validate-dbe";
+  public static final String VALIDATE_HFILE = "validate-hfile";
 
   private Configuration configuration;
 
@@ -69,6 +71,8 @@ public class PreUpgradeValidator implements Tool {
         VALIDATE_CP_NAME);
     System.out.printf(" %-15s Validate DataBlockEncodings are compatible with HBase%n",
         VALIDATE_DBE_NAME);
+    System.out.printf(" %-15s Validate HFile contents are readable%n",
+        VALIDATE_HFILE);
     System.out.println("For further information, please use command -h");
   }
 
@@ -88,6 +92,9 @@ public class PreUpgradeValidator implements Tool {
       case VALIDATE_DBE_NAME:
         tool = new DataBlockEncodingValidator();
         break;
+      case VALIDATE_HFILE:
+        tool = new HFileContentValidator();
+        break;
       case "-h":
         printUsage();
         return AbstractHBaseTool.EXIT_FAILURE;

src/main/asciidoc/_chapters/ops_mgt.adoc

@@ -898,7 +898,8 @@ $ bin/hbase pre-upgrade validate-cp -table .*
 It validates every table level co-processors where the table name matches to `.*` regular expression.
 
 ==== DataBlockEncoding validation
-HBase 2.0 removed `PREFIX_TREE` Data Block Encoding from column families.
+HBase 2.0 removed `PREFIX_TREE` Data Block Encoding from column families. For further information
+please check <<upgrade2.0.prefix-tree.removed,_prefix-tree_ encoding removed>>.
 To verify that none of the column families are using incompatible Data Block Encodings in the cluster run the following command.
 
 [source, bash]
@@ -906,8 +907,103 @@ To verify that none of the column families are using incompatible Data Block Enc
 $ bin/hbase pre-upgrade validate-dbe
 ----
 
-This check validates all column families and print out any incompatibilities.
+This check validates all column families and print out any incompatibilities. For example:
-To change `PREFIX_TREE` encoding to supported one check <<upgrade2.0.prefix-tree.removed,_prefix-tree_ encoding removed>>.
+
+----
+2018-07-13 09:58:32,028 WARN  [main] tool.DataBlockEncodingValidator: Incompatible DataBlockEncoding for table: t, cf: f, encoding: PREFIX_TREE
+----
+
+Which means that Data Block Encoding of table `t`, column family `f` is incompatible. To fix, use `alter` command in HBase shell:
+
+----
+alter 't', { NAME => 'f', DATA_BLOCK_ENCODING => 'FAST_DIFF' }
+----
+
+Please also validate HFiles, which is described in the next section.
+
+==== HFile Content validation
+Even though Data Block Encoding is changed from `PREFIX_TREE` it is still possible to have HFiles that contain data encoded that way.
+To verify that HFiles are readable with HBase 2 please use _HFile content validator_.
+
+[source, bash]
+----
+$ bin/hbase pre-upgrade validate-hfile
+----
+
+The tool will log the corrupt HFiles and details about the root cause.
+If the problem is about PREFIX_TREE encoding it is necessary to change encodings before upgrading to HBase 2.
+
+The following log message shows an example of incorrect HFiles.
+
+----
+2018-06-05 16:20:46,976 WARN  [hfilevalidator-pool1-t3] hbck.HFileCorruptionChecker: Found corrupt HFile hdfs://example.com:8020/hbase/data/default/t/72ea7f7d625ee30f959897d1a3e2c350/prefix/7e6b3d73263c4851bf2b8590a9b3791e
+org.apache.hadoop.hbase.io.hfile.CorruptHFileException: Problem reading HFile Trailer from file hdfs://example.com:8020/hbase/data/default/t/72ea7f7d625ee30f959897d1a3e2c350/prefix/7e6b3d73263c4851bf2b8590a9b3791e
+    ...
+Caused by: java.io.IOException: Invalid data block encoding type in file info: PREFIX_TREE
+    ...
+Caused by: java.lang.IllegalArgumentException: No enum constant org.apache.hadoop.hbase.io.encoding.DataBlockEncoding.PREFIX_TREE
+    ...
+2018-06-05 16:20:47,322 INFO  [main] tool.HFileContentValidator: Corrupted file: hdfs://example.com:8020/hbase/data/default/t/72ea7f7d625ee30f959897d1a3e2c350/prefix/7e6b3d73263c4851bf2b8590a9b3791e
+2018-06-05 16:20:47,383 INFO  [main] tool.HFileContentValidator: Corrupted file: hdfs://example.com:8020/hbase/archive/data/default/t/56be41796340b757eb7fff1eb5e2a905/f/29c641ae91c34fc3bee881f45436b6d1
+----
+
+===== Fixing PREFIX_TREE errors
+
+It's possible to get `PREFIX_TREE` errors after changing Data Block Encoding to a supported one. It can happen
+because there are some HFiles which still encoded with `PREFIX_TREE` or there are still some snapshots.
+
+For fixing HFiles, please run a major compaction on the table (it was `default:t` according to the log message):
+
+----
+major_compact 't'
+----
+
+HFiles can be referenced from snapshots, too. It's the case when the HFile is located under `archive/data`.
+The first step is to determine which snapshot references that HFile (the name of the file was `29c641ae91c34fc3bee881f45436b6d1`
+according to the logs):
+
+[source, bash]
+----
+for snapshot in $(hbase snapshotinfo -list-snapshots 2> /dev/null | tail -n -1 | cut -f 1 -d \|);
+do
+  echo "checking snapshot named '${snapshot}'";
+  hbase snapshotinfo -snapshot "${snapshot}" -files 2> /dev/null | grep 29c641ae91c34fc3bee881f45436b6d1;
+done
+----
+
+The output of this shell script is:
+
+----
+checking snapshot named 't_snap'
+   1.0 K t/56be41796340b757eb7fff1eb5e2a905/f/29c641ae91c34fc3bee881f45436b6d1 (archive)
+----
+
+Which means `t_snap` snapshot references the incompatible HFile. If the snapshot is still needed,
+then it has to be recreated with HBase shell:
+
+----
+# creating a new namespace for the cleanup process
+create_namespace 'pre_upgrade_cleanup'
+
+# creating a new snapshot
+clone_snapshot 't_snap', 'pre_upgrade_cleanup:t'
+alter 'pre_upgrade_cleanup:t', { NAME => 'f', DATA_BLOCK_ENCODING => 'FAST_DIFF' }
+major_compact 'pre_upgrade_cleanup:t'
+
+# removing the invalid snapshot
+delete_snapshot 't_snap'
+
+# creating a new snapshot
+snapshot 'pre_upgrade_cleanup:t', 't_snap'
+
+# removing temporary table
+disable 'pre_upgrade_cleanup:t'
+drop 'pre_upgrade_cleanup:t'
+drop_namespace 'pre_upgrade_cleanup'
+----
+
+For further information, please refer to
+link:https://issues.apache.org/jira/browse/HBASE-20649?focusedCommentId=16535476#comment-16535476[HBASE-20649].
 
 [[ops.regionmgt]]
 == Region Management