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1   /**
2    *
3    * Licensed to the Apache Software Foundation (ASF) under one
4    * or more contributor license agreements.  See the NOTICE file
5    * distributed with this work for additional information
6    * regarding copyright ownership.  The ASF licenses this file
7    * to you under the Apache License, Version 2.0 (the
8    * "License"); you may not use this file except in compliance
9    * with the License.  You may obtain a copy of the License at
10   *
11   *     http://www.apache.org/licenses/LICENSE-2.0
12   *
13   * Unless required by applicable law or agreed to in writing, software
14   * distributed under the License is distributed on an "AS IS" BASIS,
15   * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
16   * See the License for the specific language governing permissions and
17   * limitations under the License.
18   */
19  package org.apache.hadoop.hbase.master.handler;
20  
21  import java.io.IOException;
22  import java.util.List;
23  
24  import org.apache.commons.logging.Log;
25  import org.apache.commons.logging.LogFactory;
26  import org.apache.hadoop.classification.InterfaceAudience;
27  import org.apache.hadoop.fs.FileSystem;
28  import org.apache.hadoop.fs.Path;
29  import org.apache.hadoop.hbase.HRegionInfo;
30  import org.apache.hadoop.hbase.Server;
31  import org.apache.hadoop.hbase.backup.HFileArchiver;
32  import org.apache.hadoop.hbase.catalog.MetaEditor;
33  import org.apache.hadoop.hbase.executor.EventType;
34  import org.apache.hadoop.hbase.master.AssignmentManager;
35  import org.apache.hadoop.hbase.master.HMaster;
36  import org.apache.hadoop.hbase.master.MasterCoprocessorHost;
37  import org.apache.hadoop.hbase.master.MasterFileSystem;
38  import org.apache.hadoop.hbase.master.MasterServices;
39  import org.apache.hadoop.hbase.master.RegionStates;
40  import org.apache.hadoop.hbase.util.Bytes;
41  import org.apache.hadoop.hbase.util.Threads;
42  import org.apache.zookeeper.KeeperException;
43  
44  @InterfaceAudience.Private
45  public class DeleteTableHandler extends TableEventHandler {
46    private static final Log LOG = LogFactory.getLog(DeleteTableHandler.class);
47  
48    public DeleteTableHandler(byte [] tableName, Server server,
49        final MasterServices masterServices) {
50      super(EventType.C_M_DELETE_TABLE, tableName, server, masterServices);
51    }
52  
53    @Override
54    protected void prepareWithTableLock() throws IOException {
55      // The next call fails if no such table.
56      getTableDescriptor();
57    }
58  
59    @Override
60    protected void handleTableOperation(List<HRegionInfo> regions)
61    throws IOException, KeeperException {
62      MasterCoprocessorHost cpHost = ((HMaster) this.server)
63          .getCoprocessorHost();
64      if (cpHost != null) {
65        cpHost.preDeleteTableHandler(this.tableName);
66      }
67  
68      // 1. Wait because of region in transition
69      AssignmentManager am = this.masterServices.getAssignmentManager();
70      RegionStates states = am.getRegionStates();
71      long waitTime = server.getConfiguration().
72        getLong("hbase.master.wait.on.region", 5 * 60 * 1000);
73      for (HRegionInfo region : regions) {
74        long done = System.currentTimeMillis() + waitTime;
75        while (System.currentTimeMillis() < done) {
76          if (states.isRegionFailedToOpen(region)) {
77            am.regionOffline(region);
78          }
79          if (!states.isRegionInTransition(region)) break;
80          Threads.sleep(waitingTimeForEvents);
81          LOG.debug("Waiting on region to clear regions in transition; "
82            + am.getRegionStates().getRegionTransitionState(region));
83        }
84        if (states.isRegionInTransition(region)) {
85          throw new IOException("Waited hbase.master.wait.on.region (" +
86            waitTime + "ms) for region to leave region " +
87            region.getRegionNameAsString() + " in transitions");
88        }
89      }
90  
91      // 2. Remove regions from META
92      LOG.debug("Deleting regions from META");
93      MetaEditor.deleteRegions(this.server.getCatalogTracker(), regions);
94  
95      // 3. Move the table in /hbase/.tmp
96      MasterFileSystem mfs = this.masterServices.getMasterFileSystem();
97      Path tempTableDir = mfs.moveTableToTemp(tableName);
98  
99      try {
100       // 4. Delete regions from FS (temp directory)
101       FileSystem fs = mfs.getFileSystem();
102       for (HRegionInfo hri: regions) {
103         LOG.debug("Archiving region " + hri.getRegionNameAsString() + " from FS");
104         HFileArchiver.archiveRegion(fs, mfs.getRootDir(),
105             tempTableDir, new Path(tempTableDir, hri.getEncodedName()));
106       }
107 
108       // 5. Delete table from FS (temp directory)
109       if (!fs.delete(tempTableDir, true)) {
110         LOG.error("Couldn't delete " + tempTableDir);
111       }
112 
113       LOG.debug("Table '" + Bytes.toString(tableName) + "' archived!");
114     } finally {
115       String tableNameStr = Bytes.toString(tableName);
116       // 6. Update table descriptor cache
117       LOG.debug("Removing '" + tableNameStr + "' descriptor.");
118       this.masterServices.getTableDescriptors().remove(Bytes.toString(tableName));
119 
120       // 7. If entry for this table in zk, and up in AssignmentManager, remove it.
121       LOG.debug("Marking '" + tableNameStr + "' as deleted.");
122       am.getZKTable().setDeletedTable(tableNameStr);
123     }
124 
125     if (cpHost != null) {
126       cpHost.postDeleteTableHandler(this.tableName);
127     }
128   }
129 
130   @Override
131   protected void releaseTableLock() {
132     super.releaseTableLock();
133     try {
134       masterServices.getTableLockManager().tableDeleted(tableName);
135     } catch (IOException ex) {
136       LOG.warn("Received exception from TableLockManager.tableDeleted:", ex); //not critical
137     }
138   }
139 
140   @Override
141   public String toString() {
142     String name = "UnknownServerName";
143     if(server != null && server.getServerName() != null) {
144       name = server.getServerName().toString();
145     }
146     return getClass().getSimpleName() + "-" + name + "-" + getSeqid() + "-" + tableNameStr;
147   }
148 }