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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.TableName;
30  import org.apache.hadoop.hbase.HRegionInfo;
31  import org.apache.hadoop.hbase.Server;
32  import org.apache.hadoop.hbase.backup.HFileArchiver;
33  import org.apache.hadoop.hbase.catalog.MetaEditor;
34  import org.apache.hadoop.hbase.executor.EventType;
35  import org.apache.hadoop.hbase.master.AssignmentManager;
36  import org.apache.hadoop.hbase.master.HMaster;
37  import org.apache.hadoop.hbase.master.MasterCoprocessorHost;
38  import org.apache.hadoop.hbase.master.MasterFileSystem;
39  import org.apache.hadoop.hbase.master.MasterServices;
40  import org.apache.hadoop.hbase.master.RegionStates;
41  import org.apache.hadoop.hbase.master.RegionState.State;
42  import org.apache.hadoop.hbase.util.Bytes;
43  import org.apache.hadoop.hbase.util.Threads;
44  import org.apache.zookeeper.KeeperException;
45  
46  @InterfaceAudience.Private
47  public class DeleteTableHandler extends TableEventHandler {
48    private static final Log LOG = LogFactory.getLog(DeleteTableHandler.class);
49  
50    public DeleteTableHandler(TableName tableName, Server server,
51        final MasterServices masterServices) {
52      super(EventType.C_M_DELETE_TABLE, tableName, server, masterServices);
53    }
54  
55    @Override
56    protected void prepareWithTableLock() throws IOException {
57      // The next call fails if no such table.
58      getTableDescriptor();
59    }
60  
61    @Override
62    protected void handleTableOperation(List<HRegionInfo> regions)
63    throws IOException, KeeperException {
64      MasterCoprocessorHost cpHost = ((HMaster) this.server)
65          .getCoprocessorHost();
66      if (cpHost != null) {
67        cpHost.preDeleteTableHandler(this.tableName);
68      }
69  
70      // 1. Wait because of region in transition
71      AssignmentManager am = this.masterServices.getAssignmentManager();
72      RegionStates states = am.getRegionStates();
73      long waitTime = server.getConfiguration().
74        getLong("hbase.master.wait.on.region", 5 * 60 * 1000);
75      for (HRegionInfo region : regions) {
76        long done = System.currentTimeMillis() + waitTime;
77        while (System.currentTimeMillis() < done) {
78          if (states.isRegionInState(region, State.FAILED_OPEN)) {
79            am.regionOffline(region);
80          }
81          if (!states.isRegionInTransition(region)) break;
82          Threads.sleep(waitingTimeForEvents);
83          LOG.debug("Waiting on region to clear regions in transition; "
84            + am.getRegionStates().getRegionTransitionState(region));
85        }
86        if (states.isRegionInTransition(region)) {
87          throw new IOException("Waited hbase.master.wait.on.region (" +
88            waitTime + "ms) for region to leave region " +
89            region.getRegionNameAsString() + " in transitions");
90        }
91      }
92  
93      // 2. Remove regions from META
94      LOG.debug("Deleting regions from META");
95      MetaEditor.deleteRegions(this.server.getCatalogTracker(), regions);
96  
97      // 3. Move the table in /hbase/.tmp
98      MasterFileSystem mfs = this.masterServices.getMasterFileSystem();
99      Path tempTableDir = mfs.moveTableToTemp(tableName);
100 
101     try {
102       // 4. Delete regions from FS (temp directory)
103       FileSystem fs = mfs.getFileSystem();
104       for (HRegionInfo hri: regions) {
105         LOG.debug("Archiving region " + hri.getRegionNameAsString() + " from FS");
106         HFileArchiver.archiveRegion(fs, mfs.getRootDir(),
107             tempTableDir, new Path(tempTableDir, hri.getEncodedName()));
108       }
109 
110       // 5. Delete table from FS (temp directory)
111       if (!fs.delete(tempTableDir, true)) {
112         LOG.error("Couldn't delete " + tempTableDir);
113       }
114 
115       LOG.debug("Table '" + tableName + "' archived!");
116     } finally {
117       // 6. Update table descriptor cache
118       LOG.debug("Removing '" + tableName + "' descriptor.");
119       this.masterServices.getTableDescriptors().remove(tableName);
120 
121       // 7. If entry for this table in zk, and up in AssignmentManager, remove it.
122       LOG.debug("Marking '" + tableName + "' as deleted.");
123       am.getZKTable().setDeletedTable(tableName);
124     }
125 
126     if (cpHost != null) {
127       cpHost.postDeleteTableHandler(this.tableName);
128     }
129   }
130 
131   @Override
132   protected void releaseTableLock() {
133     super.releaseTableLock();
134     try {
135       masterServices.getTableLockManager().tableDeleted(tableName);
136     } catch (IOException ex) {
137       LOG.warn("Received exception from TableLockManager.tableDeleted:", ex); //not critical
138     }
139   }
140 
141   @Override
142   public String toString() {
143     String name = "UnknownServerName";
144     if(server != null && server.getServerName() != null) {
145       name = server.getServerName().toString();
146     }
147     return getClass().getSimpleName() + "-" + name + "-" + getSeqid() + "-" + tableName;
148   }
149 }