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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.HashSet;
23  import java.util.List;
24  import java.util.Set;
25  
26  import org.apache.commons.logging.Log;
27  import org.apache.commons.logging.LogFactory;
28  import org.apache.hadoop.hbase.HConstants;
29  import org.apache.hadoop.hbase.HRegionInfo;
30  import org.apache.hadoop.hbase.HTableDescriptor;
31  import org.apache.hadoop.hbase.MetaTableAccessor;
32  import org.apache.hadoop.hbase.Server;
33  import org.apache.hadoop.hbase.TableName;
34  import org.apache.hadoop.hbase.classification.InterfaceAudience;
35  import org.apache.hadoop.hbase.client.Connection;
36  import org.apache.hadoop.hbase.client.Result;
37  import org.apache.hadoop.hbase.client.ResultScanner;
38  import org.apache.hadoop.hbase.client.Scan;
39  import org.apache.hadoop.hbase.client.Table;
40  import org.apache.hadoop.hbase.executor.EventType;
41  import org.apache.hadoop.hbase.master.HMaster;
42  import org.apache.hadoop.hbase.master.MasterCoprocessorHost;
43  import org.apache.hadoop.hbase.master.MasterFileSystem;
44  import org.apache.hadoop.hbase.master.MasterServices;
45  import org.apache.hadoop.hbase.protobuf.generated.ZooKeeperProtos;
46  import org.apache.hadoop.hbase.util.Bytes;
47  
48  @InterfaceAudience.Private
49  public class ModifyTableHandler extends TableEventHandler {
50    private static final Log LOG = LogFactory.getLog(ModifyTableHandler.class);
51  
52    private final HTableDescriptor htd;
53  
54    public ModifyTableHandler(final TableName tableName,
55        final HTableDescriptor htd, final Server server,
56        final MasterServices masterServices) {
57      super(EventType.C_M_MODIFY_TABLE, tableName, server, masterServices);
58      // This is the new schema we are going to write out as this modification.
59      this.htd = htd;
60    }
61  
62    @Override
63    protected void prepareWithTableLock() throws IOException {
64      super.prepareWithTableLock();
65      // Check operation is possible on the table in its current state
66      // Also checks whether the table exists
67      if (masterServices.getAssignmentManager().getTableStateManager()
68          .isTableState(this.htd.getTableName(), ZooKeeperProtos.Table.State.ENABLED)
69          && this.htd.getRegionReplication() != getTableDescriptor().getRegionReplication()) {
70        throw new IOException("REGION_REPLICATION change is not supported for enabled tables");
71      }
72    }
73  
74    @Override
75    protected void handleTableOperation(List<HRegionInfo> hris)
76    throws IOException {
77      MasterCoprocessorHost cpHost = ((HMaster) this.server).getMasterCoprocessorHost();
78      if (cpHost != null) {
79        cpHost.preModifyTableHandler(this.tableName, this.htd);
80      }
81      // Update descriptor
82      HTableDescriptor oldHtd = getTableDescriptor();
83      this.masterServices.getTableDescriptors().add(this.htd);
84      deleteFamilyFromFS(hris, oldHtd.getFamiliesKeys());
85      removeReplicaColumnsIfNeeded(this.htd.getRegionReplication(), oldHtd.getRegionReplication(),
86          htd.getTableName());
87      if (cpHost != null) {
88        cpHost.postModifyTableHandler(this.tableName, this.htd);
89      }
90    }
91  
92    private void removeReplicaColumnsIfNeeded(int newReplicaCount, int oldReplicaCount,
93        TableName table) throws IOException {
94      if (newReplicaCount >= oldReplicaCount) return;
95      Set<byte[]> tableRows = new HashSet<byte[]>();
96      Scan scan = MetaTableAccessor.getScanForTableName(table);
97      scan.addColumn(HConstants.CATALOG_FAMILY, HConstants.REGIONINFO_QUALIFIER);
98      Connection connection = this.masterServices.getConnection();
99      try (Table metaTable = connection.getTable(TableName.META_TABLE_NAME)) {
100       ResultScanner resScanner = metaTable.getScanner(scan);
101       for (Result result : resScanner) {
102         tableRows.add(result.getRow());
103       }
104       MetaTableAccessor.removeRegionReplicasFromMeta(tableRows, newReplicaCount,
105         oldReplicaCount - newReplicaCount, masterServices.getConnection());
106     }
107   }
108 
109   /**
110    * Removes from hdfs the families that are not longer present in the new table descriptor.
111    */
112   private void deleteFamilyFromFS(final List<HRegionInfo> hris, final Set<byte[]> oldFamilies) {
113     try {
114       Set<byte[]> newFamilies = this.htd.getFamiliesKeys();
115       MasterFileSystem mfs = this.masterServices.getMasterFileSystem();
116       for (byte[] familyName: oldFamilies) {
117         if (!newFamilies.contains(familyName)) {
118           LOG.debug("Removing family=" + Bytes.toString(familyName) +
119                     " from table=" + this.tableName);
120           for (HRegionInfo hri: hris) {
121             // Delete the family directory in FS for all the regions one by one
122             mfs.deleteFamilyFromFS(hri, familyName);
123           }
124         }
125       }
126     } catch (IOException e) {
127       LOG.warn("Unable to remove on-disk directories for the removed families", e);
128     }
129   }
130 
131   @Override
132   public String toString() {
133     String name = "UnknownServerName";
134     if(server != null && server.getServerName() != null) {
135       name = server.getServerName().toString();
136     }
137     return getClass().getSimpleName() + "-" + name + "-" + getSeqid() + "-" +
138       tableName;
139   }
140 }