View Javadoc

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.client.TableState;
41  import org.apache.hadoop.hbase.executor.EventType;
42  import org.apache.hadoop.hbase.master.HMaster;
43  import org.apache.hadoop.hbase.master.MasterCoprocessorHost;
44  import org.apache.hadoop.hbase.master.MasterFileSystem;
45  import org.apache.hadoop.hbase.master.MasterServices;
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(), TableState.State.ENABLED)
69          && this.htd.getRegionReplication() != getTableDescriptor()
70          .getHTableDescriptor().getRegionReplication()) {
71        throw new IOException("REGION_REPLICATION change is not supported for enabled tables");
72      }
73    }
74  
75    @Override
76    protected void handleTableOperation(List<HRegionInfo> hris)
77    throws IOException {
78      MasterCoprocessorHost cpHost = ((HMaster) this.server).getMasterCoprocessorHost();
79      if (cpHost != null) {
80        cpHost.preModifyTableHandler(this.tableName, this.htd);
81      }
82      // Update descriptor
83      HTableDescriptor oldDescriptor =
84          this.masterServices.getTableDescriptors().get(this.tableName);
85      this.masterServices.getTableDescriptors().add(htd);
86      deleteFamilyFromFS(hris, oldDescriptor.getFamiliesKeys());
87      removeReplicaColumnsIfNeeded(
88          this.htd.getRegionReplication(),
89          oldDescriptor.getRegionReplication(),
90          this.htd.getTableName());
91      if (cpHost != null) {
92        cpHost.postModifyTableHandler(this.tableName, this.htd);
93      }
94    }
95  
96    private void removeReplicaColumnsIfNeeded(int newReplicaCount, int oldReplicaCount,
97        TableName table) throws IOException {
98      if (newReplicaCount >= oldReplicaCount) return;
99      Set<byte[]> tableRows = new HashSet<byte[]>();
100     Scan scan = MetaTableAccessor.getScanForTableName(table);
101     scan.addColumn(HConstants.CATALOG_FAMILY, HConstants.REGIONINFO_QUALIFIER);
102     Connection connection = this.masterServices.getConnection();
103     try (Table metaTable = connection.getTable(TableName.META_TABLE_NAME)) {
104       ResultScanner resScanner = metaTable.getScanner(scan);
105       for (Result result : resScanner) {
106         tableRows.add(result.getRow());
107       }
108       MetaTableAccessor.removeRegionReplicasFromMeta(tableRows, newReplicaCount,
109         oldReplicaCount - newReplicaCount, masterServices.getConnection());
110     }
111   }
112 
113   /**
114    * Removes from hdfs the families that are not longer present in the new table descriptor.
115    */
116   private void deleteFamilyFromFS(final List<HRegionInfo> hris, final Set<byte[]> oldFamilies) {
117     try {
118       Set<byte[]> newFamilies = this.htd.getFamiliesKeys();
119       MasterFileSystem mfs = this.masterServices.getMasterFileSystem();
120       for (byte[] familyName: oldFamilies) {
121         if (!newFamilies.contains(familyName)) {
122           LOG.debug("Removing family=" + Bytes.toString(familyName) +
123                     " from table=" + this.tableName);
124           for (HRegionInfo hri: hris) {
125             // Delete the family directory in FS for all the regions one by one
126             mfs.deleteFamilyFromFS(hri, familyName);
127           }
128         }
129       }
130     } catch (IOException e) {
131       LOG.warn("Unable to remove on-disk directories for the removed families", e);
132     }
133   }
134 
135   @Override
136   public String toString() {
137     String name = "UnknownServerName";
138     if(server != null && server.getServerName() != null) {
139       name = server.getServerName().toString();
140     }
141     return getClass().getSimpleName() + "-" + name + "-" + getSeqid() + "-" +
142       tableName;
143   }
144 }