/**
*
* 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.master.handler;
import java.io.IOException;
import java.io.InterruptedIOException;
import java.util.List;
import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;
import org.apache.hadoop.classification.InterfaceAudience;
import org.apache.hadoop.conf.Configuration;
import org.apache.hadoop.fs.FileSystem;
import org.apache.hadoop.fs.Path;
import org.apache.hadoop.hbase.HRegionInfo;
import org.apache.hadoop.hbase.HTableDescriptor;
import org.apache.hadoop.hbase.exceptions.NotAllMetaRegionsOnlineException;
import org.apache.hadoop.hbase.Server;
import org.apache.hadoop.hbase.exceptions.TableExistsException;
import org.apache.hadoop.hbase.catalog.CatalogTracker;
import org.apache.hadoop.hbase.catalog.MetaEditor;
import org.apache.hadoop.hbase.catalog.MetaReader;
import org.apache.hadoop.hbase.executor.EventHandler;
import org.apache.hadoop.hbase.executor.EventType;
import org.apache.hadoop.hbase.master.AssignmentManager;
import org.apache.hadoop.hbase.master.HMaster;
import org.apache.hadoop.hbase.master.MasterCoprocessorHost;
import org.apache.hadoop.hbase.master.MasterFileSystem;
import org.apache.hadoop.hbase.master.MasterServices;
import org.apache.hadoop.hbase.master.TableLockManager;
import org.apache.hadoop.hbase.master.TableLockManager.TableLock;
import org.apache.hadoop.hbase.util.FSTableDescriptors;
import org.apache.hadoop.hbase.util.ModifyRegionUtils;
import org.apache.zookeeper.KeeperException;
/**
* Handler to create a table.
*/
@InterfaceAudience.Private
public class CreateTableHandler extends EventHandler {
private static final Log LOG = LogFactory.getLog(CreateTableHandler.class);
protected final MasterFileSystem fileSystemManager;
protected final HTableDescriptor hTableDescriptor;
protected final Configuration conf;
private final AssignmentManager assignmentManager;
private final CatalogTracker catalogTracker;
private final TableLockManager tableLockManager;
private final HRegionInfo [] newRegions;
private final TableLock tableLock;
public CreateTableHandler(Server server, MasterFileSystem fileSystemManager,
HTableDescriptor hTableDescriptor, Configuration conf, HRegionInfo [] newRegions,
MasterServices masterServices) {
super(server, EventType.C_M_CREATE_TABLE);
this.fileSystemManager = fileSystemManager;
this.hTableDescriptor = hTableDescriptor;
this.conf = conf;
this.newRegions = newRegions;
this.catalogTracker = masterServices.getCatalogTracker();
this.assignmentManager = masterServices.getAssignmentManager();
this.tableLockManager = masterServices.getTableLockManager();
this.tableLock = this.tableLockManager.writeLock(this.hTableDescriptor.getName()
, EventType.C_M_CREATE_TABLE.toString());
}
public CreateTableHandler prepare()
throws NotAllMetaRegionsOnlineException, TableExistsException, IOException {
int timeout = conf.getInt("hbase.client.catalog.timeout", 10000);
// Need META availability to create a table
try {
if(catalogTracker.waitForMeta(timeout) == null) {
throw new NotAllMetaRegionsOnlineException();
}
} catch (InterruptedException e) {
LOG.warn("Interrupted waiting for meta availability", e);
InterruptedIOException ie = new InterruptedIOException(e.getMessage());
ie.initCause(e);
throw ie;
}
//acquire the table write lock, blocking. Make sure that it is released.
this.tableLock.acquire();
boolean success = false;
try {
String tableName = this.hTableDescriptor.getNameAsString();
if (MetaReader.tableExists(catalogTracker, tableName)) {
throw new TableExistsException(tableName);
}
// If we have multiple client threads trying to create the table at the
// same time, given the async nature of the operation, the table
// could be in a state where .META. table hasn't been updated yet in
// the process() function.
// Use enabling state to tell if there is already a request for the same
// table in progress. This will introduce a new zookeeper call. Given
// createTable isn't a frequent operation, that should be ok.
//TODO: now that we have table locks, re-evaluate above
try {
if (!this.assignmentManager.getZKTable().checkAndSetEnablingTable(tableName)) {
throw new TableExistsException(tableName);
}
} catch (KeeperException e) {
throw new IOException("Unable to ensure that the table will be" +
" enabling because of a ZooKeeper issue", e);
}
success = true;
} finally {
if (!success) {
releaseTableLock();
}
}
return this;
}
@Override
public String toString() {
String name = "UnknownServerName";
if(server != null && server.getServerName() != null) {
name = server.getServerName().toString();
}
return getClass().getSimpleName() + "-" + name + "-" + getSeqid() + "-" +
this.hTableDescriptor.getNameAsString();
}
@Override
public void process() {
String tableName = this.hTableDescriptor.getNameAsString();
LOG.info("Attempting to create the table " + tableName);
try {
MasterCoprocessorHost cpHost = ((HMaster) this.server).getCoprocessorHost();
if (cpHost != null) {
cpHost.preCreateTableHandler(this.hTableDescriptor, this.newRegions);
}
handleCreateTable(tableName);
completed(null);
if (cpHost != null) {
cpHost.postCreateTableHandler(this.hTableDescriptor, this.newRegions);
}
} catch (Throwable e) {
LOG.error("Error trying to create the table " + tableName, e);
completed(e);
}
}
/**
* Called after that process() is completed.
* @param exception null if process() is successful or not null if something has failed.
*/
protected void completed(final Throwable exception) {
releaseTableLock();
if (exception != null) {
// Try deleting the enabling node in case of error
// If this does not happen then if the client tries to create the table
// again with the same Active master
// It will block the creation saying TableAlreadyExists.
this.assignmentManager.getZKTable().removeEnablingTable(
this.hTableDescriptor.getNameAsString());
}
}
/**
* Responsible of table creation (on-disk and META) and assignment.
* - Create the table directory and descriptor (temp folder)
* - Create the on-disk regions (temp folder)
* [If something fails here: we've just some trash in temp]
* - Move the table from temp to the root directory
* [If something fails here: we've the table in place but some of the rows required
* present in META. (hbck needed)]
* - Add regions to META
* [If something fails here: we don't have regions assigned: table disabled]
* - Assign regions to Region Servers
* [If something fails here: we still have the table in disabled state]
* - Update ZooKeeper with the enabled state
*/
private void handleCreateTable(String tableName) throws IOException, KeeperException {
Path tempdir = fileSystemManager.getTempDir();
FileSystem fs = fileSystemManager.getFileSystem();
// 1. Create Table Descriptor
FSTableDescriptors.createTableDescriptor(fs, tempdir, this.hTableDescriptor);
Path tempTableDir = new Path(tempdir, tableName);
Path tableDir = new Path(fileSystemManager.getRootDir(), tableName);
// 2. Create Regions
List<HRegionInfo> regionInfos = handleCreateHdfsRegions(tempdir, tableName);
// 3. Move Table temp directory to the hbase root location
if (!fs.rename(tempTableDir, tableDir)) {
throw new IOException("Unable to move table from temp=" + tempTableDir +
" to hbase root=" + tableDir);
}
if (regionInfos != null && regionInfos.size() > 0) {
// 4. Add regions to META
MetaEditor.addRegionsToMeta(this.catalogTracker, regionInfos);
// 5. Trigger immediate assignment of the regions in round-robin fashion
try {
assignmentManager.getRegionStates().createRegionStates(regionInfos);
assignmentManager.assign(regionInfos);
} catch (InterruptedException e) {
LOG.error("Caught " + e + " during round-robin assignment");
InterruptedIOException ie = new InterruptedIOException(e.getMessage());
ie.initCause(e);
throw ie;
}
}
// 6. Set table enabled flag up in zk.
try {
assignmentManager.getZKTable().setEnabledTable(tableName);
} catch (KeeperException e) {
throw new IOException("Unable to ensure that " + tableName + " will be" +
" enabled because of a ZooKeeper issue", e);
}
}
private void releaseTableLock() {
if (this.tableLock != null) {
try {
this.tableLock.release();
} catch (IOException ex) {
LOG.warn("Could not release the table lock", ex);
}
}
}
/**
* Create the on-disk structure for the table, and returns the regions info.
* @param tableRootDir directory where the table is being created
* @param tableName name of the table under construction
* @return the list of regions created
*/
protected List<HRegionInfo> handleCreateHdfsRegions(final Path tableRootDir,
final String tableName)
throws IOException {
return ModifyRegionUtils.createRegions(conf, tableRootDir,
hTableDescriptor, newRegions, null);
}
}