Java tutorial
/** * * 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.InterruptedIOException; import java.io.IOException; 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.fs.FileSystem; import org.apache.hadoop.fs.Path; import org.apache.hadoop.hbase.CoordinatedStateException; import org.apache.hadoop.hbase.TableName; import org.apache.hadoop.hbase.HRegionInfo; import org.apache.hadoop.hbase.HTableDescriptor; import org.apache.hadoop.hbase.Server; import org.apache.hadoop.hbase.backup.HFileArchiver; import org.apache.hadoop.hbase.catalog.MetaEditor; import org.apache.hadoop.hbase.executor.EventType; import org.apache.hadoop.hbase.regionserver.HRegion; 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.RegionStates; import org.apache.hadoop.hbase.master.RegionState.State; @InterfaceAudience.Private public class DeleteTableHandler extends TableEventHandler { private static final Log LOG = LogFactory.getLog(DeleteTableHandler.class); protected HTableDescriptor hTableDescriptor = null; public DeleteTableHandler(TableName tableName, Server server, final MasterServices masterServices) { super(EventType.C_M_DELETE_TABLE, tableName, server, masterServices); } @Override protected void prepareWithTableLock() throws IOException { // The next call fails if no such table. hTableDescriptor = getTableDescriptor(); } protected void waitRegionInTransition(final List<HRegionInfo> regions) throws IOException, CoordinatedStateException { AssignmentManager am = this.masterServices.getAssignmentManager(); RegionStates states = am.getRegionStates(); long waitTime = server.getConfiguration().getLong("hbase.master.wait.on.region", 5 * 60 * 1000); for (HRegionInfo region : regions) { long done = System.currentTimeMillis() + waitTime; while (System.currentTimeMillis() < done) { if (states.isRegionInState(region, State.FAILED_OPEN)) { am.regionOffline(region); } if (!states.isRegionInTransition(region)) break; try { Thread.sleep(waitingTimeForEvents); } catch (InterruptedException e) { LOG.warn("Interrupted while sleeping"); throw (InterruptedIOException) new InterruptedIOException().initCause(e); } LOG.debug("Waiting on region to clear regions in transition; " + am.getRegionStates().getRegionTransitionState(region)); } if (states.isRegionInTransition(region)) { throw new IOException("Waited hbase.master.wait.on.region (" + waitTime + "ms) for region to leave region " + region.getRegionNameAsString() + " in transitions"); } } } @Override protected void handleTableOperation(List<HRegionInfo> regions) throws IOException, CoordinatedStateException { MasterCoprocessorHost cpHost = ((HMaster) this.server).getMasterCoprocessorHost(); if (cpHost != null) { cpHost.preDeleteTableHandler(this.tableName); } // 1. Wait because of region in transition waitRegionInTransition(regions); try { // 2. Remove table from hbase:meta and HDFS removeTableData(regions); } finally { // 3. Update table descriptor cache LOG.debug("Removing '" + tableName + "' descriptor."); this.masterServices.getTableDescriptors().remove(tableName); AssignmentManager am = this.masterServices.getAssignmentManager(); // 4. Clean up regions of the table in RegionStates. LOG.debug("Removing '" + tableName + "' from region states."); am.getRegionStates().tableDeleted(tableName); // 5. If entry for this table in zk, and up in AssignmentManager, remove it. LOG.debug("Marking '" + tableName + "' as deleted."); am.getTableStateManager().setDeletedTable(tableName); } if (cpHost != null) { cpHost.postDeleteTableHandler(this.tableName); } } /** * Removes the table from hbase:meta and archives the HDFS files. */ protected void removeTableData(final List<HRegionInfo> regions) throws IOException, CoordinatedStateException { // 1. Remove regions from META LOG.debug("Deleting regions from META"); MetaEditor.deleteRegions(this.server.getCatalogTracker(), regions); // ----------------------------------------------------------------------- // NOTE: At this point we still have data on disk, but nothing in hbase:meta // if the rename below fails, hbck will report an inconsistency. // ----------------------------------------------------------------------- // 2. Move the table in /hbase/.tmp MasterFileSystem mfs = this.masterServices.getMasterFileSystem(); Path tempTableDir = mfs.moveTableToTemp(tableName); // 3. Archive regions from FS (temp directory) FileSystem fs = mfs.getFileSystem(); for (HRegionInfo hri : regions) { LOG.debug("Archiving region " + hri.getRegionNameAsString() + " from FS"); HFileArchiver.archiveRegion(fs, mfs.getRootDir(), tempTableDir, HRegion.getRegionDir(tempTableDir, hri.getEncodedName())); } // 4. Delete table directory from FS (temp directory) if (!fs.delete(tempTableDir, true)) { LOG.error("Couldn't delete " + tempTableDir); } LOG.debug("Table '" + tableName + "' archived!"); } @Override protected void releaseTableLock() { super.releaseTableLock(); try { masterServices.getTableLockManager().tableDeleted(tableName); } catch (IOException ex) { LOG.warn("Received exception from TableLockManager.tableDeleted:", ex); //not critical } } @Override public String toString() { String name = "UnknownServerName"; if (server != null && server.getServerName() != null) { name = server.getServerName().toString(); } return getClass().getSimpleName() + "-" + name + "-" + getSeqid() + "-" + tableName; } }