| /* |
| * 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.directory.mavibot.btree; |
| |
| |
| import java.io.File; |
| import java.io.FileInputStream; |
| import java.io.FileOutputStream; |
| import java.io.InputStream; |
| import java.io.ObjectInputStream; |
| import java.io.ObjectOutputStream; |
| import java.io.OutputStream; |
| import java.util.ArrayList; |
| import java.util.Collections; |
| import java.util.Iterator; |
| import java.util.List; |
| import java.util.Map; |
| import java.util.Set; |
| import java.util.TreeSet; |
| import java.util.concurrent.ConcurrentHashMap; |
| |
| import org.slf4j.Logger; |
| import org.slf4j.LoggerFactory; |
| |
| |
| /** |
| * A class used for reclaiming the copied pages. |
| * |
| * @author <a href="mailto:dev@directory.apache.org">Apache Directory Project</a> |
| */ |
| public class SpaceReclaimer |
| { |
| /** the record manager */ |
| private RecordManager rm; |
| |
| private static String COPIED_PAGE_MAP_DATA_FILE = "cpm.db"; |
| |
| /** The LoggerFactory used by this class */ |
| protected static final Logger LOG = LoggerFactory.getLogger( SpaceReclaimer.class ); |
| |
| /** |
| * Creates a new instance of SpaceReclaimer. |
| * |
| * @param rm the record manager |
| */ |
| public SpaceReclaimer( RecordManager rm ) |
| { |
| this.rm = rm; |
| } |
| |
| |
| /** |
| * stores the copied page map, if not empty, in a file under the given directory |
| * |
| * @param dir the directory where mavibot database file is present |
| */ |
| /* no qualifier */ void storeCopiedPageMap( File dir ) |
| { |
| if ( rm.copiedPageMap.isEmpty() ) |
| { |
| LOG.debug( "Copied page map is empty, nothing to store on disk." ); |
| return; |
| } |
| |
| File file = new File( dir, COPIED_PAGE_MAP_DATA_FILE ); |
| |
| try |
| { |
| LOG.debug( "Storing {} RevisionName of Copied page map", rm.copiedPageMap.size() ); |
| |
| OutputStream fileOut = new FileOutputStream( file ); |
| |
| ObjectOutputStream objOut = new ObjectOutputStream( fileOut ); |
| |
| objOut.writeObject( rm.copiedPageMap ); |
| |
| objOut.close(); |
| |
| LOG.debug( "Successfully stored copied page map in {}", file.getAbsolutePath() ); |
| } |
| catch( Exception e ) |
| { |
| LOG.warn( "Failed to store the copied page map in {}", file.getAbsolutePath() ); |
| LOG.warn( "", e ); |
| } |
| } |
| |
| |
| /** |
| * reads the copied page map from the file named {@link #COPIED_PAGE_MAP_DATA_FILE} if it |
| * is present under the given directory |
| * |
| * @param dir the directory where mavibot database file is present |
| * |
| * @return |
| */ |
| /* no qualifier */ ConcurrentHashMap<RevisionName, long[]> readCopiedPageMap( File dir ) |
| { |
| |
| ConcurrentHashMap<RevisionName, long[]> map = new ConcurrentHashMap<RevisionName, long[]>(); |
| |
| File file = new File( dir, COPIED_PAGE_MAP_DATA_FILE ); |
| |
| if ( !file.exists() ) |
| { |
| LOG.debug( "Copied page map store {} doesn't exist, returning empty map", file.getAbsolutePath() ); |
| return map; |
| } |
| |
| try |
| { |
| LOG.debug( "Reading Copied page map data stored in {}", file.getAbsolutePath() ); |
| |
| InputStream fileIn = new FileInputStream( file ); |
| |
| ObjectInputStream objIn = new ObjectInputStream( fileIn ); |
| |
| map = ( ConcurrentHashMap<RevisionName, long[]> ) objIn.readObject(); |
| |
| objIn.close(); |
| |
| LOG.debug( "Successfully read copied page map containing {} RevisionNames", map.size() ); |
| } |
| catch( Exception e ) |
| { |
| LOG.warn( "Failed to read the copied page map from {}", file.getAbsolutePath() ); |
| LOG.warn( "", e ); |
| } |
| finally |
| { |
| boolean deleted = file.delete(); |
| |
| // this is dangerous, cause during a subsequent restart the pages |
| // will be freed again, but this time they might have been in use |
| if( !deleted ) |
| { |
| String warn = "Failed to delete the copied page map store " + file.getAbsolutePath() + |
| " Make sure the approapriate permissions are given to delete this file by mavibot process." ; |
| LOG.warn( warn ); |
| |
| throw new RuntimeException( warn ); |
| } |
| } |
| |
| return map; |
| } |
| |
| |
| /** |
| * relcaims the copied pages |
| */ |
| /* no qualifier */ void reclaim() |
| { |
| //System.out.println( "reclaiming pages" ); |
| try |
| { |
| Set<String> managed = rm.getManagedTrees(); |
| |
| for ( String name : managed ) |
| { |
| PersistedBTree tree = ( PersistedBTree ) rm.getManagedTree( name ); |
| |
| Set<Long> inUseRevisions = new TreeSet<Long>(); |
| |
| // the tree might have been removed |
| if ( tree != null ) |
| { |
| Iterator<ReadTransaction> txnItr = tree.getReadTransactions().iterator(); |
| while ( txnItr.hasNext() ) |
| { |
| inUseRevisions.add( txnItr.next().getRevision() ); |
| } |
| } |
| |
| List<RevisionOffset> copiedRevisions = getRevisions( name ); |
| |
| for ( RevisionOffset ro : copiedRevisions ) |
| { |
| long rv = ro.getRevision(); |
| if ( inUseRevisions.contains( rv ) ) |
| { |
| //System.out.println( "Revision " + rv + " of BTree " + name + " is in use, not reclaiming pages" ); |
| break; |
| } |
| |
| long[] offsets = ro.getOffsets(); |
| |
| //System.out.println( "Reclaiming " + Arrays.toString( offsets ) + "( " + offsets.length + " ) pages of the revision " + rv + " of BTree " + name ); |
| |
| rm.free( offsets ); |
| |
| RevisionName key = new RevisionName( rv, name ); |
| rm.copiedPageMap.remove( key ); |
| } |
| } |
| } |
| catch ( Exception e ) |
| { |
| e.printStackTrace(); |
| } |
| } |
| |
| |
| /** |
| * gets a list of all the copied pages of a given B-Tree. |
| * |
| * @param name the name of the B-Tree |
| * @return list of RevisionOffset |
| * @throws Exception |
| */ |
| private List<RevisionOffset> getRevisions( String name ) throws Exception |
| { |
| long nbElems = rm.copiedPageMap.size(); |
| //System.out.println( "Total number of entries in CPB " + nbElems ); |
| |
| if ( nbElems == 0 ) |
| { |
| return Collections.EMPTY_LIST; |
| } |
| |
| Iterator<Map.Entry<RevisionName, long[]>> cursor = rm.copiedPageMap.entrySet().iterator(); |
| |
| List<RevisionOffset> lst = new ArrayList<RevisionOffset>(); |
| |
| while ( cursor.hasNext() ) |
| { |
| Map.Entry<RevisionName, long[]> t = cursor.next(); |
| RevisionName rn = t.getKey(); |
| if ( name.equals( rn.getName() ) ) |
| { |
| //System.out.println( t.getValue() ); |
| lst.add( new RevisionOffset( rn.getRevision(), t.getValue() ) ); |
| } |
| } |
| |
| return lst; |
| } |
| } |