-
Notifications
You must be signed in to change notification settings - Fork 2.3k
/
RecoveryProtocol.java
200 lines (172 loc) · 7.6 KB
/
RecoveryProtocol.java
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
/*
* Copyright (c) 2002-2016 "Neo Technology,"
* Network Engine for Objects in Lund AB [http://neotechnology.com]
*
* This file is part of Neo4j.
*
* Neo4j is free software: you can redistribute it and/or modify
* it under the terms of the GNU Affero General Public License as
* published by the Free Software Foundation, either version 3 of the
* License, or (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU Affero General Public License for more details.
*
* You should have received a copy of the GNU Affero General Public License
* along with this program. If not, see <http://www.gnu.org/licenses/>.
*/
package org.neo4j.coreedge.raft.log.segmented;
import java.io.File;
import java.io.IOException;
import java.util.ArrayList;
import java.util.List;
import java.util.Map;
import java.util.SortedMap;
import org.neo4j.coreedge.raft.log.EntryRecord;
import org.neo4j.coreedge.raft.replication.ReplicatedContent;
import org.neo4j.coreedge.raft.state.ChannelMarshal;
import org.neo4j.coreedge.raft.state.EndOfStreamException;
import org.neo4j.cursor.IOCursor;
import org.neo4j.io.fs.FileSystemAbstraction;
import org.neo4j.io.fs.StoreChannel;
import org.neo4j.kernel.impl.transaction.log.PhysicalFlushableChannel;
import org.neo4j.kernel.impl.transaction.log.ReadAheadChannel;
import org.neo4j.logging.Log;
import org.neo4j.logging.LogProvider;
import static java.util.Collections.emptyList;
/**
* Recovers all the state required for operating the RAFT log and does some simple
* verifications; e.g. checking for gaps, verifying headers.
*/
class RecoveryProtocol
{
private static final SegmentHeader.Marshal headerMarshal = new SegmentHeader.Marshal();
private final FileSystemAbstraction fileSystem;
private final FileNames fileNames;
private final ChannelMarshal<ReplicatedContent> contentMarshal;
private final LogProvider logProvider;
private final Log log;
private ReaderPool readerPool;
RecoveryProtocol( FileSystemAbstraction fileSystem, FileNames fileNames, ReaderPool readerPool,
ChannelMarshal<ReplicatedContent> contentMarshal, LogProvider logProvider )
{
this.fileSystem = fileSystem;
this.fileNames = fileNames;
this.readerPool = readerPool;
this.contentMarshal = contentMarshal;
this.logProvider = logProvider;
this.log = logProvider.getLog( getClass() );
}
State run() throws IOException, DamagedLogStorageException, DisposedException
{
State state = new State();
SortedMap<Long,File> files = fileNames.getAllFiles( fileSystem, log );
if ( files.entrySet().isEmpty() )
{
state.segments = new Segments( fileSystem, fileNames, readerPool, emptyList(), contentMarshal, logProvider, -1 );
state.segments.rotate( -1, -1, -1 );
state.terms = new Terms( -1, -1 );
return state;
}
List<SegmentFile> segmentFiles = new ArrayList<>();
SegmentFile segment = null;
long firstVersion = files.firstKey();
long expectedVersion = firstVersion;
boolean mustRecoverLastHeader = false;
for ( Map.Entry<Long,File> entry : files.entrySet() )
{
long fileNameVersion = entry.getKey();
File file = entry.getValue();
SegmentHeader header;
checkVersionSequence( fileNameVersion, expectedVersion );
try
{
header = loadHeader( fileSystem, file );
checkVersionMatches( header.version(), fileNameVersion );
}
catch ( EndOfStreamException e )
{
if ( files.lastKey() != fileNameVersion )
{
throw new DamagedLogStorageException( e, "Intermediate file with incomplete or no header found: %s", file );
}
else if ( files.size() == 1 )
{
throw new DamagedLogStorageException( e, "Single file with incomplete or no header found: %s", file );
}
/* Last file header must be recovered by scanning next-to-last file and writing a new header based on that. */
mustRecoverLastHeader = true;
break;
}
segment = new SegmentFile( fileSystem, file, readerPool, fileNameVersion, contentMarshal, logProvider, header );
segmentFiles.add( segment );
if ( fileNameVersion == firstVersion )
{
state.prevIndex = segment.header().prevIndex();
state.prevTerm = segment.header().prevTerm();
}
expectedVersion++;
}
assert segment != null;
state.segments = new Segments( fileSystem, fileNames, readerPool, segmentFiles, contentMarshal, logProvider, segment.header().version() );
state.appendIndex = segment.header().prevIndex();
state.terms = new Terms( segment.header().prevIndex(), segment.header().prevTerm() );
try ( IOCursor<EntryRecord> cursor = segment.getCursor( segment.header().prevIndex() + 1 ) )
{
while ( cursor.next() )
{
EntryRecord entry = cursor.get();
state.appendIndex = entry.logIndex();
state.terms.append( state.appendIndex, entry.logEntry().term() );
}
}
if ( mustRecoverLastHeader )
{
SegmentHeader header = new SegmentHeader( state.appendIndex, expectedVersion, state.appendIndex, state.terms.latest() );
log.warn( "Recovering last file based on next-to-last file. " + header );
File file = fileNames.getForVersion( expectedVersion );
writeHeader( fileSystem, file, header );
segment = new SegmentFile( fileSystem, file, readerPool, expectedVersion, contentMarshal, logProvider, header );
segmentFiles.add( segment );
}
return state;
}
private static SegmentHeader loadHeader(
FileSystemAbstraction fileSystem,
File file ) throws IOException, EndOfStreamException
{
try ( StoreChannel channel = fileSystem.open( file, "r" ) )
{
return headerMarshal.unmarshal( new ReadAheadChannel<>( channel, SegmentHeader.SIZE ) );
}
}
private static void writeHeader(
FileSystemAbstraction fileSystem,
File file,
SegmentHeader header ) throws IOException
{
try ( StoreChannel channel = fileSystem.open( file, "rw" ) )
{
channel.position( 0 );
PhysicalFlushableChannel writer = new PhysicalFlushableChannel( channel, SegmentHeader.SIZE );
headerMarshal.marshal( header, writer );
writer.prepareForFlush().flush();
}
}
private static void checkVersionSequence( long fileNameVersion, long expectedVersion ) throws DamagedLogStorageException
{
if ( fileNameVersion != expectedVersion )
{
throw new DamagedLogStorageException( "File versions not strictly monotonic. Expected: %d but found: %d", expectedVersion, fileNameVersion );
}
}
private static void checkVersionMatches( long headerVersion, long fileNameVersion ) throws DamagedLogStorageException
{
if ( headerVersion != fileNameVersion )
{
throw new DamagedLogStorageException( "File version does not match header version. Expected: %d but found: %d", headerVersion, fileNameVersion );
}
}
}