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
|
/*
* 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.ozone.container.common.utils;
import com.google.common.base.Preconditions;
import org.apache.commons.collections.MapIterator;
import org.apache.commons.collections.map.LRUMap;
import org.apache.hadoop.conf.Configuration;
import org.apache.hadoop.ozone.OzoneConfigKeys;
import org.apache.hadoop.utils.MetadataStore;
import org.apache.hadoop.utils.MetadataStoreBuilder;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import java.io.File;
import java.io.IOException;
import java.util.concurrent.locks.Lock;
import java.util.concurrent.locks.ReentrantLock;
/**
* container cache is a LRUMap that maintains the DB handles.
*/
public final class ContainerCache extends LRUMap {
private static final Logger LOG =
LoggerFactory.getLogger(ContainerCache.class);
private final Lock lock = new ReentrantLock();
private static ContainerCache cache;
private static final float LOAD_FACTOR = 0.75f;
/**
* Constructs a cache that holds DBHandle references.
*/
private ContainerCache(int maxSize, float loadFactor, boolean
scanUntilRemovable) {
super(maxSize, loadFactor, scanUntilRemovable);
}
/**
* Return a singleton instance of {@link ContainerCache}
* that holds the DB handlers.
*
* @param conf - Configuration.
* @return A instance of {@link ContainerCache}.
*/
public synchronized static ContainerCache getInstance(Configuration conf) {
if (cache == null) {
int cacheSize = conf.getInt(OzoneConfigKeys.OZONE_CONTAINER_CACHE_SIZE,
OzoneConfigKeys.OZONE_CONTAINER_CACHE_DEFAULT);
cache = new ContainerCache(cacheSize, LOAD_FACTOR, true);
}
return cache;
}
/**
* Closes a db instance.
*
* @param container - name of the container to be closed.
* @param db - db instance to close.
*/
private void closeDB(String container, MetadataStore db) {
if (db != null) {
try {
db.close();
} catch (IOException e) {
LOG.error("Error closing DB. Container: " + container, e);
}
}
}
/**
* Closes all the db instances and resets the cache.
*/
public void shutdownCache() {
lock.lock();
try {
// iterate the cache and close each db
MapIterator iterator = cache.mapIterator();
while (iterator.hasNext()) {
iterator.next();
MetadataStore db = (MetadataStore) iterator.getValue();
closeDB(iterator.getKey().toString(), db);
}
// reset the cache
cache.clear();
} finally {
lock.unlock();
}
}
/**
* {@inheritDoc}
*/
@Override
protected boolean removeLRU(LinkEntry entry) {
lock.lock();
try {
MetadataStore db = (MetadataStore) entry.getValue();
closeDB(entry.getKey().toString(), db);
} finally {
lock.unlock();
}
return true;
}
/**
* Returns a DB handle if available, create the handler otherwise.
*
* @param containerName - Name of the container.
* @return MetadataStore.
*/
public MetadataStore getDB(String containerName, String containerDBPath)
throws IOException {
Preconditions.checkNotNull(containerName);
Preconditions.checkState(!containerName.isEmpty());
lock.lock();
try {
MetadataStore db = (MetadataStore) this.get(containerName);
if (db == null) {
db = MetadataStoreBuilder.newBuilder()
.setDbFile(new File(containerDBPath))
.setCreateIfMissing(false)
.build();
this.put(containerName, db);
}
return db;
} catch (Exception e) {
LOG.error("Error opening DB. Container:{} ContainerPath:{}",
containerName, containerDBPath, e);
throw e;
} finally {
lock.unlock();
}
}
/**
* Remove a DB handler from cache.
*
* @param containerName - Name of the container.
*/
public void removeDB(String containerName) {
Preconditions.checkNotNull(containerName);
Preconditions.checkState(!containerName.isEmpty());
lock.lock();
try {
MetadataStore db = (MetadataStore)this.get(containerName);
closeDB(containerName, db);
this.remove(containerName);
} finally {
lock.unlock();
}
}
}
|
