1 /*
2 * Licensed to the Apache Software Foundation (ASF) under one
3 * or more contributor license agreements. See the NOTICE file
4 * distributed with this work for additional information
5 * regarding copyright ownership. The ASF licenses this file
6 * to you under the Apache License, Version 2.0 (the
7 * "License"); you may not use this file except in compliance
8 * with the License. You may obtain a copy of the License at
9 *
10 * http://www.apache.org/licenses/LICENSE-2.0
11 *
12 * Unless required by applicable law or agreed to in writing, software
13 * distributed under the License is distributed on an "AS IS" BASIS,
14 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
15 * See the License for the specific language governing permissions and
16 * limitations under the License.
17 */
18
19 package org.apache.hadoop.hbase.codec.prefixtree.decode;
20
21 import java.nio.ByteBuffer;
22 import java.util.Queue;
23 import java.util.concurrent.LinkedBlockingQueue;
24
25 import org.apache.hadoop.hbase.classification.InterfaceAudience;
26
27 /**
28 * Pools PrefixTreeArraySearcher objects. Each Searcher can consist of hundreds or thousands of
29 * objects and 1 is needed for each HFile during a Get operation. With tens of thousands of
30 * Gets/second, reusing these searchers may save a lot of young gen collections.
31 * <p/>
32 * Alternative implementation would be a ByteBufferSearcherPool (not implemented yet).
33 */
34 @InterfaceAudience.Private
35 public class ArraySearcherPool {
36
37 /**
38 * One decoder is needed for each storefile for each Get operation so we may need hundreds at the
39 * same time, however, decoding is a CPU bound activity so should limit this to something in the
40 * realm of maximum reasonable active threads.
41 */
42 private static final Integer MAX_POOL_SIZE = 1000;
43
44 protected Queue<PrefixTreeArraySearcher> pool
45 = new LinkedBlockingQueue<PrefixTreeArraySearcher>(MAX_POOL_SIZE);
46
47 public PrefixTreeArraySearcher checkOut(ByteBuffer buffer, boolean includesMvccVersion) {
48 PrefixTreeArraySearcher searcher = pool.poll();//will return null if pool is empty
49 searcher = DecoderFactory.ensureArraySearcherValid(buffer, searcher, includesMvccVersion);
50 return searcher;
51 }
52
53 public void checkIn(PrefixTreeArraySearcher searcher) {
54 searcher.releaseBlockReference();
55 pool.offer(searcher);
56 }
57
58 @Override
59 public String toString() {
60 return ("poolSize:" + pool.size());
61 }
62
63 }