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.regionserver;
20
21 import java.io.IOException;
22 import java.util.List;
23
24 import org.apache.hadoop.hbase.classification.InterfaceAudience;
25 import org.apache.hadoop.fs.Path;
26 import org.apache.hadoop.hbase.monitoring.MonitoredTask;
27
28 /**
29 * A package protected interface for a store flushing.
30 * A store flush context carries the state required to prepare/flush/commit the store's cache.
31 */
32 @InterfaceAudience.Private
33 interface StoreFlushContext {
34
35 /**
36 * Prepare for a store flush (create snapshot)
37 *
38 * Requires pausing writes.
39 *
40 * A very short operation.
41 */
42 void prepare();
43
44 /**
45 * Flush the cache (create the new store file)
46 *
47 * A length operation which doesn't require locking out any function
48 * of the store.
49 *
50 * @throws IOException in case the flush fails
51 */
52 void flushCache(MonitoredTask status) throws IOException;
53
54 /**
55 * Commit the flush - add the store file to the store and clear the
56 * memstore snapshot.
57 *
58 * Requires pausing scans.
59 *
60 * A very short operation
61 *
62 * @return
63 * @throws IOException
64 */
65 boolean commit(MonitoredTask status) throws IOException;
66
67 /**
68 * Similar to commit, but called in secondary region replicas for replaying the
69 * flush cache from primary region. Adds the new files to the store, and drops the
70 * snapshot depending on dropMemstoreSnapshot argument.
71 * @param fileNames names of the flushed files
72 * @param dropMemstoreSnapshot whether to drop the prepared memstore snapshot
73 * @throws IOException
74 */
75 void replayFlush(List<String> fileNames, boolean dropMemstoreSnapshot) throws IOException;
76
77 /**
78 * Abort the snapshot preparation. Drops the snapshot if any.
79 * @throws IOException
80 */
81 void abort() throws IOException;
82
83 /**
84 * Returns the newly committed files from the flush. Called only if commit returns true
85 * @return a list of Paths for new files
86 */
87 List<Path> getCommittedFiles();
88 }