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 * Returns the newly committed files from the flush. Called only if commit returns true 69 * @return a list of Paths for new files 70 */ 71 List<Path> getCommittedFiles(); 72 }