001/* 002 * Licensed to the Apache Software Foundation (ASF) under one 003 * or more contributor license agreements. See the NOTICE file 004 * distributed with this work for additional information 005 * regarding copyright ownership. The ASF licenses this file 006 * to you under the Apache License, Version 2.0 (the 007 * "License"); you may not use this file except in compliance 008 * with the License. You may obtain a copy of the License at 009 * 010 * http://www.apache.org/licenses/LICENSE-2.0 011 * 012 * Unless required by applicable law or agreed to in writing, software 013 * distributed under the License is distributed on an "AS IS" BASIS, 014 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 015 * See the License for the specific language governing permissions and 016 * limitations under the License. 017 */ 018package org.apache.hadoop.hbase.regionserver; 019 020import java.io.IOException; 021import java.util.List; 022import org.apache.hadoop.fs.Path; 023import org.apache.hadoop.hbase.monitoring.MonitoredTask; 024import org.apache.yetus.audience.InterfaceAudience; 025 026/** 027 * A package protected interface for a store flushing. A store flush context carries the state 028 * required to prepare/flush/commit the store's cache. 029 */ 030@InterfaceAudience.Private 031interface StoreFlushContext { 032 033 /** 034 * Prepare for a store flush (create snapshot) Requires pausing writes. A very short operation. 035 * @return The size of snapshot to flush 036 */ 037 MemStoreSize prepare(); 038 039 /** 040 * Flush the cache (create the new store file) A length operation which doesn't require locking 041 * out any function of the store. 042 * @throws IOException in case the flush fails 043 */ 044 void flushCache(MonitoredTask status) throws IOException; 045 046 /** 047 * Commit the flush - add the store file to the store and clear the memstore snapshot. Requires 048 * pausing scans. A very short operation 049 * @return whether compaction is required n 050 */ 051 boolean commit(MonitoredTask status) throws IOException; 052 053 /** 054 * Similar to commit, but called in secondary region replicas for replaying the flush cache from 055 * primary region. Adds the new files to the store, and drops the snapshot depending on 056 * dropMemstoreSnapshot argument. 057 * @param fileNames names of the flushed files 058 * @param dropMemstoreSnapshot whether to drop the prepared memstore snapshot n 059 */ 060 void replayFlush(List<String> fileNames, boolean dropMemstoreSnapshot) throws IOException; 061 062 /** 063 * Abort the snapshot preparation. Drops the snapshot if any. n 064 */ 065 void abort() throws IOException; 066 067 /** 068 * Returns the newly committed files from the flush. Called only if commit returns true 069 * @return a list of Paths for new files 070 */ 071 List<Path> getCommittedFiles(); 072 073 /** Returns the total file size for flush output files, in bytes */ 074 long getOutputFileSize(); 075}