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.ArrayList; 022import java.util.List; 023import java.util.NavigableSet; 024import org.apache.hadoop.hbase.ExtendedCell; 025import org.apache.hadoop.hbase.client.Scan; 026import org.apache.hadoop.hbase.mob.MobCell; 027import org.apache.hadoop.hbase.mob.MobUtils; 028import org.apache.yetus.audience.InterfaceAudience; 029import org.slf4j.Logger; 030import org.slf4j.LoggerFactory; 031 032/** 033 * Scanner scans both the memstore and the MOB Store. Coalesce KeyValue stream into 034 * {@code List<KeyValue>} for a single row. 035 */ 036@InterfaceAudience.Private 037public class MobStoreScanner extends StoreScanner { 038 039 private static final Logger LOG = LoggerFactory.getLogger(MobStoreScanner.class); 040 041 private boolean cacheMobBlocks = false; 042 private boolean rawMobScan = false; 043 private boolean readEmptyValueOnMobCellMiss = false; 044 private final HMobStore mobStore; 045 private final List<MobCell> referencedMobCells; 046 047 public MobStoreScanner(HStore store, ScanInfo scanInfo, Scan scan, 048 final NavigableSet<byte[]> columns, long readPt) throws IOException { 049 super(store, scanInfo, scan, columns, readPt); 050 cacheMobBlocks = MobUtils.isCacheMobBlocks(scan); 051 rawMobScan = MobUtils.isRawMobScan(scan); 052 readEmptyValueOnMobCellMiss = MobUtils.isReadEmptyValueOnMobCellMiss(scan); 053 if (!(store instanceof HMobStore)) { 054 throw new IllegalArgumentException("The store " + store + " is not a HMobStore"); 055 } 056 mobStore = (HMobStore) store; 057 this.referencedMobCells = new ArrayList<>(); 058 } 059 060 /** 061 * Firstly reads the cells from the HBase. If the cell are a reference cell (which has the 062 * reference tag), the scanner need seek this cell from the mob file, and use the cell found from 063 * the mob file as the result. 064 */ 065 @Override 066 public boolean next(List<? super ExtendedCell> outResult, ScannerContext ctx) throws IOException { 067 boolean result = super.next(outResult, ctx); 068 if (!rawMobScan) { 069 // retrieve the mob data 070 if (outResult.isEmpty()) { 071 return result; 072 } 073 long mobKVCount = 0; 074 long mobKVSize = 0; 075 for (int i = 0; i < outResult.size(); i++) { 076 // At server side, we should only get ExtendedCell 077 ExtendedCell cell = (ExtendedCell) outResult.get(i); 078 if (MobUtils.isMobReferenceCell(cell)) { 079 MobCell mobCell = 080 mobStore.resolve(cell, cacheMobBlocks, readPt, readEmptyValueOnMobCellMiss); 081 mobKVCount++; 082 mobKVSize += mobCell.getCell().getValueLength(); 083 outResult.set(i, mobCell.getCell()); 084 // Keep the MobCell here unless we shipped the RPC or close the scanner. 085 referencedMobCells.add(mobCell); 086 } 087 } 088 mobStore.updateMobScanCellsCount(mobKVCount); 089 mobStore.updateMobScanCellsSize(mobKVSize); 090 } 091 return result; 092 } 093 094 private void freeAllReferencedMobCells() throws IOException { 095 for (MobCell cell : referencedMobCells) { 096 cell.close(); 097 } 098 referencedMobCells.clear(); 099 } 100 101 @Override 102 public void shipped() throws IOException { 103 super.shipped(); 104 this.freeAllReferencedMobCells(); 105 } 106 107 @Override 108 public void close() { 109 super.close(); 110 try { 111 this.freeAllReferencedMobCells(); 112 } catch (IOException e) { 113 LOG.warn("Failed to free referenced mob cells: ", e); 114 } 115 } 116}