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.querymatcher; 019 020import java.io.IOException; 021import java.util.SortedSet; 022import java.util.TreeSet; 023import org.apache.hadoop.hbase.Cell; 024import org.apache.hadoop.hbase.CellComparator; 025import org.apache.hadoop.hbase.CellUtil; 026import org.apache.hadoop.hbase.KeyValue; 027import org.apache.hadoop.hbase.KeyValueUtil; 028import org.apache.hadoop.hbase.util.Bytes; 029import org.apache.yetus.audience.InterfaceAudience; 030 031/** 032 * This class is responsible for the tracking and enforcement of Deletes during the course of a Scan 033 * operation. It only has to enforce Delete and DeleteColumn, since the DeleteFamily is handled at a 034 * higher level. 035 * <p> 036 * This class is utilized through three methods: 037 * <ul> 038 * <li>{@link #add} when encountering a Delete or DeleteColumn</li> 039 * <li>{@link #isDeleted} when checking if a Put Cell has been deleted</li> 040 * <li>{@link #update} when reaching the end of a StoreFile or row for scans</li> 041 * </ul> 042 * <p> 043 * This class is NOT thread-safe as queries are never multi-threaded 044 */ 045@InterfaceAudience.Private 046public class ScanDeleteTracker implements DeleteTracker { 047 048 protected boolean hasFamilyStamp = false; 049 protected long familyStamp = 0L; 050 protected SortedSet<Long> familyVersionStamps = new TreeSet<Long>(); 051 protected Cell deleteCell = null; 052 protected byte[] deleteBuffer = null; 053 protected int deleteOffset = 0; 054 protected int deleteLength = 0; 055 protected byte deleteType = 0; 056 protected long deleteTimestamp = 0L; 057 protected final CellComparator comparator; 058 059 public ScanDeleteTracker(CellComparator comparator) { 060 this.comparator = comparator; 061 } 062 063 /** 064 * Add the specified Cell to the list of deletes to check against for this row operation. 065 * <p> 066 * This is called when a Delete is encountered. 067 * @param cell - the delete cell 068 */ 069 @Override 070 public void add(Cell cell) { 071 long timestamp = cell.getTimestamp(); 072 byte type = cell.getTypeByte(); 073 if (!hasFamilyStamp || timestamp > familyStamp) { 074 if (type == KeyValue.Type.DeleteFamily.getCode()) { 075 hasFamilyStamp = true; 076 familyStamp = timestamp; 077 return; 078 } else if (type == KeyValue.Type.DeleteFamilyVersion.getCode()) { 079 familyVersionStamps.add(timestamp); 080 return; 081 } 082 083 if (deleteCell != null && type < deleteType) { 084 // same column, so ignore less specific delete 085 if (CellUtil.matchingQualifier(cell, deleteCell)) { 086 return; 087 } 088 } 089 // new column, or more general delete type 090 deleteCell = cell; 091 deleteType = type; 092 deleteTimestamp = timestamp; 093 } 094 // missing else is never called. 095 } 096 097 /** 098 * Check if the specified Cell buffer has been deleted by a previously seen delete. 099 * @param cell - current cell to check if deleted by a previously seen delete n 100 */ 101 @Override 102 public DeleteResult isDeleted(Cell cell) { 103 long timestamp = cell.getTimestamp(); 104 if (hasFamilyStamp && timestamp <= familyStamp) { 105 return DeleteResult.FAMILY_DELETED; 106 } 107 108 if (familyVersionStamps.contains(Long.valueOf(timestamp))) { 109 return DeleteResult.FAMILY_VERSION_DELETED; 110 } 111 112 if (deleteCell != null) { 113 int ret = -(this.comparator.compareQualifiers(cell, deleteCell)); 114 if (ret == 0) { 115 if (deleteType == KeyValue.Type.DeleteColumn.getCode()) { 116 return DeleteResult.COLUMN_DELETED; 117 } 118 // Delete (aka DeleteVersion) 119 // If the timestamp is the same, keep this one 120 if (timestamp == deleteTimestamp) { 121 return DeleteResult.VERSION_DELETED; 122 } 123 // use assert or not? 124 assert timestamp < deleteTimestamp; 125 126 // different timestamp, let's clear the buffer. 127 deleteCell = null; 128 } else if (ret < 0) { 129 // Next column case. 130 deleteCell = null; 131 } else { 132 throw new IllegalStateException("isDelete failed: deleteBuffer=" 133 + Bytes.toStringBinary(deleteCell.getQualifierArray(), deleteCell.getQualifierOffset(), 134 deleteCell.getQualifierLength()) 135 + ", qualifier=" 136 + Bytes.toStringBinary(cell.getQualifierArray(), cell.getQualifierOffset(), 137 cell.getQualifierLength()) 138 + ", timestamp=" + timestamp + ", comparison result: " + ret); 139 } 140 } 141 142 return DeleteResult.NOT_DELETED; 143 } 144 145 @Override 146 public boolean isEmpty() { 147 return deleteCell == null && !hasFamilyStamp && familyVersionStamps.isEmpty(); 148 } 149 150 @Override 151 // called between every row. 152 public void reset() { 153 hasFamilyStamp = false; 154 familyStamp = 0L; 155 familyVersionStamps.clear(); 156 deleteCell = null; 157 } 158 159 @Override 160 // should not be called at all even (!) 161 public void update() { 162 this.reset(); 163 } 164 165 @Override 166 public void beforeShipped() throws IOException { 167 if (deleteCell != null) { 168 deleteCell = KeyValueUtil.toNewKeyCell(deleteCell); 169 } 170 } 171 172 @Override 173 public CellComparator getCellComparator() { 174 return this.comparator; 175 } 176}