| /** |
| * |
| * Licensed to the Apache Software Foundation (ASF) under one |
| * or more contributor license agreements. See the NOTICE file |
| * distributed with this work for additional information |
| * regarding copyright ownership. The ASF licenses this file |
| * to you under the Apache License, Version 2.0 (the |
| * "License"); you may not use this file except in compliance |
| * with the License. You may obtain a copy of the License at |
| * |
| * http://www.apache.org/licenses/LICENSE-2.0 |
| * |
| * Unless required by applicable law or agreed to in writing, software |
| * distributed under the License is distributed on an "AS IS" BASIS, |
| * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. |
| * See the License for the specific language governing permissions and |
| * limitations under the License. |
| */ |
| |
| package org.apache.hadoop.hbase.regionserver; |
| |
| import java.io.IOException; |
| |
| import org.apache.hadoop.hbase.classification.InterfaceAudience; |
| import org.apache.hadoop.hbase.Cell; |
| import org.apache.hadoop.hbase.CellComparator; |
| import org.apache.hadoop.hbase.CellUtil; |
| import org.apache.hadoop.hbase.HConstants; |
| import org.apache.hadoop.hbase.regionserver.ScanQueryMatcher.MatchCode; |
| import org.apache.hadoop.hbase.util.Bytes; |
| |
| /** |
| * Keeps track of the columns for a scan if they are not explicitly specified |
| */ |
| @InterfaceAudience.Private |
| public class ScanWildcardColumnTracker implements ColumnTracker { |
| private Cell columnCell = null; |
| private int currentCount = 0; |
| private int maxVersions; |
| private int minVersions; |
| /* Keeps track of the latest timestamp and type included for current column. |
| * Used to eliminate duplicates. */ |
| private long latestTSOfCurrentColumn; |
| private byte latestTypeOfCurrentColumn; |
| |
| private long oldestStamp; |
| |
| /** |
| * Return maxVersions of every row. |
| * @param minVersion Minimum number of versions to keep |
| * @param maxVersion Maximum number of versions to return |
| * @param oldestUnexpiredTS oldest timestamp that has not expired according |
| * to the TTL. |
| */ |
| public ScanWildcardColumnTracker(int minVersion, int maxVersion, |
| long oldestUnexpiredTS) { |
| this.maxVersions = maxVersion; |
| this.minVersions = minVersion; |
| this.oldestStamp = oldestUnexpiredTS; |
| } |
| |
| /** |
| * {@inheritDoc} |
| * This receives puts *and* deletes. |
| */ |
| @Override |
| public MatchCode checkColumn(Cell cell, byte type) throws IOException { |
| return MatchCode.INCLUDE; |
| } |
| |
| /** |
| * {@inheritDoc} |
| * This receives puts *and* deletes. Deletes do not count as a version, but rather |
| * take the version of the previous put (so eventually all but the last can be reclaimed). |
| */ |
| @Override |
| public ScanQueryMatcher.MatchCode checkVersions(Cell cell, |
| long timestamp, byte type, boolean ignoreCount) throws IOException { |
| |
| if (columnCell == null) { |
| // first iteration. |
| resetCell(cell); |
| if (ignoreCount) return ScanQueryMatcher.MatchCode.INCLUDE; |
| // do not count a delete marker as another version |
| return checkVersion(type, timestamp); |
| } |
| int cmp = CellComparator.compareQualifiers(cell, this.columnCell); |
| if (cmp == 0) { |
| if (ignoreCount) return ScanQueryMatcher.MatchCode.INCLUDE; |
| |
| //If column matches, check if it is a duplicate timestamp |
| if (sameAsPreviousTSAndType(timestamp, type)) { |
| return ScanQueryMatcher.MatchCode.SKIP; |
| } |
| return checkVersion(type, timestamp); |
| } |
| |
| resetTSAndType(); |
| |
| // new col > old col |
| if (cmp > 0) { |
| // switched columns, lets do something.x |
| resetCell(cell); |
| if (ignoreCount) return ScanQueryMatcher.MatchCode.INCLUDE; |
| return checkVersion(type, timestamp); |
| } |
| |
| // new col < oldcol |
| // WARNING: This means that very likely an edit for some other family |
| // was incorrectly stored into the store for this one. Throw an exception, |
| // because this might lead to data corruption. |
| throw new IOException( |
| "ScanWildcardColumnTracker.checkColumn ran into a column actually " + |
| "smaller than the previous column: " + |
| Bytes.toStringBinary(CellUtil.cloneQualifier(cell))); |
| } |
| |
| private void resetCell(Cell columnCell) { |
| this.columnCell = columnCell; |
| currentCount = 0; |
| } |
| |
| /** |
| * Check whether this version should be retained. |
| * There are 4 variables considered: |
| * If this version is past max versions -> skip it |
| * If this kv has expired or was deleted, check min versions |
| * to decide whther to skip it or not. |
| * |
| * Increase the version counter unless this is a delete |
| */ |
| private MatchCode checkVersion(byte type, long timestamp) { |
| if (!CellUtil.isDelete(type)) { |
| currentCount++; |
| } |
| if (currentCount > maxVersions) { |
| return ScanQueryMatcher.MatchCode.SEEK_NEXT_COL; // skip to next col |
| } |
| // keep the KV if required by minversions or it is not expired, yet |
| if (currentCount <= minVersions || !isExpired(timestamp)) { |
| setTSAndType(timestamp, type); |
| return ScanQueryMatcher.MatchCode.INCLUDE; |
| } else { |
| return MatchCode.SEEK_NEXT_COL; |
| } |
| |
| } |
| |
| @Override |
| public void reset() { |
| columnCell = null; |
| resetTSAndType(); |
| } |
| |
| private void resetTSAndType() { |
| latestTSOfCurrentColumn = HConstants.LATEST_TIMESTAMP; |
| latestTypeOfCurrentColumn = 0; |
| } |
| |
| private void setTSAndType(long timestamp, byte type) { |
| latestTSOfCurrentColumn = timestamp; |
| latestTypeOfCurrentColumn = type; |
| } |
| |
| private boolean sameAsPreviousTSAndType(long timestamp, byte type) { |
| return timestamp == latestTSOfCurrentColumn && type == latestTypeOfCurrentColumn; |
| } |
| |
| private boolean isExpired(long timestamp) { |
| return timestamp < oldestStamp; |
| } |
| |
| /** |
| * Used by matcher and scan/get to get a hint of the next column |
| * to seek to after checkColumn() returns SKIP. Returns the next interesting |
| * column we want, or NULL there is none (wildcard scanner). |
| * |
| * @return The column count. |
| */ |
| public ColumnCount getColumnHint() { |
| return null; |
| } |
| |
| /** |
| * We can never know a-priori if we are done, so always return false. |
| * @return false |
| */ |
| @Override |
| public boolean done() { |
| return false; |
| } |
| |
| @Override |
| public MatchCode getNextRowOrNextColumn(Cell cell) { |
| return MatchCode.SEEK_NEXT_COL; |
| } |
| |
| public boolean isDone(long timestamp) { |
| return minVersions <= 0 && isExpired(timestamp); |
| } |
| } |