org.apache.hadoop.hive.common.ValidCompactorTxnList Maven / Gradle / Ivy
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* 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.hive.common;
import java.util.Arrays;
/**
* An implementation of {@link org.apache.hadoop.hive.common.ValidTxnList} for use by the compactor.
*
* Compaction should only include txns up to smallest open txn (exclussive).
* There may be aborted txns in the snapshot represented by this ValidCompactorTxnList.
* Thus {@link #isTxnRangeValid(long, long)} returns NONE for any range that inluces any unresolved
* transactions. Any txn above {@code highWatermark} is unresolved.
* These produce the logic we need to assure that the compactor only sees records less than the lowest
* open transaction when choosing which files to compact, but that it still ignores aborted
* records when compacting.
*
* See {@link org.apache.hadoop.hive.metastore.txn.TxnUtils#createValidCompactTxnList()} for proper
* way to construct this.
*/
public class ValidCompactorTxnList extends ValidReadTxnList {
public ValidCompactorTxnList() {
super();
}
/**
* @param abortedTxnList list of all aborted transactions
* @param highWatermark highest committed transaction to be considered for compaction,
* equivalently (lowest_open_txn - 1).
*/
public ValidCompactorTxnList(long[] abortedTxnList, long highWatermark) {
super(abortedTxnList, highWatermark);
if(this.exceptions.length <= 0) {
return;
}
//now that exceptions (aka abortedTxnList) is sorted
int idx = Arrays.binarySearch(this.exceptions, highWatermark);
int lastElementPos;
if(idx < 0) {
int insertionPoint = -idx - 1 ;//see Arrays.binarySearch() JavaDoc
lastElementPos = insertionPoint - 1;
}
else {
lastElementPos = idx;
}
/**
* ensure that we throw out any exceptions above highWatermark to make
* {@link #isTxnValid(long)} faster
*/
this.exceptions = Arrays.copyOf(this.exceptions, lastElementPos + 1);
}
public ValidCompactorTxnList(String value) {
super(value);
}
/**
* Returns {@link org.apache.hadoop.hive.common.ValidTxnList.RangeResponse.ALL} if all txns in
* the range are resolved and RangeResponse.NONE otherwise
*/
@Override
public RangeResponse isTxnRangeValid(long minTxnId, long maxTxnId) {
return highWatermark >= maxTxnId ? RangeResponse.ALL : RangeResponse.NONE;
}
}