org.apache.hadoop.hive.common.ValidReadTxnList Maven / Gradle / Ivy
/**
* 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 com.google.common.annotations.VisibleForTesting;
import java.util.Arrays;
/**
* An implementation of {@link org.apache.hadoop.hive.common.ValidTxnList} for use by readers.
* This class will view a transaction as valid only if it is committed. Both open and aborted
* transactions will be seen as invalid.
*/
public class ValidReadTxnList implements ValidTxnList {
protected long[] exceptions;
//default value means there are no open txn in the snapshot
private long minOpenTxn = Long.MAX_VALUE;
protected long highWatermark;
public ValidReadTxnList() {
this(new long[0], Long.MAX_VALUE, Long.MAX_VALUE);
}
/**
* Used if there are no open transactions in the snapshot
*/
public ValidReadTxnList(long[] exceptions, long highWatermark) {
this(exceptions, highWatermark, Long.MAX_VALUE);
}
public ValidReadTxnList(long[] exceptions, long highWatermark, long minOpenTxn) {
if (exceptions.length == 0) {
this.exceptions = exceptions;
} else {
this.exceptions = exceptions.clone();
Arrays.sort(this.exceptions);
this.minOpenTxn = minOpenTxn;
if(this.exceptions[0] <= 0) {
//should never happen of course
throw new IllegalArgumentException("Invalid txnid: " + this.exceptions[0] + " found");
}
}
this.highWatermark = highWatermark;
}
public ValidReadTxnList(String value) {
readFromString(value);
}
@Override
public boolean isTxnValid(long txnid) {
if (highWatermark < txnid) {
return false;
}
return Arrays.binarySearch(exceptions, txnid) < 0;
}
/**
* We cannot use a base file if its range contains an open txn.
* @param txnid from base_xxxx
*/
@Override
public boolean isValidBase(long txnid) {
return minOpenTxn > txnid && txnid <= highWatermark;
}
@Override
public RangeResponse isTxnRangeValid(long minTxnId, long maxTxnId) {
// check the easy cases first
if (highWatermark < minTxnId) {
return RangeResponse.NONE;
} else if (exceptions.length > 0 && exceptions[0] > maxTxnId) {
return RangeResponse.ALL;
}
// since the exceptions and the range in question overlap, count the
// exceptions in the range
long count = Math.max(0, maxTxnId - highWatermark);
for(long txn: exceptions) {
if (minTxnId <= txn && txn <= maxTxnId) {
count += 1;
}
}
if (count == 0) {
return RangeResponse.ALL;
} else if (count == (maxTxnId - minTxnId + 1)) {
return RangeResponse.NONE;
} else {
return RangeResponse.SOME;
}
}
@Override
public String toString() {
return writeToString();
}
@Override
public String writeToString() {
StringBuilder buf = new StringBuilder();
buf.append(highWatermark);
buf.append(':');
buf.append(minOpenTxn);
if (exceptions.length == 0) {
buf.append(':');
} else {
for(long except: exceptions) {
buf.append(':');
buf.append(except);
}
}
return buf.toString();
}
@Override
public void readFromString(String src) {
if (src == null || src.length() == 0) {
highWatermark = Long.MAX_VALUE;
exceptions = new long[0];
} else {
String[] values = src.split(":");
highWatermark = Long.parseLong(values[0]);
minOpenTxn = Long.parseLong(values[1]);
exceptions = new long[values.length - 2];
for(int i = 2; i < values.length; ++i) {
exceptions[i-2] = Long.parseLong(values[i]);
}
}
}
@Override
public long getHighWatermark() {
return highWatermark;
}
@Override
public long[] getInvalidTransactions() {
return exceptions;
}
@VisibleForTesting
public long getMinOpenTxn() {
return minOpenTxn;
}
}