org.apache.hive.common.util.TxnIdUtils Maven / Gradle / Ivy
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* 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,
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* See the License for the specific language governing permissions and
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*/
package org.apache.hive.common.util;
import org.apache.hadoop.hive.common.ValidWriteIdList;
public class TxnIdUtils {
/**
* Check if 2 ValidWriteIdLists are at an equivalent commit point.
*/
public static boolean checkEquivalentWriteIds(ValidWriteIdList a, ValidWriteIdList b) {
if (!a.getTableName().equalsIgnoreCase(b.getTableName())) {
return false;
}
ValidWriteIdList newer = a;
ValidWriteIdList older = b;
if (a.getHighWatermark() < b.getHighWatermark()) {
newer = b;
older = a;
}
return checkEquivalentCommittedIds(
older.getHighWatermark(), older.getInvalidWriteIds(),
newer.getHighWatermark(), newer.getInvalidWriteIds());
}
/**
* Check the min open ID/highwater mark/exceptions list to see if 2 ID lists are at the same commit point.
* This can also be used for ValidTxnList as well as ValidWriteIdList.
*/
private static boolean checkEquivalentCommittedIds(
long oldHWM, long[] oldInvalidIds,
long newHWM, long[] newInvalidIds) {
// There should be no valid txns in newer list that are not also in older.
// - All values in oldInvalidIds should also be in newInvalidIds.
// - if oldHWM < newHWM, then all IDs between oldHWM .. newHWM should exist in newInvalidTxns.
// A Gap in the sequence means a committed txn in newer list (lists are not equivalent)
if (newInvalidIds.length < oldInvalidIds.length) {
return false;
}
// Check that the values in the older list are also in newer. Lists should already be sorted.
for (int idx = 0; idx < oldInvalidIds.length; ++idx) {
if (oldInvalidIds[idx] != newInvalidIds[idx]) {
return false;
}
}
// If older committed state is equivalent to newer state, then there should be no committed IDs
// between oldHWM and newHWM, and newInvalidIds should have exactly (newHWM - oldHWM)
// more entries than oldInvalidIds.
long oldNewListSizeDifference = newInvalidIds.length - oldInvalidIds.length;
long oldNewHWMDifference = newHWM - oldHWM;
if (oldNewHWMDifference != oldNewListSizeDifference) {
return false;
}
return true;
}
}