org.apache.hadoop.hive.common.ValidTxnList 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;
/**
* Models the list of transactions that should be included in a snapshot.
* It is modelled as a high water mark, which is the largest transaction id that
* has been committed and a list of transactions that are not included.
*/
public interface ValidTxnList {
/**
* Key used to store valid txn list in a
* {@link org.apache.hadoop.conf.Configuration} object.
*/
public static final String VALID_TXNS_KEY = "hive.txn.valid.txns";
/**
* The response to a range query. NONE means no values in this range match,
* SOME mean that some do, and ALL means that every value does.
*/
public enum RangeResponse {NONE, SOME, ALL};
/**
* Indicates whether a given transaction is valid. Note that valid may have different meanings
* for different implementations, as some will only want to see committed transactions and some
* both committed and aborted.
* @param txnid id for the transaction
* @return true if valid, false otherwise
*/
public boolean isTxnValid(long txnid);
/**
* Returns {@code true} if such base file can be used to materialize the snapshot represented by
* this {@code ValidTxnList}.
* @param txnid highest txn in a given base_xxxx file
*/
public boolean isValidBase(long txnid);
/**
* Find out if a range of transaction ids are valid. Note that valid may have different meanings
* for different implementations, as some will only want to see committed transactions and some
* both committed and aborted.
* @param minTxnId minimum txnid to look for, inclusive
* @param maxTxnId maximum txnid to look for, inclusive
* @return Indicate whether none, some, or all of these transactions are valid.
*/
public RangeResponse isTxnRangeValid(long minTxnId, long maxTxnId);
/**
* Write this validTxnList into a string. This should produce a string that
* can be used by {@link #readFromString(String)} to populate a validTxnsList.
*/
public String writeToString();
/**
* Populate this validTxnList from the string. It is assumed that the string
* was created via {@link #writeToString()}.
* @param src source string.
*/
public void readFromString(String src);
/**
* Get the largest transaction id used.
* @return largest transaction id used
*/
public long getHighWatermark();
/**
* Get the list of transactions under the high water mark that are not valid. Note that invalid
* may have different meanings for different implementations, as some will only want to see open
* transactions and some both open and aborted.
* @return a list of invalid transaction ids
*/
public long[] getInvalidTransactions();
}