/**
* 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.client;
import org.apache.hadoop.hbase.classification.InterfaceAudience;
import org.apache.hadoop.hbase.classification.InterfaceStability;
/**
* Consistency defines the expected consistency level for an operation.
*/
@InterfaceAudience.Public
@InterfaceStability.Evolving
public enum Consistency {
// developer note: Do not reorder. Client.proto#Consistency depends on this order
/**
* Strong consistency is the default consistency model in HBase,
* where reads and writes go through a single server which serializes
* the updates, and returns all data that was written and ack'd.
*/
STRONG,
/**
* Timeline consistent reads might return values that may not see
* the most recent updates. Write transactions are always performed
* in strong consistency model in HBase which guarantees that transactions
* are ordered, and replayed in the same order by all copies of the data.
* In timeline consistency, the get and scan requests can be answered from data
* that may be stale.
* <br>
* The client may still observe transactions out of order if the requests are
* responded from different servers.
*/
TIMELINE,
}