| /** |
| * 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.yetus.audience.InterfaceAudience; |
| |
| /** |
| * Consistency defines the expected consistency level for an operation. |
| */ |
| @InterfaceAudience.Public |
| 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, |
| } |