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<pre><span class="source-line-no">001</span><span id="line-1">/*</span>
<span class="source-line-no">002</span><span id="line-2"> * Licensed to the Apache Software Foundation (ASF) under one</span>
<span class="source-line-no">003</span><span id="line-3"> * or more contributor license agreements. See the NOTICE file</span>
<span class="source-line-no">004</span><span id="line-4"> * distributed with this work for additional information</span>
<span class="source-line-no">005</span><span id="line-5"> * regarding copyright ownership. The ASF licenses this file</span>
<span class="source-line-no">006</span><span id="line-6"> * to you under the Apache License, Version 2.0 (the</span>
<span class="source-line-no">007</span><span id="line-7"> * "License"); you may not use this file except in compliance</span>
<span class="source-line-no">008</span><span id="line-8"> * with the License. You may obtain a copy of the License at</span>
<span class="source-line-no">009</span><span id="line-9"> *</span>
<span class="source-line-no">010</span><span id="line-10"> * http://www.apache.org/licenses/LICENSE-2.0</span>
<span class="source-line-no">011</span><span id="line-11"> *</span>
<span class="source-line-no">012</span><span id="line-12"> * Unless required by applicable law or agreed to in writing, software</span>
<span class="source-line-no">013</span><span id="line-13"> * distributed under the License is distributed on an "AS IS" BASIS,</span>
<span class="source-line-no">014</span><span id="line-14"> * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.</span>
<span class="source-line-no">015</span><span id="line-15"> * See the License for the specific language governing permissions and</span>
<span class="source-line-no">016</span><span id="line-16"> * limitations under the License.</span>
<span class="source-line-no">017</span><span id="line-17"> */</span>
<span class="source-line-no">018</span><span id="line-18">package org.apache.hadoop.hbase.wal;</span>
<span class="source-line-no">019</span><span id="line-19"></span>
<span class="source-line-no">020</span><span id="line-20">import java.io.Closeable;</span>
<span class="source-line-no">021</span><span id="line-21">import java.io.IOException;</span>
<span class="source-line-no">022</span><span id="line-22">import java.util.List;</span>
<span class="source-line-no">023</span><span id="line-23">import java.util.OptionalLong;</span>
<span class="source-line-no">024</span><span id="line-24">import java.util.concurrent.CompletableFuture;</span>
<span class="source-line-no">025</span><span id="line-25">import org.apache.hadoop.conf.Configuration;</span>
<span class="source-line-no">026</span><span id="line-26">import org.apache.hadoop.hbase.Abortable;</span>
<span class="source-line-no">027</span><span id="line-27">import org.apache.hadoop.hbase.client.RegionInfo;</span>
<span class="source-line-no">028</span><span id="line-28">import org.apache.hadoop.hbase.regionserver.wal.AsyncFSWAL;</span>
<span class="source-line-no">029</span><span id="line-29">import org.apache.hadoop.hbase.regionserver.wal.WALActionsListener;</span>
<span class="source-line-no">030</span><span id="line-30">import org.apache.hadoop.hbase.replication.regionserver.PeerActionListener;</span>
<span class="source-line-no">031</span><span id="line-31">import org.apache.hadoop.hbase.replication.regionserver.SyncReplicationPeerInfoProvider;</span>
<span class="source-line-no">032</span><span id="line-32">import org.apache.hadoop.hbase.replication.regionserver.WALFileLengthProvider;</span>
<span class="source-line-no">033</span><span id="line-33">import org.apache.yetus.audience.InterfaceAudience;</span>
<span class="source-line-no">034</span><span id="line-34"></span>
<span class="source-line-no">035</span><span id="line-35">/**</span>
<span class="source-line-no">036</span><span id="line-36"> * The Write Ahead Log (WAL) stores all durable edits to the HRegion. This interface provides the</span>
<span class="source-line-no">037</span><span id="line-37"> * entry point for all WAL implementors.</span>
<span class="source-line-no">038</span><span id="line-38"> * &lt;p&gt;</span>
<span class="source-line-no">039</span><span id="line-39"> * See {@link FSHLogProvider} for an example implementation. A single WALProvider will be used for</span>
<span class="source-line-no">040</span><span id="line-40"> * retrieving multiple WALs in a particular region server and must be threadsafe.</span>
<span class="source-line-no">041</span><span id="line-41"> */</span>
<span class="source-line-no">042</span><span id="line-42">@InterfaceAudience.Private</span>
<span class="source-line-no">043</span><span id="line-43">public interface WALProvider {</span>
<span class="source-line-no">044</span><span id="line-44"></span>
<span class="source-line-no">045</span><span id="line-45"> /**</span>
<span class="source-line-no">046</span><span id="line-46"> * Set up the provider to create wals. will only be called once per instance.</span>
<span class="source-line-no">047</span><span id="line-47"> * @param factory factory that made us may not be null</span>
<span class="source-line-no">048</span><span id="line-48"> * @param conf may not be null</span>
<span class="source-line-no">049</span><span id="line-49"> * @param providerId differentiate between providers from one factory. may be null</span>
<span class="source-line-no">050</span><span id="line-50"> */</span>
<span class="source-line-no">051</span><span id="line-51"> void init(WALFactory factory, Configuration conf, String providerId, Abortable server)</span>
<span class="source-line-no">052</span><span id="line-52"> throws IOException;</span>
<span class="source-line-no">053</span><span id="line-53"></span>
<span class="source-line-no">054</span><span id="line-54"> /**</span>
<span class="source-line-no">055</span><span id="line-55"> * @param region the region which we want to get a WAL for it. Could be null.</span>
<span class="source-line-no">056</span><span id="line-56"> * @return a WAL for writing entries for the given region.</span>
<span class="source-line-no">057</span><span id="line-57"> */</span>
<span class="source-line-no">058</span><span id="line-58"> WAL getWAL(RegionInfo region) throws IOException;</span>
<span class="source-line-no">059</span><span id="line-59"></span>
<span class="source-line-no">060</span><span id="line-60"> /** Returns the List of WALs that are used by this server */</span>
<span class="source-line-no">061</span><span id="line-61"> List&lt;WAL&gt; getWALs();</span>
<span class="source-line-no">062</span><span id="line-62"></span>
<span class="source-line-no">063</span><span id="line-63"> /**</span>
<span class="source-line-no">064</span><span id="line-64"> * persist outstanding WALs to storage and stop accepting new appends. This method serves as</span>
<span class="source-line-no">065</span><span id="line-65"> * shorthand for sending a sync to every WAL provided by a given implementation. Those WALs will</span>
<span class="source-line-no">066</span><span id="line-66"> * also stop accepting new writes.</span>
<span class="source-line-no">067</span><span id="line-67"> */</span>
<span class="source-line-no">068</span><span id="line-68"> void shutdown() throws IOException;</span>
<span class="source-line-no">069</span><span id="line-69"></span>
<span class="source-line-no">070</span><span id="line-70"> /**</span>
<span class="source-line-no">071</span><span id="line-71"> * shutdown utstanding WALs and clean up any persisted state. Call this method only when you will</span>
<span class="source-line-no">072</span><span id="line-72"> * not need to replay any of the edits to the WALs from this provider. After this call completes,</span>
<span class="source-line-no">073</span><span id="line-73"> * the underlying resources should have been reclaimed.</span>
<span class="source-line-no">074</span><span id="line-74"> */</span>
<span class="source-line-no">075</span><span id="line-75"> void close() throws IOException;</span>
<span class="source-line-no">076</span><span id="line-76"></span>
<span class="source-line-no">077</span><span id="line-77"> interface WriterBase extends Closeable {</span>
<span class="source-line-no">078</span><span id="line-78"> long getLength();</span>
<span class="source-line-no">079</span><span id="line-79"></span>
<span class="source-line-no">080</span><span id="line-80"> /**</span>
<span class="source-line-no">081</span><span id="line-81"> * NOTE: We add this method for {@link WALFileLengthProvider} used for replication, considering</span>
<span class="source-line-no">082</span><span id="line-82"> * the case if we use {@link AsyncFSWAL},we write to 3 DNs concurrently, according to the</span>
<span class="source-line-no">083</span><span id="line-83"> * visibility guarantee of HDFS, the data will be available immediately when arriving at DN</span>
<span class="source-line-no">084</span><span id="line-84"> * since all the DNs will be considered as the last one in pipeline. This means replication may</span>
<span class="source-line-no">085</span><span id="line-85"> * read uncommitted data and replicate it to the remote cluster and cause data inconsistency.</span>
<span class="source-line-no">086</span><span id="line-86"> * The method {@link WriterBase#getLength} may return length which just in hdfs client buffer</span>
<span class="source-line-no">087</span><span id="line-87"> * and not successfully synced to HDFS, so we use this method to return the length successfully</span>
<span class="source-line-no">088</span><span id="line-88"> * synced to HDFS and replication thread could only read writing WAL file limited by this</span>
<span class="source-line-no">089</span><span id="line-89"> * length. see also HBASE-14004 and this document for more details:</span>
<span class="source-line-no">090</span><span id="line-90"> * https://docs.google.com/document/d/11AyWtGhItQs6vsLRIx32PwTxmBY3libXwGXI25obVEY/edit#</span>
<span class="source-line-no">091</span><span id="line-91"> * @return byteSize successfully synced to underlying filesystem.</span>
<span class="source-line-no">092</span><span id="line-92"> */</span>
<span class="source-line-no">093</span><span id="line-93"> long getSyncedLength();</span>
<span class="source-line-no">094</span><span id="line-94"> }</span>
<span class="source-line-no">095</span><span id="line-95"></span>
<span class="source-line-no">096</span><span id="line-96"> // Writers are used internally. Users outside of the WAL should be relying on the</span>
<span class="source-line-no">097</span><span id="line-97"> // interface provided by WAL.</span>
<span class="source-line-no">098</span><span id="line-98"> interface Writer extends WriterBase {</span>
<span class="source-line-no">099</span><span id="line-99"> void sync(boolean forceSync) throws IOException;</span>
<span class="source-line-no">100</span><span id="line-100"></span>
<span class="source-line-no">101</span><span id="line-101"> void append(WAL.Entry entry) throws IOException;</span>
<span class="source-line-no">102</span><span id="line-102"> }</span>
<span class="source-line-no">103</span><span id="line-103"></span>
<span class="source-line-no">104</span><span id="line-104"> interface AsyncWriter extends WriterBase {</span>
<span class="source-line-no">105</span><span id="line-105"> CompletableFuture&lt;Long&gt; sync(boolean forceSync);</span>
<span class="source-line-no">106</span><span id="line-106"></span>
<span class="source-line-no">107</span><span id="line-107"> void append(WAL.Entry entry);</span>
<span class="source-line-no">108</span><span id="line-108"> }</span>
<span class="source-line-no">109</span><span id="line-109"></span>
<span class="source-line-no">110</span><span id="line-110"> /**</span>
<span class="source-line-no">111</span><span id="line-111"> * Get number of the log files this provider is managing</span>
<span class="source-line-no">112</span><span id="line-112"> */</span>
<span class="source-line-no">113</span><span id="line-113"> long getNumLogFiles();</span>
<span class="source-line-no">114</span><span id="line-114"></span>
<span class="source-line-no">115</span><span id="line-115"> /**</span>
<span class="source-line-no">116</span><span id="line-116"> * Get size of the log files this provider is managing</span>
<span class="source-line-no">117</span><span id="line-117"> */</span>
<span class="source-line-no">118</span><span id="line-118"> long getLogFileSize();</span>
<span class="source-line-no">119</span><span id="line-119"></span>
<span class="source-line-no">120</span><span id="line-120"> /**</span>
<span class="source-line-no">121</span><span id="line-121"> * Add a {@link WALActionsListener}.</span>
<span class="source-line-no">122</span><span id="line-122"> * &lt;p&gt;</span>
<span class="source-line-no">123</span><span id="line-123"> * Notice that you must call this method before calling {@link #getWAL(RegionInfo)} as this method</span>
<span class="source-line-no">124</span><span id="line-124"> * will not effect the {@link WAL} which has already been created. And as long as we can only it</span>
<span class="source-line-no">125</span><span id="line-125"> * when initialization, it is not thread safe.</span>
<span class="source-line-no">126</span><span id="line-126"> */</span>
<span class="source-line-no">127</span><span id="line-127"> void addWALActionsListener(WALActionsListener listener);</span>
<span class="source-line-no">128</span><span id="line-128"></span>
<span class="source-line-no">129</span><span id="line-129"> default WALFileLengthProvider getWALFileLengthProvider() {</span>
<span class="source-line-no">130</span><span id="line-130"> return path -&gt; getWALs().stream().map(w -&gt; w.getLogFileSizeIfBeingWritten(path))</span>
<span class="source-line-no">131</span><span id="line-131"> .filter(o -&gt; o.isPresent()).findAny().orElse(OptionalLong.empty());</span>
<span class="source-line-no">132</span><span id="line-132"> }</span>
<span class="source-line-no">133</span><span id="line-133"></span>
<span class="source-line-no">134</span><span id="line-134"> // sync replication related</span>
<span class="source-line-no">135</span><span id="line-135"> default PeerActionListener getPeerActionListener() {</span>
<span class="source-line-no">136</span><span id="line-136"> return PeerActionListener.DUMMY;</span>
<span class="source-line-no">137</span><span id="line-137"> }</span>
<span class="source-line-no">138</span><span id="line-138"></span>
<span class="source-line-no">139</span><span id="line-139"> default void setSyncReplicationPeerInfoProvider(SyncReplicationPeerInfoProvider provider) {</span>
<span class="source-line-no">140</span><span id="line-140"> }</span>
<span class="source-line-no">141</span><span id="line-141">}</span>
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