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| <pre><span class="sourceLineNo">001</span>/*<a name="line.1"></a> |
| <span class="sourceLineNo">002</span> * Licensed to the Apache Software Foundation (ASF) under one<a name="line.2"></a> |
| <span class="sourceLineNo">003</span> * or more contributor license agreements. See the NOTICE file<a name="line.3"></a> |
| <span class="sourceLineNo">004</span> * distributed with this work for additional information<a name="line.4"></a> |
| <span class="sourceLineNo">005</span> * regarding copyright ownership. The ASF licenses this file<a name="line.5"></a> |
| <span class="sourceLineNo">006</span> * to you under the Apache License, Version 2.0 (the<a name="line.6"></a> |
| <span class="sourceLineNo">007</span> * "License"); you may not use this file except in compliance<a name="line.7"></a> |
| <span class="sourceLineNo">008</span> * with the License. You may obtain a copy of the License at<a name="line.8"></a> |
| <span class="sourceLineNo">009</span> *<a name="line.9"></a> |
| <span class="sourceLineNo">010</span> * http://www.apache.org/licenses/LICENSE-2.0<a name="line.10"></a> |
| <span class="sourceLineNo">011</span> *<a name="line.11"></a> |
| <span class="sourceLineNo">012</span> * Unless required by applicable law or agreed to in writing, software<a name="line.12"></a> |
| <span class="sourceLineNo">013</span> * distributed under the License is distributed on an "AS IS" BASIS,<a name="line.13"></a> |
| <span class="sourceLineNo">014</span> * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.<a name="line.14"></a> |
| <span class="sourceLineNo">015</span> * See the License for the specific language governing permissions and<a name="line.15"></a> |
| <span class="sourceLineNo">016</span> * limitations under the License.<a name="line.16"></a> |
| <span class="sourceLineNo">017</span> */<a name="line.17"></a> |
| <span class="sourceLineNo">018</span>package org.apache.hadoop.hbase.client.example;<a name="line.18"></a> |
| <span class="sourceLineNo">019</span><a name="line.19"></a> |
| <span class="sourceLineNo">020</span>import java.io.IOException;<a name="line.20"></a> |
| <span class="sourceLineNo">021</span>import java.util.ArrayList;<a name="line.21"></a> |
| <span class="sourceLineNo">022</span>import java.util.List;<a name="line.22"></a> |
| <span class="sourceLineNo">023</span>import java.util.concurrent.Callable;<a name="line.23"></a> |
| <span class="sourceLineNo">024</span>import java.util.concurrent.ExecutorService;<a name="line.24"></a> |
| <span class="sourceLineNo">025</span>import java.util.concurrent.Executors;<a name="line.25"></a> |
| <span class="sourceLineNo">026</span>import java.util.concurrent.ForkJoinPool;<a name="line.26"></a> |
| <span class="sourceLineNo">027</span>import java.util.concurrent.Future;<a name="line.27"></a> |
| <span class="sourceLineNo">028</span>import java.util.concurrent.ThreadFactory;<a name="line.28"></a> |
| <span class="sourceLineNo">029</span>import java.util.concurrent.ThreadLocalRandom;<a name="line.29"></a> |
| <span class="sourceLineNo">030</span>import java.util.concurrent.TimeUnit;<a name="line.30"></a> |
| <span class="sourceLineNo">031</span>import org.apache.hadoop.conf.Configured;<a name="line.31"></a> |
| <span class="sourceLineNo">032</span>import org.apache.hadoop.hbase.Cell;<a name="line.32"></a> |
| <span class="sourceLineNo">033</span>import org.apache.hadoop.hbase.Cell.Type;<a name="line.33"></a> |
| <span class="sourceLineNo">034</span>import org.apache.hadoop.hbase.CellBuilderFactory;<a name="line.34"></a> |
| <span class="sourceLineNo">035</span>import org.apache.hadoop.hbase.CellBuilderType;<a name="line.35"></a> |
| <span class="sourceLineNo">036</span>import org.apache.hadoop.hbase.TableName;<a name="line.36"></a> |
| <span class="sourceLineNo">037</span>import org.apache.hadoop.hbase.client.Connection;<a name="line.37"></a> |
| <span class="sourceLineNo">038</span>import org.apache.hadoop.hbase.client.ConnectionFactory;<a name="line.38"></a> |
| <span class="sourceLineNo">039</span>import org.apache.hadoop.hbase.client.Put;<a name="line.39"></a> |
| <span class="sourceLineNo">040</span>import org.apache.hadoop.hbase.client.RegionLocator;<a name="line.40"></a> |
| <span class="sourceLineNo">041</span>import org.apache.hadoop.hbase.client.Result;<a name="line.41"></a> |
| <span class="sourceLineNo">042</span>import org.apache.hadoop.hbase.client.ResultScanner;<a name="line.42"></a> |
| <span class="sourceLineNo">043</span>import org.apache.hadoop.hbase.client.Scan;<a name="line.43"></a> |
| <span class="sourceLineNo">044</span>import org.apache.hadoop.hbase.client.Table;<a name="line.44"></a> |
| <span class="sourceLineNo">045</span>import org.apache.hadoop.hbase.filter.KeyOnlyFilter;<a name="line.45"></a> |
| <span class="sourceLineNo">046</span>import org.apache.hadoop.hbase.util.Bytes;<a name="line.46"></a> |
| <span class="sourceLineNo">047</span>import org.apache.hadoop.util.Tool;<a name="line.47"></a> |
| <span class="sourceLineNo">048</span>import org.apache.hadoop.util.ToolRunner;<a name="line.48"></a> |
| <span class="sourceLineNo">049</span>import org.apache.yetus.audience.InterfaceAudience;<a name="line.49"></a> |
| <span class="sourceLineNo">050</span>import org.slf4j.Logger;<a name="line.50"></a> |
| <span class="sourceLineNo">051</span>import org.slf4j.LoggerFactory;<a name="line.51"></a> |
| <span class="sourceLineNo">052</span><a name="line.52"></a> |
| <span class="sourceLineNo">053</span>import org.apache.hbase.thirdparty.com.google.common.util.concurrent.ThreadFactoryBuilder;<a name="line.53"></a> |
| <span class="sourceLineNo">054</span><a name="line.54"></a> |
| <span class="sourceLineNo">055</span>/**<a name="line.55"></a> |
| <span class="sourceLineNo">056</span> * Example on how to use HBase's {@link Connection} and {@link Table} in a multi-threaded<a name="line.56"></a> |
| <span class="sourceLineNo">057</span> * environment. Each table is a light weight object that is created and thrown away. Connections are<a name="line.57"></a> |
| <span class="sourceLineNo">058</span> * heavy weight objects that hold on to zookeeper connections, async processes, and other state.<a name="line.58"></a> |
| <span class="sourceLineNo">059</span> *<a name="line.59"></a> |
| <span class="sourceLineNo">060</span> * <pre><a name="line.60"></a> |
| <span class="sourceLineNo">061</span> * Usage:<a name="line.61"></a> |
| <span class="sourceLineNo">062</span> * bin/hbase org.apache.hadoop.hbase.client.example.MultiThreadedClientExample testTableName 500000<a name="line.62"></a> |
| <span class="sourceLineNo">063</span> * </pre><a name="line.63"></a> |
| <span class="sourceLineNo">064</span> * <p><a name="line.64"></a> |
| <span class="sourceLineNo">065</span> * The table should already be created before running the command. This example expects one column<a name="line.65"></a> |
| <span class="sourceLineNo">066</span> * family named d.<a name="line.66"></a> |
| <span class="sourceLineNo">067</span> * </p><a name="line.67"></a> |
| <span class="sourceLineNo">068</span> * <p><a name="line.68"></a> |
| <span class="sourceLineNo">069</span> * This is meant to show different operations that are likely to be done in a real world<a name="line.69"></a> |
| <span class="sourceLineNo">070</span> * application. These operations are:<a name="line.70"></a> |
| <span class="sourceLineNo">071</span> * </p><a name="line.71"></a> |
| <span class="sourceLineNo">072</span> * <ul><a name="line.72"></a> |
| <span class="sourceLineNo">073</span> * <li>30% of all operations performed are batch writes. 30 puts are created and sent out at a time.<a name="line.73"></a> |
| <span class="sourceLineNo">074</span> * The response for all puts is waited on.</li><a name="line.74"></a> |
| <span class="sourceLineNo">075</span> * <li>20% of all operations are single writes. A single put is sent out and the response is waited<a name="line.75"></a> |
| <span class="sourceLineNo">076</span> * for.</li><a name="line.76"></a> |
| <span class="sourceLineNo">077</span> * <li>50% of all operations are scans. These scans start at a random place and scan up to 100 rows.<a name="line.77"></a> |
| <span class="sourceLineNo">078</span> * </li><a name="line.78"></a> |
| <span class="sourceLineNo">079</span> * </ul><a name="line.79"></a> |
| <span class="sourceLineNo">080</span> */<a name="line.80"></a> |
| <span class="sourceLineNo">081</span>@InterfaceAudience.Private<a name="line.81"></a> |
| <span class="sourceLineNo">082</span>public class MultiThreadedClientExample extends Configured implements Tool {<a name="line.82"></a> |
| <span class="sourceLineNo">083</span> private static final Logger LOG = LoggerFactory.getLogger(MultiThreadedClientExample.class);<a name="line.83"></a> |
| <span class="sourceLineNo">084</span> private static final int DEFAULT_NUM_OPERATIONS = 500000;<a name="line.84"></a> |
| <span class="sourceLineNo">085</span><a name="line.85"></a> |
| <span class="sourceLineNo">086</span> /**<a name="line.86"></a> |
| <span class="sourceLineNo">087</span> * The name of the column family. d for default.<a name="line.87"></a> |
| <span class="sourceLineNo">088</span> */<a name="line.88"></a> |
| <span class="sourceLineNo">089</span> private static final byte[] FAMILY = Bytes.toBytes("d");<a name="line.89"></a> |
| <span class="sourceLineNo">090</span><a name="line.90"></a> |
| <span class="sourceLineNo">091</span> /**<a name="line.91"></a> |
| <span class="sourceLineNo">092</span> * For the example we're just using one qualifier.<a name="line.92"></a> |
| <span class="sourceLineNo">093</span> */<a name="line.93"></a> |
| <span class="sourceLineNo">094</span> private static final byte[] QUAL = Bytes.toBytes("test");<a name="line.94"></a> |
| <span class="sourceLineNo">095</span><a name="line.95"></a> |
| <span class="sourceLineNo">096</span> private final ExecutorService internalPool;<a name="line.96"></a> |
| <span class="sourceLineNo">097</span><a name="line.97"></a> |
| <span class="sourceLineNo">098</span> private final int threads;<a name="line.98"></a> |
| <span class="sourceLineNo">099</span><a name="line.99"></a> |
| <span class="sourceLineNo">100</span> public MultiThreadedClientExample() throws IOException {<a name="line.100"></a> |
| <span class="sourceLineNo">101</span> // Base number of threads.<a name="line.101"></a> |
| <span class="sourceLineNo">102</span> // This represents the number of threads you application has<a name="line.102"></a> |
| <span class="sourceLineNo">103</span> // that can be interacting with an hbase client.<a name="line.103"></a> |
| <span class="sourceLineNo">104</span> this.threads = Runtime.getRuntime().availableProcessors() * 4;<a name="line.104"></a> |
| <span class="sourceLineNo">105</span><a name="line.105"></a> |
| <span class="sourceLineNo">106</span> // Daemon threads are great for things that get shut down.<a name="line.106"></a> |
| <span class="sourceLineNo">107</span> ThreadFactory threadFactory =<a name="line.107"></a> |
| <span class="sourceLineNo">108</span> new ThreadFactoryBuilder().setDaemon(true).setNameFormat("internal-pol-%d").build();<a name="line.108"></a> |
| <span class="sourceLineNo">109</span><a name="line.109"></a> |
| <span class="sourceLineNo">110</span> this.internalPool = Executors.newFixedThreadPool(threads, threadFactory);<a name="line.110"></a> |
| <span class="sourceLineNo">111</span> }<a name="line.111"></a> |
| <span class="sourceLineNo">112</span><a name="line.112"></a> |
| <span class="sourceLineNo">113</span> @Override<a name="line.113"></a> |
| <span class="sourceLineNo">114</span> public int run(String[] args) throws Exception {<a name="line.114"></a> |
| <span class="sourceLineNo">115</span><a name="line.115"></a> |
| <span class="sourceLineNo">116</span> if (args.length < 1 || args.length > 2) {<a name="line.116"></a> |
| <span class="sourceLineNo">117</span> System.out.println("Usage: " + this.getClass().getName() + " tableName [num_operations]");<a name="line.117"></a> |
| <span class="sourceLineNo">118</span> return -1;<a name="line.118"></a> |
| <span class="sourceLineNo">119</span> }<a name="line.119"></a> |
| <span class="sourceLineNo">120</span><a name="line.120"></a> |
| <span class="sourceLineNo">121</span> final TableName tableName = TableName.valueOf(args[0]);<a name="line.121"></a> |
| <span class="sourceLineNo">122</span> int numOperations = DEFAULT_NUM_OPERATIONS;<a name="line.122"></a> |
| <span class="sourceLineNo">123</span><a name="line.123"></a> |
| <span class="sourceLineNo">124</span> // the second arg is the number of operations to send.<a name="line.124"></a> |
| <span class="sourceLineNo">125</span> if (args.length == 2) {<a name="line.125"></a> |
| <span class="sourceLineNo">126</span> numOperations = Integer.parseInt(args[1]);<a name="line.126"></a> |
| <span class="sourceLineNo">127</span> }<a name="line.127"></a> |
| <span class="sourceLineNo">128</span><a name="line.128"></a> |
| <span class="sourceLineNo">129</span> // Threads for the client only.<a name="line.129"></a> |
| <span class="sourceLineNo">130</span> //<a name="line.130"></a> |
| <span class="sourceLineNo">131</span> // We don't want to mix hbase and business logic.<a name="line.131"></a> |
| <span class="sourceLineNo">132</span> //<a name="line.132"></a> |
| <span class="sourceLineNo">133</span> ExecutorService service = new ForkJoinPool(threads * 2);<a name="line.133"></a> |
| <span class="sourceLineNo">134</span><a name="line.134"></a> |
| <span class="sourceLineNo">135</span> // Create two different connections showing how it's possible to<a name="line.135"></a> |
| <span class="sourceLineNo">136</span> // separate different types of requests onto different connections<a name="line.136"></a> |
| <span class="sourceLineNo">137</span> final Connection writeConnection = ConnectionFactory.createConnection(getConf(), service);<a name="line.137"></a> |
| <span class="sourceLineNo">138</span> final Connection readConnection = ConnectionFactory.createConnection(getConf(), service);<a name="line.138"></a> |
| <span class="sourceLineNo">139</span><a name="line.139"></a> |
| <span class="sourceLineNo">140</span> // At this point the entire cache for the region locations is full.<a name="line.140"></a> |
| <span class="sourceLineNo">141</span> // Only do this if the number of regions in a table is easy to fit into memory.<a name="line.141"></a> |
| <span class="sourceLineNo">142</span> //<a name="line.142"></a> |
| <span class="sourceLineNo">143</span> // If you are interacting with more than 25k regions on a client then it's probably not good<a name="line.143"></a> |
| <span class="sourceLineNo">144</span> // to do this at all.<a name="line.144"></a> |
| <span class="sourceLineNo">145</span> warmUpConnectionCache(readConnection, tableName);<a name="line.145"></a> |
| <span class="sourceLineNo">146</span> warmUpConnectionCache(writeConnection, tableName);<a name="line.146"></a> |
| <span class="sourceLineNo">147</span><a name="line.147"></a> |
| <span class="sourceLineNo">148</span> List<Future<Boolean>> futures = new ArrayList<>(numOperations);<a name="line.148"></a> |
| <span class="sourceLineNo">149</span> for (int i = 0; i < numOperations; i++) {<a name="line.149"></a> |
| <span class="sourceLineNo">150</span> double r = ThreadLocalRandom.current().nextDouble();<a name="line.150"></a> |
| <span class="sourceLineNo">151</span> Future<Boolean> f;<a name="line.151"></a> |
| <span class="sourceLineNo">152</span><a name="line.152"></a> |
| <span class="sourceLineNo">153</span> // For the sake of generating some synthetic load this queues<a name="line.153"></a> |
| <span class="sourceLineNo">154</span> // some different callables.<a name="line.154"></a> |
| <span class="sourceLineNo">155</span> // These callables are meant to represent real work done by your application.<a name="line.155"></a> |
| <span class="sourceLineNo">156</span> if (r < .30) {<a name="line.156"></a> |
| <span class="sourceLineNo">157</span> f = internalPool.submit(new WriteExampleCallable(writeConnection, tableName));<a name="line.157"></a> |
| <span class="sourceLineNo">158</span> } else if (r < .50) {<a name="line.158"></a> |
| <span class="sourceLineNo">159</span> f = internalPool.submit(new SingleWriteExampleCallable(writeConnection, tableName));<a name="line.159"></a> |
| <span class="sourceLineNo">160</span> } else {<a name="line.160"></a> |
| <span class="sourceLineNo">161</span> f = internalPool.submit(new ReadExampleCallable(writeConnection, tableName));<a name="line.161"></a> |
| <span class="sourceLineNo">162</span> }<a name="line.162"></a> |
| <span class="sourceLineNo">163</span> futures.add(f);<a name="line.163"></a> |
| <span class="sourceLineNo">164</span> }<a name="line.164"></a> |
| <span class="sourceLineNo">165</span><a name="line.165"></a> |
| <span class="sourceLineNo">166</span> // Wait a long time for all the reads/writes to complete<a name="line.166"></a> |
| <span class="sourceLineNo">167</span> for (Future<Boolean> f : futures) {<a name="line.167"></a> |
| <span class="sourceLineNo">168</span> f.get(10, TimeUnit.MINUTES);<a name="line.168"></a> |
| <span class="sourceLineNo">169</span> }<a name="line.169"></a> |
| <span class="sourceLineNo">170</span><a name="line.170"></a> |
| <span class="sourceLineNo">171</span> // Clean up after our selves for cleanliness<a name="line.171"></a> |
| <span class="sourceLineNo">172</span> internalPool.shutdownNow();<a name="line.172"></a> |
| <span class="sourceLineNo">173</span> service.shutdownNow();<a name="line.173"></a> |
| <span class="sourceLineNo">174</span> return 0;<a name="line.174"></a> |
| <span class="sourceLineNo">175</span> }<a name="line.175"></a> |
| <span class="sourceLineNo">176</span><a name="line.176"></a> |
| <span class="sourceLineNo">177</span> private void warmUpConnectionCache(Connection connection, TableName tn) throws IOException {<a name="line.177"></a> |
| <span class="sourceLineNo">178</span> try (RegionLocator locator = connection.getRegionLocator(tn)) {<a name="line.178"></a> |
| <span class="sourceLineNo">179</span> LOG.info("Warmed up region location cache for " + tn + " got "<a name="line.179"></a> |
| <span class="sourceLineNo">180</span> + locator.getAllRegionLocations().size());<a name="line.180"></a> |
| <span class="sourceLineNo">181</span> }<a name="line.181"></a> |
| <span class="sourceLineNo">182</span> }<a name="line.182"></a> |
| <span class="sourceLineNo">183</span><a name="line.183"></a> |
| <span class="sourceLineNo">184</span> /**<a name="line.184"></a> |
| <span class="sourceLineNo">185</span> * Class that will show how to send batches of puts at the same time.<a name="line.185"></a> |
| <span class="sourceLineNo">186</span> */<a name="line.186"></a> |
| <span class="sourceLineNo">187</span> public static class WriteExampleCallable implements Callable<Boolean> {<a name="line.187"></a> |
| <span class="sourceLineNo">188</span> private final Connection connection;<a name="line.188"></a> |
| <span class="sourceLineNo">189</span> private final TableName tableName;<a name="line.189"></a> |
| <span class="sourceLineNo">190</span><a name="line.190"></a> |
| <span class="sourceLineNo">191</span> public WriteExampleCallable(Connection connection, TableName tableName) {<a name="line.191"></a> |
| <span class="sourceLineNo">192</span> this.connection = connection;<a name="line.192"></a> |
| <span class="sourceLineNo">193</span> this.tableName = tableName;<a name="line.193"></a> |
| <span class="sourceLineNo">194</span> }<a name="line.194"></a> |
| <span class="sourceLineNo">195</span><a name="line.195"></a> |
| <span class="sourceLineNo">196</span> @Override<a name="line.196"></a> |
| <span class="sourceLineNo">197</span> public Boolean call() throws Exception {<a name="line.197"></a> |
| <span class="sourceLineNo">198</span><a name="line.198"></a> |
| <span class="sourceLineNo">199</span> // Table implements Closable so we use the try with resource structure here.<a name="line.199"></a> |
| <span class="sourceLineNo">200</span> // https://docs.oracle.com/javase/tutorial/essential/exceptions/tryResourceClose.html<a name="line.200"></a> |
| <span class="sourceLineNo">201</span> try (Table t = connection.getTable(tableName)) {<a name="line.201"></a> |
| <span class="sourceLineNo">202</span> byte[] value = Bytes.toBytes(Double.toString(ThreadLocalRandom.current().nextDouble()));<a name="line.202"></a> |
| <span class="sourceLineNo">203</span> int rows = 30;<a name="line.203"></a> |
| <span class="sourceLineNo">204</span><a name="line.204"></a> |
| <span class="sourceLineNo">205</span> // Array to put the batch<a name="line.205"></a> |
| <span class="sourceLineNo">206</span> ArrayList<Put> puts = new ArrayList<>(rows);<a name="line.206"></a> |
| <span class="sourceLineNo">207</span> for (int i = 0; i < 30; i++) {<a name="line.207"></a> |
| <span class="sourceLineNo">208</span> byte[] rk = Bytes.toBytes(ThreadLocalRandom.current().nextLong());<a name="line.208"></a> |
| <span class="sourceLineNo">209</span> Put p = new Put(rk);<a name="line.209"></a> |
| <span class="sourceLineNo">210</span> p.add(CellBuilderFactory.create(CellBuilderType.SHALLOW_COPY).setRow(rk).setFamily(FAMILY)<a name="line.210"></a> |
| <span class="sourceLineNo">211</span> .setQualifier(QUAL).setTimestamp(p.getTimestamp()).setType(Cell.Type.Put)<a name="line.211"></a> |
| <span class="sourceLineNo">212</span> .setValue(value).build());<a name="line.212"></a> |
| <span class="sourceLineNo">213</span> puts.add(p);<a name="line.213"></a> |
| <span class="sourceLineNo">214</span> }<a name="line.214"></a> |
| <span class="sourceLineNo">215</span><a name="line.215"></a> |
| <span class="sourceLineNo">216</span> // now that we've assembled the batch it's time to push it to hbase.<a name="line.216"></a> |
| <span class="sourceLineNo">217</span> t.put(puts);<a name="line.217"></a> |
| <span class="sourceLineNo">218</span> }<a name="line.218"></a> |
| <span class="sourceLineNo">219</span> return true;<a name="line.219"></a> |
| <span class="sourceLineNo">220</span> }<a name="line.220"></a> |
| <span class="sourceLineNo">221</span> }<a name="line.221"></a> |
| <span class="sourceLineNo">222</span><a name="line.222"></a> |
| <span class="sourceLineNo">223</span> /**<a name="line.223"></a> |
| <span class="sourceLineNo">224</span> * Class to show how to send a single put.<a name="line.224"></a> |
| <span class="sourceLineNo">225</span> */<a name="line.225"></a> |
| <span class="sourceLineNo">226</span> public static class SingleWriteExampleCallable implements Callable<Boolean> {<a name="line.226"></a> |
| <span class="sourceLineNo">227</span> private final Connection connection;<a name="line.227"></a> |
| <span class="sourceLineNo">228</span> private final TableName tableName;<a name="line.228"></a> |
| <span class="sourceLineNo">229</span><a name="line.229"></a> |
| <span class="sourceLineNo">230</span> public SingleWriteExampleCallable(Connection connection, TableName tableName) {<a name="line.230"></a> |
| <span class="sourceLineNo">231</span> this.connection = connection;<a name="line.231"></a> |
| <span class="sourceLineNo">232</span> this.tableName = tableName;<a name="line.232"></a> |
| <span class="sourceLineNo">233</span> }<a name="line.233"></a> |
| <span class="sourceLineNo">234</span><a name="line.234"></a> |
| <span class="sourceLineNo">235</span> @Override<a name="line.235"></a> |
| <span class="sourceLineNo">236</span> public Boolean call() throws Exception {<a name="line.236"></a> |
| <span class="sourceLineNo">237</span> try (Table t = connection.getTable(tableName)) {<a name="line.237"></a> |
| <span class="sourceLineNo">238</span><a name="line.238"></a> |
| <span class="sourceLineNo">239</span> byte[] value = Bytes.toBytes(Double.toString(ThreadLocalRandom.current().nextDouble()));<a name="line.239"></a> |
| <span class="sourceLineNo">240</span> byte[] rk = Bytes.toBytes(ThreadLocalRandom.current().nextLong());<a name="line.240"></a> |
| <span class="sourceLineNo">241</span> Put p = new Put(rk);<a name="line.241"></a> |
| <span class="sourceLineNo">242</span> p.add(CellBuilderFactory.create(CellBuilderType.SHALLOW_COPY).setRow(rk).setFamily(FAMILY)<a name="line.242"></a> |
| <span class="sourceLineNo">243</span> .setQualifier(QUAL).setTimestamp(p.getTimestamp()).setType(Type.Put).setValue(value)<a name="line.243"></a> |
| <span class="sourceLineNo">244</span> .build());<a name="line.244"></a> |
| <span class="sourceLineNo">245</span> t.put(p);<a name="line.245"></a> |
| <span class="sourceLineNo">246</span> }<a name="line.246"></a> |
| <span class="sourceLineNo">247</span> return true;<a name="line.247"></a> |
| <span class="sourceLineNo">248</span> }<a name="line.248"></a> |
| <span class="sourceLineNo">249</span> }<a name="line.249"></a> |
| <span class="sourceLineNo">250</span><a name="line.250"></a> |
| <span class="sourceLineNo">251</span> /**<a name="line.251"></a> |
| <span class="sourceLineNo">252</span> * Class to show how to scan some rows starting at a random location.<a name="line.252"></a> |
| <span class="sourceLineNo">253</span> */<a name="line.253"></a> |
| <span class="sourceLineNo">254</span> public static class ReadExampleCallable implements Callable<Boolean> {<a name="line.254"></a> |
| <span class="sourceLineNo">255</span> private final Connection connection;<a name="line.255"></a> |
| <span class="sourceLineNo">256</span> private final TableName tableName;<a name="line.256"></a> |
| <span class="sourceLineNo">257</span><a name="line.257"></a> |
| <span class="sourceLineNo">258</span> public ReadExampleCallable(Connection connection, TableName tableName) {<a name="line.258"></a> |
| <span class="sourceLineNo">259</span> this.connection = connection;<a name="line.259"></a> |
| <span class="sourceLineNo">260</span> this.tableName = tableName;<a name="line.260"></a> |
| <span class="sourceLineNo">261</span> }<a name="line.261"></a> |
| <span class="sourceLineNo">262</span><a name="line.262"></a> |
| <span class="sourceLineNo">263</span> @Override<a name="line.263"></a> |
| <span class="sourceLineNo">264</span> public Boolean call() throws Exception {<a name="line.264"></a> |
| <span class="sourceLineNo">265</span><a name="line.265"></a> |
| <span class="sourceLineNo">266</span> // total length in bytes of all read rows.<a name="line.266"></a> |
| <span class="sourceLineNo">267</span> int result = 0;<a name="line.267"></a> |
| <span class="sourceLineNo">268</span><a name="line.268"></a> |
| <span class="sourceLineNo">269</span> // Number of rows the scan will read before being considered done.<a name="line.269"></a> |
| <span class="sourceLineNo">270</span> int toRead = 100;<a name="line.270"></a> |
| <span class="sourceLineNo">271</span> try (Table t = connection.getTable(tableName)) {<a name="line.271"></a> |
| <span class="sourceLineNo">272</span> byte[] rk = Bytes.toBytes(ThreadLocalRandom.current().nextLong());<a name="line.272"></a> |
| <span class="sourceLineNo">273</span> Scan s = new Scan().withStartRow(rk);<a name="line.273"></a> |
| <span class="sourceLineNo">274</span><a name="line.274"></a> |
| <span class="sourceLineNo">275</span> // This filter will keep the values from being sent accross the wire.<a name="line.275"></a> |
| <span class="sourceLineNo">276</span> // This is good for counting or other scans that are checking for<a name="line.276"></a> |
| <span class="sourceLineNo">277</span> // existence and don't rely on the value.<a name="line.277"></a> |
| <span class="sourceLineNo">278</span> s.setFilter(new KeyOnlyFilter());<a name="line.278"></a> |
| <span class="sourceLineNo">279</span><a name="line.279"></a> |
| <span class="sourceLineNo">280</span> // Don't go back to the server for every single row.<a name="line.280"></a> |
| <span class="sourceLineNo">281</span> // We know these rows are small. So ask for 20 at a time.<a name="line.281"></a> |
| <span class="sourceLineNo">282</span> // This would be application specific.<a name="line.282"></a> |
| <span class="sourceLineNo">283</span> //<a name="line.283"></a> |
| <span class="sourceLineNo">284</span> // The goal is to reduce round trips but asking for too<a name="line.284"></a> |
| <span class="sourceLineNo">285</span> // many rows can lead to GC problems on client and server sides.<a name="line.285"></a> |
| <span class="sourceLineNo">286</span> s.setCaching(20);<a name="line.286"></a> |
| <span class="sourceLineNo">287</span><a name="line.287"></a> |
| <span class="sourceLineNo">288</span> // Don't use the cache. While this is a silly test program it's still good to be<a name="line.288"></a> |
| <span class="sourceLineNo">289</span> // explicit that scans normally don't use the block cache.<a name="line.289"></a> |
| <span class="sourceLineNo">290</span> s.setCacheBlocks(false);<a name="line.290"></a> |
| <span class="sourceLineNo">291</span><a name="line.291"></a> |
| <span class="sourceLineNo">292</span> // Open up the scanner and close it automatically when done.<a name="line.292"></a> |
| <span class="sourceLineNo">293</span> try (ResultScanner rs = t.getScanner(s)) {<a name="line.293"></a> |
| <span class="sourceLineNo">294</span><a name="line.294"></a> |
| <span class="sourceLineNo">295</span> // Now go through rows.<a name="line.295"></a> |
| <span class="sourceLineNo">296</span> for (Result r : rs) {<a name="line.296"></a> |
| <span class="sourceLineNo">297</span> // Keep track of things size to simulate doing some real work.<a name="line.297"></a> |
| <span class="sourceLineNo">298</span> result += r.getRow().length;<a name="line.298"></a> |
| <span class="sourceLineNo">299</span> toRead -= 1;<a name="line.299"></a> |
| <span class="sourceLineNo">300</span><a name="line.300"></a> |
| <span class="sourceLineNo">301</span> // Most online applications won't be<a name="line.301"></a> |
| <span class="sourceLineNo">302</span> // reading the entire table so this break<a name="line.302"></a> |
| <span class="sourceLineNo">303</span> // simulates small to medium size scans,<a name="line.303"></a> |
| <span class="sourceLineNo">304</span> // without needing to know an end row.<a name="line.304"></a> |
| <span class="sourceLineNo">305</span> if (toRead <= 0) {<a name="line.305"></a> |
| <span class="sourceLineNo">306</span> break;<a name="line.306"></a> |
| <span class="sourceLineNo">307</span> }<a name="line.307"></a> |
| <span class="sourceLineNo">308</span> }<a name="line.308"></a> |
| <span class="sourceLineNo">309</span> }<a name="line.309"></a> |
| <span class="sourceLineNo">310</span> }<a name="line.310"></a> |
| <span class="sourceLineNo">311</span> return result > 0;<a name="line.311"></a> |
| <span class="sourceLineNo">312</span> }<a name="line.312"></a> |
| <span class="sourceLineNo">313</span> }<a name="line.313"></a> |
| <span class="sourceLineNo">314</span><a name="line.314"></a> |
| <span class="sourceLineNo">315</span> public static void main(String[] args) throws Exception {<a name="line.315"></a> |
| <span class="sourceLineNo">316</span> ToolRunner.run(new MultiThreadedClientExample(), args);<a name="line.316"></a> |
| <span class="sourceLineNo">317</span> }<a name="line.317"></a> |
| <span class="sourceLineNo">318</span>}<a name="line.318"></a> |
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| </pre> |
| </div> |
| </body> |
| </html> |
