import{_ as o,r as p,o as c,c as l,a as i,d as s,e as n,b as t,f as e}from"./app-acb943bf.js";const r={},d=e('<h1 id="c-原生接口" tabindex="-1"><a class="header-anchor" href="#c-原生接口" aria-hidden="true">#</a> C# 原生接口</h1><h2 id="依赖" tabindex="-1"><a class="header-anchor" href="#依赖" aria-hidden="true">#</a> 依赖</h2><ul><li>.NET SDK &gt;= 5.0 或 .NET Framework 4.x</li><li>Thrift &gt;= 0.14.1</li><li>NLog &gt;= 4.7.9</li></ul><h2 id="安装" tabindex="-1"><a class="header-anchor" href="#安装" aria-hidden="true">#</a> 安装</h2><p>您可以使用 NuGet Package Manager, .NET CLI等工具来安装，以 .NET CLI为例</p>',5),u={href:"http://xn--2rqw7v40f05fc0bu89avfc.NET",target:"_blank",rel:"noopener noreferrer"},k=s("div",{class:"language-text line-numbers-mode","data-ext":"text"},[s("pre",{class:"language-text"},[s("code",null,`dotnet add package Apache.IoTDB
`)]),s("div",{class:"line-numbers","aria-hidden":"true"},[s("div",{class:"line-number"})])],-1),h={href:"http://xn--2rqw7v40f05fc0bu89avfc.NET",target:"_blank",rel:"noopener noreferrer"},m=e(`<div class="language-bash line-numbers-mode" data-ext="sh"><pre class="language-bash"><code>dotnet <span class="token function">add</span> package Apache.IoTDB.framework
</code></pre><div class="line-numbers" aria-hidden="true"><div class="line-number"></div></div></div><p>如果您想安装更早版本的客户端，只需要指定版本即可</p><div class="language-bash line-numbers-mode" data-ext="sh"><pre class="language-bash"><code><span class="token comment"># 安装0.12.1.2版本的客户端</span>
dotnet <span class="token function">add</span> package Apache.IoTDB <span class="token parameter variable">--version</span> <span class="token number">0.12</span>.1.2
</code></pre><div class="line-numbers" aria-hidden="true"><div class="line-number"></div><div class="line-number"></div></div></div><h2 id="基本接口说明" tabindex="-1"><a class="header-anchor" href="#基本接口说明" aria-hidden="true">#</a> 基本接口说明</h2><p>Session接口在语义上和其他语言客户端相同</p><div class="language-csharp line-numbers-mode" data-ext="cs"><pre class="language-csharp"><code><span class="token comment">// 参数定义</span>
<span class="token class-name"><span class="token keyword">string</span></span> host <span class="token operator">=</span> <span class="token string">&quot;localhost&quot;</span><span class="token punctuation">;</span>
<span class="token class-name"><span class="token keyword">int</span></span> port <span class="token operator">=</span> <span class="token number">6667</span><span class="token punctuation">;</span>
<span class="token class-name"><span class="token keyword">int</span></span> pool_size <span class="token operator">=</span> <span class="token number">2</span><span class="token punctuation">;</span>

<span class="token comment">// 初始化session</span>
<span class="token class-name"><span class="token keyword">var</span></span> session_pool <span class="token operator">=</span> <span class="token keyword">new</span> <span class="token constructor-invocation class-name">SessionPool</span><span class="token punctuation">(</span>host<span class="token punctuation">,</span> port<span class="token punctuation">,</span> pool_size<span class="token punctuation">)</span><span class="token punctuation">;</span>

<span class="token comment">// 开启session</span>
<span class="token keyword">await</span> session_pool<span class="token punctuation">.</span><span class="token function">Open</span><span class="token punctuation">(</span><span class="token boolean">false</span><span class="token punctuation">)</span><span class="token punctuation">;</span>

<span class="token comment">// 创建时间序列</span>
<span class="token keyword">await</span> session_pool<span class="token punctuation">.</span><span class="token function">CreateTimeSeries</span><span class="token punctuation">(</span><span class="token string">&quot;root.test_group.test_device.ts1&quot;</span><span class="token punctuation">,</span> TSDataType<span class="token punctuation">.</span>TEXT<span class="token punctuation">,</span> TSEncoding<span class="token punctuation">.</span>PLAIN<span class="token punctuation">,</span> Compressor<span class="token punctuation">.</span>UNCOMPRESSED<span class="token punctuation">)</span><span class="token punctuation">;</span>
<span class="token keyword">await</span> session_pool<span class="token punctuation">.</span><span class="token function">CreateTimeSeries</span><span class="token punctuation">(</span><span class="token string">&quot;root.test_group.test_device.ts2&quot;</span><span class="token punctuation">,</span> TSDataType<span class="token punctuation">.</span>BOOLEAN<span class="token punctuation">,</span> TSEncoding<span class="token punctuation">.</span>PLAIN<span class="token punctuation">,</span> Compressor<span class="token punctuation">.</span>UNCOMPRESSED<span class="token punctuation">)</span><span class="token punctuation">;</span>
<span class="token keyword">await</span> session_pool<span class="token punctuation">.</span><span class="token function">CreateTimeSeries</span><span class="token punctuation">(</span><span class="token string">&quot;root.test_group.test_device.ts3&quot;</span><span class="token punctuation">,</span> TSDataType<span class="token punctuation">.</span>INT32<span class="token punctuation">,</span> TSEncoding<span class="token punctuation">.</span>PLAIN<span class="token punctuation">,</span> Compressor<span class="token punctuation">.</span>UNCOMPRESSED<span class="token punctuation">)</span><span class="token punctuation">;</span>

<span class="token comment">// 插入record</span>
<span class="token class-name"><span class="token keyword">var</span></span> measures <span class="token operator">=</span> <span class="token keyword">new</span> <span class="token constructor-invocation class-name">List<span class="token punctuation">&lt;</span><span class="token keyword">string</span><span class="token punctuation">&gt;</span></span><span class="token punctuation">{</span><span class="token string">&quot;ts1&quot;</span><span class="token punctuation">,</span> <span class="token string">&quot;ts2&quot;</span><span class="token punctuation">,</span> <span class="token string">&quot;ts3&quot;</span><span class="token punctuation">}</span><span class="token punctuation">;</span>
<span class="token class-name"><span class="token keyword">var</span></span> values <span class="token operator">=</span> <span class="token keyword">new</span> <span class="token constructor-invocation class-name">List<span class="token punctuation">&lt;</span><span class="token keyword">object</span><span class="token punctuation">&gt;</span></span> <span class="token punctuation">{</span> <span class="token string">&quot;test_text&quot;</span><span class="token punctuation">,</span> <span class="token boolean">true</span><span class="token punctuation">,</span> <span class="token punctuation">(</span><span class="token keyword">int</span><span class="token punctuation">)</span><span class="token number">123</span> <span class="token punctuation">}</span><span class="token punctuation">;</span>
<span class="token class-name"><span class="token keyword">var</span></span> timestamp <span class="token operator">=</span> <span class="token number">1</span><span class="token punctuation">;</span>
<span class="token class-name"><span class="token keyword">var</span></span> rowRecord <span class="token operator">=</span> <span class="token keyword">new</span> <span class="token constructor-invocation class-name">RowRecord</span><span class="token punctuation">(</span>timestamp<span class="token punctuation">,</span> values<span class="token punctuation">,</span> measures<span class="token punctuation">)</span><span class="token punctuation">;</span>
<span class="token keyword">await</span> session_pool<span class="token punctuation">.</span><span class="token function">InsertRecordAsync</span><span class="token punctuation">(</span><span class="token string">&quot;root.test_group.test_device&quot;</span><span class="token punctuation">,</span> rowRecord<span class="token punctuation">)</span><span class="token punctuation">;</span>

<span class="token comment">// 插入Tablet</span>
<span class="token class-name"><span class="token keyword">var</span></span> timestamp_lst <span class="token operator">=</span> <span class="token keyword">new</span> <span class="token constructor-invocation class-name">List<span class="token punctuation">&lt;</span><span class="token keyword">long</span><span class="token punctuation">&gt;</span></span><span class="token punctuation">{</span> timestamp <span class="token operator">+</span> <span class="token number">1</span> <span class="token punctuation">}</span><span class="token punctuation">;</span>
<span class="token class-name"><span class="token keyword">var</span></span> value_lst <span class="token operator">=</span> <span class="token keyword">new</span> <span class="token constructor-invocation class-name">List<span class="token punctuation">&lt;</span><span class="token keyword">object</span><span class="token punctuation">&gt;</span></span> <span class="token punctuation">{</span><span class="token keyword">new</span><span class="token punctuation">(</span><span class="token punctuation">)</span> <span class="token punctuation">{</span><span class="token string">&quot;iotdb&quot;</span><span class="token punctuation">,</span> <span class="token boolean">true</span><span class="token punctuation">,</span> <span class="token punctuation">(</span><span class="token keyword">int</span><span class="token punctuation">)</span> <span class="token number">12</span><span class="token punctuation">}</span><span class="token punctuation">}</span><span class="token punctuation">;</span>
<span class="token class-name"><span class="token keyword">var</span></span> tablet <span class="token operator">=</span> <span class="token keyword">new</span> <span class="token constructor-invocation class-name">Tablet</span><span class="token punctuation">(</span><span class="token string">&quot;root.test_group.test_device&quot;</span><span class="token punctuation">,</span> measures<span class="token punctuation">,</span> value_lst<span class="token punctuation">,</span> timestamp_ls<span class="token punctuation">)</span><span class="token punctuation">;</span>
<span class="token keyword">await</span> session_pool<span class="token punctuation">.</span><span class="token function">InsertTabletAsync</span><span class="token punctuation">(</span>tablet<span class="token punctuation">)</span><span class="token punctuation">;</span>

<span class="token comment">// 关闭Session</span>
<span class="token keyword">await</span> session_pool<span class="token punctuation">.</span><span class="token function">Close</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">;</span>
</code></pre><div class="line-numbers" aria-hidden="true"><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div></div></div><h2 id="row-record" tabindex="-1"><a class="header-anchor" href="#row-record" aria-hidden="true">#</a> <strong>Row Record</strong></h2><ul><li>对<strong>IoTDB</strong>中的<code>record</code>数据进行封装和抽象。</li><li>示例：</li></ul><table><thead><tr><th>timestamp</th><th>status</th><th>temperature</th></tr></thead><tbody><tr><td>1</td><td>0</td><td>20</td></tr></tbody></table><ul><li>构造方法：</li></ul><div class="language-csharp line-numbers-mode" data-ext="cs"><pre class="language-csharp"><code><span class="token class-name"><span class="token keyword">var</span></span> rowRecord <span class="token operator">=</span> 
  <span class="token keyword">new</span> <span class="token constructor-invocation class-name">RowRecord</span><span class="token punctuation">(</span><span class="token class-name"><span class="token keyword">long</span></span> timestamps<span class="token punctuation">,</span> <span class="token class-name">List<span class="token punctuation">&lt;</span><span class="token keyword">object</span><span class="token punctuation">&gt;</span></span> values<span class="token punctuation">,</span> <span class="token class-name">List<span class="token punctuation">&lt;</span><span class="token keyword">string</span><span class="token punctuation">&gt;</span></span> measurements<span class="token punctuation">)</span><span class="token punctuation">;</span>
</code></pre><div class="line-numbers" aria-hidden="true"><div class="line-number"></div><div class="line-number"></div></div></div><h3 id="tablet" tabindex="-1"><a class="header-anchor" href="#tablet" aria-hidden="true">#</a> <strong>Tablet</strong></h3><ul><li>一种类似于表格的数据结构，包含一个设备的若干行非空数据块。</li><li>示例：</li></ul><table><thead><tr><th>time</th><th>status</th><th>temperature</th></tr></thead><tbody><tr><td>1</td><td>0</td><td>20</td></tr><tr><td>2</td><td>0</td><td>20</td></tr><tr><td>3</td><td>3</td><td>21</td></tr></tbody></table><ul><li>构造方法：</li></ul><div class="language-csharp line-numbers-mode" data-ext="cs"><pre class="language-csharp"><code><span class="token class-name"><span class="token keyword">var</span></span> tablet <span class="token operator">=</span> 
  <span class="token function">Tablet</span><span class="token punctuation">(</span><span class="token class-name"><span class="token keyword">string</span></span> deviceId<span class="token punctuation">,</span>  <span class="token class-name">List<span class="token punctuation">&lt;</span><span class="token keyword">string</span><span class="token punctuation">&gt;</span></span> measurements<span class="token punctuation">,</span> <span class="token class-name">List<span class="token punctuation">&lt;</span>List<span class="token punctuation">&lt;</span><span class="token keyword">object</span><span class="token punctuation">&gt;</span><span class="token punctuation">&gt;</span></span> values<span class="token punctuation">,</span> <span class="token class-name">List<span class="token punctuation">&lt;</span><span class="token keyword">long</span><span class="token punctuation">&gt;</span></span> timestamps<span class="token punctuation">)</span><span class="token punctuation">;</span>
</code></pre><div class="line-numbers" aria-hidden="true"><div class="line-number"></div><div class="line-number"></div></div></div><h2 id="api" tabindex="-1"><a class="header-anchor" href="#api" aria-hidden="true">#</a> <strong>API</strong></h2><h3 id="基础接口" tabindex="-1"><a class="header-anchor" href="#基础接口" aria-hidden="true">#</a> <strong>基础接口</strong></h3><table><thead><tr><th>api name</th><th>parameters</th><th>notes</th><th>use example</th></tr></thead><tbody><tr><td>Open</td><td>bool</td><td>open session</td><td>session_pool.Open(false)</td></tr><tr><td>Close</td><td>null</td><td>close session</td><td>session_pool.Close()</td></tr><tr><td>IsOpen</td><td>null</td><td>check if session is open</td><td>session_pool.IsOpen()</td></tr><tr><td>OpenDebugMode</td><td>LoggingConfiguration=null</td><td>open debug mode</td><td>session_pool.OpenDebugMode()</td></tr><tr><td>CloseDebugMode</td><td>null</td><td>close debug mode</td><td>session_pool.CloseDebugMode()</td></tr><tr><td>SetTimeZone</td><td>string</td><td>set time zone</td><td>session_pool.GetTimeZone()</td></tr><tr><td>GetTimeZone</td><td>null</td><td>get time zone</td><td>session_pool.GetTimeZone()</td></tr></tbody></table><h3 id="record相关接口" tabindex="-1"><a class="header-anchor" href="#record相关接口" aria-hidden="true">#</a> <strong>Record相关接口</strong></h3><table><thead><tr><th>api name</th><th>parameters</th><th>notes</th><th>use example</th></tr></thead><tbody><tr><td>InsertRecordAsync</td><td>string, RowRecord</td><td>insert single record</td><td>session_pool.InsertRecordAsync(&quot;root.97209_TEST_CSHARP_CLIENT_GROUP.TEST_CSHARP_CLIENT_DEVICE&quot;, new RowRecord(1, values, measures));</td></tr><tr><td>InsertRecordsAsync</td><td>List&lt;string&gt;, List&lt;RowRecord&gt;</td><td>insert records</td><td>session_pool.InsertRecordsAsync(device_id, rowRecords)</td></tr><tr><td>InsertRecordsOfOneDeviceAsync</td><td>string, List&lt;RowRecord&gt;</td><td>insert records of one device</td><td>session_pool.InsertRecordsOfOneDeviceAsync(device_id, rowRecords)</td></tr><tr><td>InsertRecordsOfOneDeviceSortedAsync</td><td>string, List&lt;RowRecord&gt;</td><td>insert sorted records of one device</td><td>InsertRecordsOfOneDeviceSortedAsync(deviceId, sortedRowRecords);</td></tr><tr><td>TestInsertRecordAsync</td><td>string, RowRecord</td><td>test insert record</td><td>session_pool.TestInsertRecordAsync(&quot;root.97209_TEST_CSHARP_CLIENT_GROUP.TEST_CSHARP_CLIENT_DEVICE&quot;, rowRecord)</td></tr><tr><td>TestInsertRecordsAsync</td><td>List&lt;string&gt;, List&lt;RowRecord&gt;</td><td>test insert record</td><td>session_pool.TestInsertRecordsAsync(device_id, rowRecords)</td></tr></tbody></table><h3 id="tablet相关接口" tabindex="-1"><a class="header-anchor" href="#tablet相关接口" aria-hidden="true">#</a> <strong>Tablet相关接口</strong></h3><table><thead><tr><th>api name</th><th>parameters</th><th>notes</th><th>use example</th></tr></thead><tbody><tr><td>InsertTabletAsync</td><td>Tablet</td><td>insert single tablet</td><td>session_pool.InsertTabletAsync(tablet)</td></tr><tr><td>InsertTabletsAsync</td><td>List&lt;Tablet&gt;</td><td>insert tablets</td><td>session_pool.InsertTabletsAsync(tablets)</td></tr><tr><td>TestInsertTabletAsync</td><td>Tablet</td><td>test insert tablet</td><td>session_pool.TestInsertTabletAsync(tablet)</td></tr><tr><td>TestInsertTabletsAsync</td><td>List&lt;Tablet&gt;</td><td>test insert tablets</td><td>session_pool.TestInsertTabletsAsync(tablets)</td></tr></tbody></table><h3 id="sql语句接口" tabindex="-1"><a class="header-anchor" href="#sql语句接口" aria-hidden="true">#</a> <strong>SQL语句接口</strong></h3><table><thead><tr><th>api name</th><th>parameters</th><th>notes</th><th>use example</th></tr></thead><tbody><tr><td>ExecuteQueryStatementAsync</td><td>string</td><td>execute sql query statement</td><td>session_pool.ExecuteQueryStatementAsync(&quot;select * from root.97209_TEST_CSHARP_CLIENT_GROUP.TEST_CSHARP_CLIENT_DEVICE where time&lt;15&quot;);</td></tr><tr><td>ExecuteNonQueryStatementAsync</td><td>string</td><td>execute sql nonquery statement</td><td>session_pool.ExecuteNonQueryStatementAsync( &quot;create timeseries root.97209_TEST_CSHARP_CLIENT_GROUP.TEST_CSHARP_CLIENT_DEVICE.status with datatype=BOOLEAN,encoding=PLAIN&quot;)</td></tr></tbody></table><h3 id="数据表接口" tabindex="-1"><a class="header-anchor" href="#数据表接口" aria-hidden="true">#</a> 数据表接口</h3><table><thead><tr><th>api name</th><th>parameters</th><th>notes</th><th>use example</th></tr></thead><tbody><tr><td>SetStorageGroup</td><td>string</td><td>set storage group</td><td>session_pool.SetStorageGroup(&quot;root.97209_TEST_CSHARP_CLIENT_GROUP_01&quot;)</td></tr><tr><td>CreateTimeSeries</td><td>string, TSDataType, TSEncoding, Compressor</td><td>create time series</td><td>session_pool.InsertTabletsAsync(tablets)</td></tr><tr><td>DeleteStorageGroupAsync</td><td>string</td><td>delete single storage group</td><td>session_pool.DeleteStorageGroupAsync(&quot;root.97209_TEST_CSHARP_CLIENT_GROUP_01&quot;)</td></tr><tr><td>DeleteStorageGroupsAsync</td><td>List&lt;string&gt;</td><td>delete storage group</td><td>session_pool.DeleteStorageGroupAsync(&quot;root.97209_TEST_CSHARP_CLIENT_GROUP&quot;)</td></tr><tr><td>CreateMultiTimeSeriesAsync</td><td>List&lt;string&gt;, List&lt;TSDataType&gt; , List&lt;TSEncoding&gt; , List&lt;Compressor&gt;</td><td>create multi time series</td><td>session_pool.CreateMultiTimeSeriesAsync(ts_path_lst, data_type_lst, encoding_lst, compressor_lst);</td></tr><tr><td>DeleteTimeSeriesAsync</td><td>List&lt;string&gt;</td><td>delete time series</td><td></td></tr><tr><td>DeleteTimeSeriesAsync</td><td>string</td><td>delete time series</td><td></td></tr><tr><td>DeleteDataAsync</td><td>List&lt;string&gt;, long, long</td><td>delete data</td><td>session_pool.DeleteDataAsync(ts_path_lst, 2, 3)</td></tr></tbody></table><h3 id="辅助接口" tabindex="-1"><a class="header-anchor" href="#辅助接口" aria-hidden="true">#</a> <strong>辅助接口</strong></h3><table><thead><tr><th>api name</th><th>parameters</th><th>notes</th><th>use example</th></tr></thead><tbody><tr><td>CheckTimeSeriesExistsAsync</td><td>string</td><td>check if time series exists</td><td>session_pool.CheckTimeSeriesExistsAsync(time series)</td></tr></tbody></table>`,29),b={href:"https://github.com/apache/iotdb-client-csharp/tree/main/samples/Apache.IoTDB.Samples",target:"_blank",rel:"noopener noreferrer"},v=e(`<h2 id="连接池" tabindex="-1"><a class="header-anchor" href="#连接池" aria-hidden="true">#</a> 连接池</h2><p>为了实现并发客户端请求，我们提供了针对原生接口的连接池(<code>SessionPool</code>)，由于<code>SessionPool</code>本身为<code>Session</code>的超集，当<code>SessionPool</code>的<code>pool_size</code>参数设置为1时，退化为原来的<code>Session</code></p><p>我们使用<code>ConcurrentQueue</code>数据结构封装了一个客户端队列，以维护与服务端的多个连接，当调用<code>Open()</code>接口时，会在该队列中创建指定个数的客户端，同时通过<code>System.Threading.Monitor</code>类实现对队列的同步访问。</p><p>当请求发生时，会尝试从连接池中寻找一个空闲的客户端连接，如果没有空闲连接，那么程序将需要等待直到有空闲连接</p><p>当一个连接被用完后，他会自动返回池中等待下次被使用</p><h2 id="bytebuffer" tabindex="-1"><a class="header-anchor" href="#bytebuffer" aria-hidden="true">#</a> ByteBuffer</h2><p>在传入RPC接口参数时，需要对Record和Tablet两种数据结构进行序列化，我们主要通过封装的ByteBuffer类实现</p><p>在封装字节序列的基础上，我们进行了内存预申请与内存倍增的优化，减少了序列化过程中内存的申请和释放，在一个拥有20000行的Tablet上进行序列化测试时，速度比起原生的数组动态增长具有<strong>35倍的性能加速</strong></p><h3 id="实现介绍" tabindex="-1"><a class="header-anchor" href="#实现介绍" aria-hidden="true">#</a> 实现介绍</h3><p>在进行<code>RowRecords</code>以及<code>Tablet</code>的插入时，我们需要对多行RowRecord和Tablet进行序列化以进行发送。客户端中的序列化实现主要依赖于ByteBuffer完成。接下来我们介绍ByteBuffer的实现细节。本文包含如下几点内容:</p><ul><li>序列化的协议</li><li>C#与Java的大小端的差异</li><li>ByteBuffer内存倍增算法</li></ul><h3 id="序列化协议" tabindex="-1"><a class="header-anchor" href="#序列化协议" aria-hidden="true">#</a> 序列化协议</h3><p>客户端向IoTDB服务器发送的序列化数据总体应该包含两个信息。</p><ul><li>数据类型</li><li>数据本身</li></ul><p>其中对于<code>字符串</code>的序列化时，我们需要再加入字符串的长度信息。即一个字符串的序列化完整结果为:</p><pre><code>[类型][长度][数据内容]
</code></pre><p>接下来我们分别介绍<code>RowRecord</code>、<code>Tablet</code>的序列化方式</p><h4 id="rowrecord" tabindex="-1"><a class="header-anchor" href="#rowrecord" aria-hidden="true">#</a> RowRecord</h4><p>我们对RowRecord进行序列化时，<code>伪代码</code>如下:</p><div class="language-csharp line-numbers-mode" data-ext="cs"><pre class="language-csharp"><code><span class="token keyword">public</span> <span class="token return-type class-name"><span class="token keyword">byte</span><span class="token punctuation">[</span><span class="token punctuation">]</span></span> <span class="token function">value_to_bytes</span><span class="token punctuation">(</span><span class="token class-name">List<span class="token punctuation">&lt;</span>TSDataType<span class="token punctuation">&gt;</span></span> data_types<span class="token punctuation">,</span> <span class="token class-name">List<span class="token punctuation">&lt;</span><span class="token keyword">string</span><span class="token punctuation">&gt;</span></span> values<span class="token punctuation">)</span><span class="token punctuation">{</span>
    <span class="token class-name">ByteBuffer</span> buffer <span class="token operator">=</span> <span class="token keyword">new</span> <span class="token constructor-invocation class-name">ByteBuffer</span><span class="token punctuation">(</span>values<span class="token punctuation">.</span>Count<span class="token punctuation">)</span><span class="token punctuation">;</span>
    <span class="token keyword">for</span><span class="token punctuation">(</span><span class="token class-name"><span class="token keyword">int</span></span> i <span class="token operator">=</span> <span class="token number">0</span><span class="token punctuation">;</span>i <span class="token operator">&lt;</span> data_types<span class="token punctuation">.</span><span class="token function">Count</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">;</span> i<span class="token operator">++</span><span class="token punctuation">)</span><span class="token punctuation">{</span>
        buffer<span class="token punctuation">.</span><span class="token function">add_type</span><span class="token punctuation">(</span><span class="token punctuation">(</span>data_types<span class="token punctuation">[</span>i<span class="token punctuation">]</span><span class="token punctuation">)</span><span class="token punctuation">;</span>
        buffer<span class="token punctuation">.</span><span class="token function">add_val</span><span class="token punctuation">(</span>values<span class="token punctuation">[</span>i<span class="token punctuation">]</span><span class="token punctuation">)</span><span class="token punctuation">;</span>
    <span class="token punctuation">}</span>
<span class="token punctuation">}</span>
</code></pre><div class="line-numbers" aria-hidden="true"><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div></div></div><p>对于其序列化的结果格式如下:</p><pre><code>[数据类型1][数据1][数据类型2][数据2]...[数据类型N][数据N]
</code></pre><p>其中数据类型为自定义的<code>Enum</code>变量，分别如下:</p><div class="language-csharp line-numbers-mode" data-ext="cs"><pre class="language-csharp"><code><span class="token keyword">public</span> <span class="token keyword">enum</span> <span class="token class-name">TSDataType</span><span class="token punctuation">{</span>BOOLEAN<span class="token punctuation">,</span> INT32<span class="token punctuation">,</span> INT64<span class="token punctuation">,</span> FLOAT<span class="token punctuation">,</span> DOUBLE<span class="token punctuation">,</span> TEXT<span class="token punctuation">,</span> NONE<span class="token punctuation">}</span><span class="token punctuation">;</span>
</code></pre><div class="line-numbers" aria-hidden="true"><div class="line-number"></div></div></div><h4 id="tablet序列化" tabindex="-1"><a class="header-anchor" href="#tablet序列化" aria-hidden="true">#</a> Tablet序列化</h4><p>使用<code>Tabelt</code>进行数据插入时有如下限制:</p><pre><code>限制：Tablet中数据不能有空值
</code></pre><p>由于向 <code>IoTDB</code>服务器发送<code>Tablet</code>数据插入请求时会携带<code>行数</code>， <code>列数</code>, <code>列数据类型</code>，所以<code>Tabelt</code>序列化时我们不需要加入数据类型信息。<code>Tablet</code>是<code>按照列进行序列化</code>，这是因为后端可以通过行数得知出当前列的元素个数，同时根据列类型来对数据进行解析。</p><h3 id="csharp与java序列化数据时的大小端差异" tabindex="-1"><a class="header-anchor" href="#csharp与java序列化数据时的大小端差异" aria-hidden="true">#</a> CSharp与Java序列化数据时的大小端差异</h3><p>由于Java序列化默认大端协议，而CSharp序列化默认得到小端序列。所以我们在CSharp中序列化数据之后，需要对数据进行反转这样后端才可以正常解析。同时当我们从后端获取到序列化的结果时(如<code>SessionDataset</code>)，我们也需要对获得的数据进行反转以解析内容。这其中特例便是字符串的序列化，CSharp中对字符串的序列化结果为大端序，所以序列化字符串或者接收到字符串序列化结果时，不需要反转序列结果。</p><h3 id="bytebuffer内存倍增法" tabindex="-1"><a class="header-anchor" href="#bytebuffer内存倍增法" aria-hidden="true">#</a> ByteBuffer内存倍增法</h3><p>拥有数万行的Tablet的序列化结果可能有上百兆，为了能够高效的实现大<code>Tablet</code>的序列化，我们对ByteBuffer使用<code>内存倍增法</code>的策略来减少序列化过程中对于内存的申请和释放。即当当前的buffer的长度不足以放下序列化结果时，我们将当前buffer的内存<code>至少</code>扩增2倍。这极大的减少了内存的申请释放次数，加速了大Tablet的序列化速度。</p><div class="language-csharp line-numbers-mode" data-ext="cs"><pre class="language-csharp"><code><span class="token keyword">private</span> <span class="token return-type class-name"><span class="token keyword">void</span></span> <span class="token function">extend_buffer</span><span class="token punctuation">(</span><span class="token class-name"><span class="token keyword">int</span></span> space_need<span class="token punctuation">)</span><span class="token punctuation">{</span>
        <span class="token keyword">if</span><span class="token punctuation">(</span>write_pos <span class="token operator">+</span> space_need <span class="token operator">&gt;=</span> total_length<span class="token punctuation">)</span><span class="token punctuation">{</span>
            total_length <span class="token operator">=</span> <span class="token function">max</span><span class="token punctuation">(</span>space_need<span class="token punctuation">,</span> total_length<span class="token punctuation">)</span><span class="token punctuation">;</span>
            <span class="token class-name"><span class="token keyword">byte</span><span class="token punctuation">[</span><span class="token punctuation">]</span></span> new_buffer <span class="token operator">=</span> <span class="token keyword">new</span> <span class="token constructor-invocation class-name"><span class="token keyword">byte</span></span><span class="token punctuation">[</span>total_length <span class="token operator">*</span> <span class="token number">2</span><span class="token punctuation">]</span><span class="token punctuation">;</span>
            buffer<span class="token punctuation">.</span><span class="token function">CopyTo</span><span class="token punctuation">(</span>new_buffer<span class="token punctuation">,</span> <span class="token number">0</span><span class="token punctuation">)</span><span class="token punctuation">;</span>
            buffer <span class="token operator">=</span> new_buffer<span class="token punctuation">;</span>
            total_length <span class="token operator">=</span> <span class="token number">2</span> <span class="token operator">*</span> total_length<span class="token punctuation">;</span>
        <span class="token punctuation">}</span>
<span class="token punctuation">}</span>
</code></pre><div class="line-numbers" aria-hidden="true"><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div></div></div><p>同时在序列化<code>Tablet</code>时，我们首先根据Tablet的<code>行数</code>，<code>列数</code>以及每一列的数据类型估计当前<code>Tablet</code>序列化结果所需要的内存大小，并在初始化时进行内存的申请。这进一步的减少了内存的申请释放频率。</p><p>通过上述的策略，我们在一个有<code>20000</code>行的Tablet上进行测试时，序列化速度相比Naive数组长度动态生长实现算法具有约35倍的性能加速。</p><h2 id="异常重连" tabindex="-1"><a class="header-anchor" href="#异常重连" aria-hidden="true">#</a> 异常重连</h2><p>当服务端发生异常或者宕机重启时，客户端中原来通过<code>Open()</code>产生的的session会失效，抛出<code>TException</code>异常</p><p>为了避免这一情况的发生，我们对大部分的接口进行了增强，一旦出现连接问题，就会尝试重新调用<code>Open()</code>接口并创建新的Session，并尝试重新发送对应的请求</p>`,38);function g(y,_){const a=p("ExternalLinkIcon");return c(),l("div",null,[i(`

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