> ## Documentation Index
> Fetch the complete documentation index at: https://clickhouse.com/docs/llms.txt
> Use this file to discover all available pages before exploring further.

> 使用 NiFi 数据管道将数据流式写入 ClickHouse

# 将 Apache NiFi 连接到 ClickHouse

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<a href="https://nifi.apache.org/" target="_blank">Apache NiFi</a> 是一款开源工作流管理软件，用于自动化不同软件系统之间的数据流转。它支持创建 ETL 数据管道，并内置了 300 多种数据处理器。本分步教程将介绍如何将 Apache NiFi 连接到 ClickHouse，使其既可作为源端，也可作为目标端，并加载一个样本数据集。

<Steps>
  <Step title="准备连接信息" id="1-gather-your-connection-details">
    要通过 HTTP(S) 连接到 ClickHouse，你需要以下信息：

    | Parameter(s)              | Description                                |
    | ------------------------- | ------------------------------------------ |
    | `HOST` and `PORT`         | 通常，使用 TLS 时端口为 8443；不使用 TLS 时端口为 8123。     |
    | `DATABASE NAME`           | 默认情况下，存在一个名为 `default` 的数据库。请使用你要连接的数据库名称。 |
    | `USERNAME` and `PASSWORD` | 默认情况下，用户名为 `default`。请根据你的使用场景使用相应的用户名。    |

    你的 ClickHouse Cloud 服务的连接信息可在 ClickHouse Cloud 控制台中查看。
    选择一个服务，然后点击 **Connect**：

    <div className="ch-image-md">
      <Frame>
        <img src="https://mintcdn.com/private-7c7dfe99/CFFsa2agBPbviR4r/images/_snippets/cloud-connect-button.webp?fit=max&auto=format&n=CFFsa2agBPbviR4r&q=85&s=ec0a298a33ca841e947fa5e8bae47362" alt="ClickHouse Cloud 服务连接按钮" width="998" height="932" data-path="images/_snippets/cloud-connect-button.webp" />
      </Frame>
    </div>

    选择 **HTTPS**。连接信息会显示在示例 `curl` 命令中。

    <div className="ch-image-md">
      <Frame>
        <img src="https://mintcdn.com/private-7c7dfe99/CFFsa2agBPbviR4r/images/_snippets/connection-details-https.webp?fit=max&auto=format&n=CFFsa2agBPbviR4r&q=85&s=cb0fbd98aa2b5b7ca484c9f53395ee07" alt="ClickHouse Cloud HTTPS 连接信息" width="1320" height="1184" data-path="images/_snippets/connection-details-https.webp" />
      </Frame>
    </div>

    如果你使用的是自管理 ClickHouse，则连接信息由你的 ClickHouse 管理员配置。
  </Step>

  <Step title="下载并运行 Apache NiFi" id="2-download-and-run-apache-nifi">
    对于全新部署，请从 [https://nifi.apache.org/download.html](https://nifi.apache.org/download.html) 下载二进制程序，然后运行 `./bin/nifi.sh start` 启动服务
  </Step>

  <Step title="下载 ClickHouse JDBC 驱动" id="3-download-the-clickhouse-jdbc-driver">
    1. 访问 GitHub 上的 <a href="https://github.com/ClickHouse/clickhouse-java/releases" target="_blank">ClickHouse JDBC 驱动发布页面</a>，查找最新的 JDBC 发布版本
    2. 在该发布版本页面中，点击 "Show all xx assets"，然后找到文件名中包含关键字 "shaded" 或 "all" 的 JAR 文件，例如 `clickhouse-jdbc-0.5.0-all.jar`
    3. 将该 JAR 文件放在 Apache NiFi 可访问的文件夹中，并记下其绝对路径
  </Step>

  <Step title={<>添加 <code>DBCPConnectionPool</code> Controller Service 并配置其属性</>} id="4-add-dbcpconnectionpool-controller-service-and-configure-its-properties">
    1. 要在 Apache NiFi 中配置 Controller Service，请点击“齿轮”按钮，进入 NiFi Flow Configuration 页面

           <Image img="https://mintcdn.com/private-7c7dfe99/pIetLsS_hOGHqoPJ/images/integrations/data-ingestion/etl-tools/nifi_01.webp?fit=max&auto=format&n=pIetLsS_hOGHqoPJ&q=85&s=3ecb50806baacf0177cdde10d0bea34c" size="sm" border alt="突出显示齿轮按钮的 NiFi Flow Configuration 页面" width="564" height="409" data-path="images/integrations/data-ingestion/etl-tools/nifi_01.webp" />

    2. 选择 Controller Services 选项卡，然后点击右上角的 `+` 按钮，添加新的 Controller Service

           <Image img="https://mintcdn.com/private-7c7dfe99/pIetLsS_hOGHqoPJ/images/integrations/data-ingestion/etl-tools/nifi_02.webp?fit=max&auto=format&n=pIetLsS_hOGHqoPJ&q=85&s=e49f17a3ccf81855ddf6f33ae71f8b2d" size="lg" border alt="突出显示添加按钮的 Controller Services 选项卡" width="1999" height="636" data-path="images/integrations/data-ingestion/etl-tools/nifi_02.webp" />

    3. 搜索 `DBCPConnectionPool`，然后点击“Add”按钮

           <Image img="https://mintcdn.com/private-7c7dfe99/pIetLsS_hOGHqoPJ/images/integrations/data-ingestion/etl-tools/nifi_03.webp?fit=max&auto=format&n=pIetLsS_hOGHqoPJ&q=85&s=a214a72eb65b893a71426c349c6851a4" size="lg" border alt="突出显示 DBCPConnectionPool 的 Controller Service 选择对话框" width="1999" height="1287" data-path="images/integrations/data-ingestion/etl-tools/nifi_03.webp" />

    4. 新添加的 `DBCPConnectionPool` 默认处于 Invalid 状态。点击“齿轮”按钮开始配置

           <Image img="https://mintcdn.com/private-7c7dfe99/pIetLsS_hOGHqoPJ/images/integrations/data-ingestion/etl-tools/nifi_04.webp?fit=max&auto=format&n=pIetLsS_hOGHqoPJ&q=85&s=5bc4d67491b1e5958664762878c41a87" size="lg" border alt="显示处于 Invalid 状态的 DBCPConnectionPool 且突出显示齿轮按钮的 Controller Services 列表" width="1893" height="607" data-path="images/integrations/data-ingestion/etl-tools/nifi_04.webp" />

    5. 在“Properties”部分中，输入以下值

    | Property                   | 值                                                                                        | 备注                              |
    | -------------------------- | ---------------------------------------------------------------------------------------- | ------------------------------- |
    | Database Connection URL    | jdbc[https://HOSTNAME:8443/default?ssl=true](https://HOSTNAME:8443/default?ssl=true)true | 相应替换 connection URL 中的 HOSTNAME |
    | Database Driver Class Name | com.clickhouse.jdbc.ClickHouseDriver                                                     |                                 |
    | Database Driver Locations  | /etc/nifi/nifi-X.XX.X/lib/clickhouse-jdbc-0.X.X-patchXX-shaded.jar                       | ClickHouse JDBC 驱动 JAR 文件的绝对路径  |
    | Database User              | default                                                                                  | ClickHouse 用户名                  |
    | Password                   | password                                                                                 | ClickHouse 密码                   |

    6. 在 Settings 部分中，将 Controller Service 的名称改为“ClickHouse JDBC”，以便后续识别

           <Image img="https://mintcdn.com/private-7c7dfe99/pIetLsS_hOGHqoPJ/images/integrations/data-ingestion/etl-tools/nifi_05.webp?fit=max&auto=format&n=pIetLsS_hOGHqoPJ&q=85&s=869cce96c0ee8ccd527695c8dea21af7" size="lg" border alt="显示已填写属性的 DBCPConnectionPool 配置对话框" width="1586" height="1184" data-path="images/integrations/data-ingestion/etl-tools/nifi_05.webp" />

    7. 点击“lightning”按钮，然后点击“Enable”按钮，启用 `DBCPConnectionPool` Controller Service

           <Image img="https://mintcdn.com/private-7c7dfe99/pIetLsS_hOGHqoPJ/images/integrations/data-ingestion/etl-tools/nifi_06.webp?fit=max&auto=format&n=pIetLsS_hOGHqoPJ&q=85&s=2460399dc3113d995786c373f7df4d37" size="lg" border alt="突出显示 lightning 按钮的 Controller Services 列表" width="2878" height="812" data-path="images/integrations/data-ingestion/etl-tools/nifi_06.webp" />

           <br />

           <Image img="https://mintcdn.com/private-7c7dfe99/pIetLsS_hOGHqoPJ/images/integrations/data-ingestion/etl-tools/nifi_07.webp?fit=max&auto=format&n=pIetLsS_hOGHqoPJ&q=85&s=485f45409ead4ff9cfb316e8ee2bc8d9" size="lg" border alt="启用 Controller Service 的确认对话框" width="1586" height="1172" data-path="images/integrations/data-ingestion/etl-tools/nifi_07.webp" />

    8. 检查 Controller Services 选项卡，确认该 Controller Service 已启用

           <Image img="https://mintcdn.com/private-7c7dfe99/pIetLsS_hOGHqoPJ/images/integrations/data-ingestion/etl-tools/nifi_08.webp?fit=max&auto=format&n=pIetLsS_hOGHqoPJ&q=85&s=b7d9e1ce84d3bbd46d913e940847a610" size="lg" border alt="显示已启用 ClickHouse JDBC 服务的 Controller Services 列表" width="1999" height="636" data-path="images/integrations/data-ingestion/etl-tools/nifi_08.webp" />
  </Step>

  <Step title={<>使用 <code>ExecuteSQL</code> 处理器从表中读取数据</>} id="5-read-from-a-table-using-the-executesql-processor">
    1. 添加 `ExecuteSQL` 处理器，以及相应的上游和下游处理器

           <Image img="https://mintcdn.com/private-7c7dfe99/pIetLsS_hOGHqoPJ/images/integrations/data-ingestion/etl-tools/nifi_09.webp?fit=max&auto=format&n=pIetLsS_hOGHqoPJ&q=85&s=abf11db5bb1dc248a233669a23aef33e" size="md" border alt="NiFi 画布，显示工作流中的 ExecuteSQL 处理器" width="768" height="316" data-path="images/integrations/data-ingestion/etl-tools/nifi_09.webp" />

    2. 在 `ExecuteSQL` 处理器的 "Properties" 部分中，填写以下值

       | Property                            | Value                         | Remark                                |
       | ----------------------------------- | ----------------------------- | ------------------------------------- |
       | Database Connection Pooling Service | ClickHouse JDBC               | 选择为 ClickHouse 配置的 Controller Service |
       | SQL select query                    | SELECT \* FROM system.metrics | 在此输入查询                                |

    3. 启动 `ExecuteSQL` 处理器

           <Image img="https://mintcdn.com/private-7c7dfe99/pIetLsS_hOGHqoPJ/images/integrations/data-ingestion/etl-tools/nifi_10.webp?fit=max&auto=format&n=pIetLsS_hOGHqoPJ&q=85&s=81d02e73ee6ca1d543015bc0667eb442" size="lg" border alt="已填写属性的 ExecuteSQL 处理器配置" width="858" height="220" data-path="images/integrations/data-ingestion/etl-tools/nifi_10.webp" />

    4. 要确认查询已成功处理，请检查输出队列中的一个 `FlowFile`

           <Image img="https://mintcdn.com/private-7c7dfe99/pIetLsS_hOGHqoPJ/images/integrations/data-ingestion/etl-tools/nifi_11.webp?fit=max&auto=format&n=pIetLsS_hOGHqoPJ&q=85&s=270caae3211e7b81b50d1e309aba8606" size="lg" border alt="队列列表对话框，显示可供检查的 FlowFile" width="1956" height="794" data-path="images/integrations/data-ingestion/etl-tools/nifi_11.webp" />

    5. 将视图切换为 "formatted"，查看输出 `FlowFile` 的结果

           <Image img="https://mintcdn.com/private-7c7dfe99/pIetLsS_hOGHqoPJ/images/integrations/data-ingestion/etl-tools/nifi_12.webp?fit=max&auto=format&n=pIetLsS_hOGHqoPJ&q=85&s=1dc1c90d3bb71ab84465021653fddadf" size="lg" border alt="FlowFile 内容查看器，以 formatted 视图显示查询结果" width="1762" height="1500" data-path="images/integrations/data-ingestion/etl-tools/nifi_12.webp" />
  </Step>

  <Step title={<>使用 <code>MergeRecord</code> 和 <code>PutDatabaseRecord</code> 处理器向表中写入数据</>} id="6-write-to-a-table-using-mergerecord-and-putdatabaserecord-processor">
    1. 要在一次插入中写入多行，首先需要将多条记录合并为一条记录。这可以通过 `MergeRecord` 处理器实现

    2. 在 `MergeRecord` 处理器的 "Properties" 部分中，填入以下值

       | Property                  | Value               | Remark                                               |
       | ------------------------- | ------------------- | ---------------------------------------------------- |
       | Record Reader             | `JSONTreeReader`    | 选择合适的记录读取器                                           |
       | Record Writer             | `JSONReadSetWriter` | 选择合适的记录写入器                                           |
       | Minimum Number of Records | 1000                | 将此值设大一些，以便至少合并这么多行来组成一条记录。默认值为 1 行                   |
       | Maximum Number of Records | 10000               | 将此值设为高于 "Minimum Number of Records" 的数字。默认值为 1,000 行 |

    3. 要确认多条记录已合并为一条记录，请检查 `MergeRecord` 处理器的输入和输出。注意，输出是一个包含多条输入记录的数组

       输入

           <Image img="https://mintcdn.com/private-7c7dfe99/pIetLsS_hOGHqoPJ/images/integrations/data-ingestion/etl-tools/nifi_13.webp?fit=max&auto=format&n=pIetLsS_hOGHqoPJ&q=85&s=2ccc4198a02b0b3b7402ee79e5ae12c8" size="sm" border alt="显示单条记录的 MergeRecord 处理器输入" width="624" height="306" data-path="images/integrations/data-ingestion/etl-tools/nifi_13.webp" />

       输出

           <Image img="https://mintcdn.com/private-7c7dfe99/pIetLsS_hOGHqoPJ/images/integrations/data-ingestion/etl-tools/nifi_14.webp?fit=max&auto=format&n=pIetLsS_hOGHqoPJ&q=85&s=0b02a554dceeb6c594fd800d04dcfb89" size="sm" border alt="显示合并后记录数组的 MergeRecord 处理器输出" width="707" height="501" data-path="images/integrations/data-ingestion/etl-tools/nifi_14.webp" />

    4. 在 `PutDatabaseRecord` 处理器的 "Properties" 部分中，填入以下值

       | Property                            | Value            | Remark                                                                   |
       | ----------------------------------- | ---------------- | ------------------------------------------------------------------------ |
       | Record Reader                       | `JSONTreeReader` | 选择合适的记录读取器                                                               |
       | Database Type                       | Generic          | 保持默认值                                                                    |
       | Statement Type                      | INSERT           |                                                                          |
       | Database Connection Pooling Service | ClickHouse JDBC  | 选择 ClickHouse 控制器服务                                                      |
       | Table Name                          | tbl              | 在此输入你的表名                                                                 |
       | Translate Field Names               | false            | 设为 "false"，这样插入的字段名必须与列名一致                                               |
       | Maximum Batch Size                  | 1000             | 每次 insert 的最大行数。该值不应低于 `MergeRecord` 处理器中 "Minimum Number of Records" 的值 |

    5. 要确认每次 insert 都包含多行，请检查表中的行数是否每次至少按 `MergeRecord` 中定义的 "Minimum Number of Records" 的值递增。

           <Image img="https://mintcdn.com/private-7c7dfe99/pIetLsS_hOGHqoPJ/images/integrations/data-ingestion/etl-tools/nifi_15.webp?fit=max&auto=format&n=pIetLsS_hOGHqoPJ&q=85&s=36b01a981712543038b0c3f5d2f06679" size="sm" border alt="显示目标端表中行数的查询结果" width="828" height="1306" data-path="images/integrations/data-ingestion/etl-tools/nifi_15.webp" />

    6. 恭喜——你已成功使用 Apache NiFi 将数据加载到 ClickHouse 中！
  </Step>
</Steps>
