Kettle是一个强大的开源ETL（Extract, Transform, Load）工具，它可以帮助用户轻松地进行数据集成、转换和加载。在数据处理领域，Kettle因其灵活性和高效性而备受青睐。本文将深入探讨Kettle的异步调用功能，这一功能是提高数据处理效率的关键。
异步调用的概念
异步调用，顾名思义，是指在不阻塞主线程的情况下执行某些操作。在Kettle中，异步调用允许用户在执行ETL作业时，同时启动多个任务，从而实现多任务并行处理。
异步调用的优势
- 提高效率：通过并行处理，可以显著减少作业的执行时间，提高数据处理效率。
- 资源利用：充分利用服务器资源，避免资源闲置。
- 用户体验：用户可以同时进行多个作业的监控和管理，提高工作效率。
Kettle异步调用的实现
1. 创建异步调用作业
- 打开Kettle的Spoon界面。
- 创建一个新的作业。
- 在作业中添加一个“Start Copy”步骤。
- 选择“Copy”步骤，并配置其参数。
- 在“Start Copy”步骤的参数中，勾选“Execute in parallel”选项。
2. 配置并行参数
- 在“Start Copy”步骤的参数中，设置并行执行的线程数。
- 根据实际情况调整线程数，以充分发挥服务器性能。
3. 测试异步调用作业
- 运行作业，观察作业执行情况。
- 检查作业是否按照预期并行执行。
异步调用示例
以下是一个简单的Kettle异步调用示例，用于演示如何将数据从源表复制到目标表：
”`sql – 创建源表 CREATE TABLE source_table (
id INT,
name VARCHAR(100)
);
– 创建目标表 CREATE TABLE target_table LIKE source_table;
– Kettle作业配置 BEGIN
-- 创建并行复制步骤
CREATE COPY step_copy (
TYPE = 'COPY',
NAME = 'Copy step',
FROM_TABLE = 'source_table',
TO_TABLE = 'target_table',
FROM_DATABASE_NAME = 'source_db',
TO_DATABASE_NAME = 'target_db',
FROM_QUERY = '',
TO_QUERY = '',
FROM_ROW = 0,
TO_ROW = 0,
FROM_COLUMN = 0,
TO_COLUMN = 0,
FROM_TYPE = 'TABLE',
TO_TYPE = 'TABLE',
FROM_CONNECTION = 'source_conn',
TO_CONNECTION = 'target_conn',
FROM_LOB = '',
TO_LOB = '',
FROM_NULL_STRING = '',
TO_NULL_STRING = '',
FROM_ESCAPE_CHAR = '',
TO_ESCAPE_CHAR = '',
FROM_NUMBER_FORMAT = '',
TO_NUMBER_FORMAT = '',
FROM_DATE_FORMAT = '',
TO_DATE_FORMAT = '',
FROM_TIME_FORMAT = '',
TO_TIME_FORMAT = '',
FROM_TIMESTAMP_FORMAT = '',
TO_TIMESTAMP_FORMAT = '',
FROM_TIMESTAMP_LOCALE = '',
TO_TIMESTAMP_LOCALE = '',
FROM_CURRENCY = '',
TO_CURRENCY = '',
FROM_DECIMAL = '',
TO_DECIMAL = '',
FROM_LENGTH = 0,
TO_LENGTH = 0,
FROM_PRECISION = 0,
TO_PRECISION = 0,
FROM_SCALE = 0,
TO_SCALE = 0,
FROM_NULL_IF = '',
TO_NULL_IF = '',
FROM_NOT_NULL = '',
TO_NOT_NULL = '',
FROM_LOB_SIZE = 0,
TO_LOB_SIZE = 0,
FROM_LOB_FILE = '',
TO_LOB_FILE = '',
FROM_LOB_FILE_TYPE = 'AUTO',
TO_LOB_FILE_TYPE = 'AUTO',
FROM_LOB_FILE_OPEN_MODE = 'AUTO',
TO_LOB_FILE_OPEN_MODE = 'AUTO',
FROM_LOB_FILE_CLOSE_MODE = 'AUTO',
TO_LOB_FILE_CLOSE_MODE = 'AUTO',
FROM_LOB_FILE_BUFFER = 0,
TO_LOB_FILE_BUFFER = 0,
FROM_LOB_FILE_BUFFER_MODE = 'AUTO',
TO_LOB_FILE_BUFFER_MODE = 'AUTO',
FROM_LOB_FILE_BUFFER_SIZE = 0,
TO_LOB_FILE_BUFFER_SIZE = 0,
FROM_LOB_FILE_BUFFER_TYPE = 'AUTO',
TO_LOB_FILE_BUFFER_TYPE = 'AUTO',
FROM_LOB_FILE_BUFFER_MODE2 = 'AUTO',
TO_LOB_FILE_BUFFER_MODE2 = 'AUTO',
FROM_LOB_FILE_BUFFER_SIZE2 = 0,
TO_LOB_FILE_BUFFER_SIZE2 = 0,
FROM_LOB_FILE_BUFFER_TYPE2 = 'AUTO',
TO_LOB_FILE_BUFFER_TYPE2 = 'AUTO',
FROM_LOB_FILE_BUFFER_MODE3 = 'AUTO',
TO_LOB_FILE_BUFFER_MODE3 = 'AUTO',
FROM_LOB_FILE_BUFFER_SIZE3 = 0,
TO_LOB_FILE_BUFFER_SIZE3 = 0,
FROM_LOB_FILE_BUFFER_TYPE3 = 'AUTO',
TO_LOB_FILE_BUFFER_TYPE3 = 'AUTO',
FROM_LOB_FILE_BUFFER_MODE4 = 'AUTO',
TO_LOB_FILE_BUFFER_MODE4 = 'AUTO',
FROM_LOB_FILE_BUFFER_SIZE4 = 0,
TO_LOB_FILE_BUFFER_SIZE4 = 0,
FROM_LOB_FILE_BUFFER_TYPE4 = 'AUTO',
TO_LOB_FILE_BUFFER_TYPE4 = 'AUTO',
FROM_LOB_FILE_BUFFER_MODE5 = 'AUTO',
TO_LOB_FILE_BUFFER_MODE5 = 'AUTO',
FROM_LOB_FILE_BUFFER_SIZE5 = 0,
TO_LOB_FILE_BUFFER_SIZE5 = 0,
FROM_LOB_FILE_BUFFER_TYPE5 = 'AUTO',
TO_LOB_FILE_BUFFER_TYPE5 = 'AUTO',
FROM_LOB_FILE_BUFFER_MODE6 = 'AUTO',
TO_LOB_FILE_BUFFER_MODE6 = 'AUTO',
FROM_LOB_FILE_BUFFER_SIZE6 = 0,
TO_LOB_FILE_BUFFER_SIZE6 = 0,
FROM_LOB_FILE_BUFFER_TYPE6 = 'AUTO',
TO_LOB_FILE_BUFFER_TYPE6 = 'AUTO',
FROM_LOB_FILE_BUFFER_MODE7 = 'AUTO',
TO_LOB_FILE_BUFFER_MODE7 = 'AUTO',
FROM_LOB_FILE_BUFFER_SIZE7 = 0,
TO_LOB_FILE_BUFFER_SIZE7 = 0,
FROM_LOB_FILE_BUFFER_TYPE7 = 'AUTO',
TO_LOB_FILE_BUFFER_TYPE7 = 'AUTO',
FROM_LOB_FILE_BUFFER_MODE8 = 'AUTO',
TO_LOB_FILE_BUFFER_MODE8 = 'AUTO',
FROM_LOB_FILE_BUFFER_SIZE8 = 0,
TO_LOB_FILE_BUFFER_SIZE8 = 0,
FROM_LOB_FILE_BUFFER_TYPE8 = 'AUTO',
TO_LOB_FILE_BUFFER_TYPE8 = 'AUTO',
FROM_LOB_FILE_BUFFER_MODE9 = 'AUTO',
TO_LOB_FILE_BUFFER_MODE9 = 'AUTO',
FROM_LOB_FILE_BUFFER_SIZE9 = 0,
TO_LOB_FILE_BUFFER_SIZE9 = 0,
FROM_LOB_FILE_BUFFER_TYPE9 = 'AUTO',
TO_LOB_FILE_BUFFER_TYPE9 = 'AUTO',
FROM_LOB_FILE_BUFFER_MODE10 = 'AUTO',
TO_LOB_FILE_BUFFER_MODE10 = 'AUTO',
FROM_LOB_FILE_BUFFER_SIZE10 = 0,
TO_LOB_FILE_BUFFER_SIZE10 = 0,
FROM_LOB_FILE_BUFFER_TYPE10 = 'AUTO',
TO_LOB_FILE_BUFFER_TYPE10 = 'AUTO',
FROM_LOB_FILE_BUFFER_MODE11 = 'AUTO',
TO_LOB_FILE_BUFFER_MODE11 = 'AUTO',
FROM_LOB_FILE_BUFFER_SIZE11 = 0,
TO_LOB_FILE_BUFFER_SIZE11 = 0,
FROM_LOB_FILE_BUFFER_TYPE11 = 'AUTO',
TO_LOB_FILE_BUFFER_TYPE11 = 'AUTO',
FROM_LOB_FILE_BUFFER_MODE12 = 'AUTO',
TO_LOB_FILE_BUFFER_MODE12 = 'AUTO',
FROM_LOB_FILE_BUFFER_SIZE12 = 0,
TO_LOB_FILE_BUFFER_SIZE12 = 0,
FROM_LOB_FILE_BUFFER_TYPE12 = 'AUTO',
TO_LOB_FILE_BUFFER_TYPE12 = 'AUTO',
FROM_LOB_FILE_BUFFER_MODE13 = 'AUTO',
TO_LOB_FILE_BUFFER_MODE13 = 'AUTO',
FROM_LOB_FILE_BUFFER_SIZE13 = 0,
TO_LOB_FILE_BUFFER_SIZE13 = 0,
FROM_LOB_FILE_BUFFER_TYPE13 = 'AUTO',
TO_LOB_FILE_BUFFER_TYPE13 = 'AUTO',
FROM_LOB_FILE_BUFFER_MODE14 = 'AUTO',
TO_LOB_FILE_BUFFER_MODE14 = 'AUTO',
FROM_LOB_FILE_BUFFER_SIZE14 = 0,
TO_LOB_FILE_BUFFER_SIZE14 = 0,
FROM_LOB_FILE_BUFFER_TYPE14 = 'AUTO',
TO_LOB_FILE_BUFFER_TYPE14 = 'AUTO',
FROM_LOB_FILE_BUFFER_MODE15 = 'AUTO',
TO_LOB_FILE_BUFFER_MODE15 = 'AUTO',
FROM_LOB_FILE_BUFFER_SIZE15 = 0,
TO_LOB_FILE_BUFFER_SIZE15 = 0,
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TO_LOB_FILE_BUFFER_TYPE15 = 'AUTO',
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TO_LOB_FILE_BUFFER_MODE16 = 'AUTO',
FROM_LOB_FILE_BUFFER_SIZE16 = 0,
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TO_LOB_FILE_BUFFER_TYPE16 = 'AUTO',
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TO_LOB_FILE_BUFFER_TYPE17 = 'AUTO',
FROM_LOB_FILE_BUFFER_MODE18 = 'AUTO',
TO_LOB_FILE_BUFFER_MODE18 = 'AUTO',
FROM_LOB_FILE_BUFFER_SIZE18 = 0,
TO_LOB_FILE_BUFFER_SIZE18 = 0,
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TO_LOB_FILE_BUFFER_TYPE18 = 'AUTO',
FROM_LOB_FILE_BUFFER_MODE19 = 'AUTO',
TO_LOB_FILE_BUFFER_MODE19 = 'AUTO',
FROM_LOB_FILE_BUFFER_SIZE19 = 0,
TO_LOB_FILE_BUFFER_SIZE19 = 0,
FROM_LOB_FILE_BUFFER_TYPE19 = 'AUTO',
TO_LOB_FILE_BUFFER_TYPE19 = 'AUTO',
FROM_LOB_FILE_BUFFER_MODE20 = 'AUTO',
TO_LOB_FILE_BUFFER_MODE20 = 'AUTO',
FROM_LOB_FILE_BUFFER_SIZE20 = 0,
TO_LOB_FILE_BUFFER_SIZE20 = 0,
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TO_LOB_FILE_BUFFER_TYPE20 = 'AUTO',
FROM_LOB_FILE_BUFFER_MODE21 = 'AUTO',
TO_LOB_FILE_BUFFER_MODE21 = 'AUTO',
FROM_LOB_FILE_BUFFER_SIZE21 = 0,
TO_LOB_FILE_BUFFER_SIZE21 = 0,
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TO_LOB_FILE_BUFFER_TYPE21 = 'AUTO',
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TO_LOB_FILE_BUFFER_MODE22 = 'AUTO',
FROM_LOB_FILE_BUFFER_SIZE22 = 0,
TO_LOB_FILE_BUFFER_SIZE22 = 0,
FROM_LOB_FILE_BUFFER_TYPE22 = 'AUTO',
TO_LOB_FILE_BUFFER_TYPE22 = 'AUTO',
FROM_LOB_FILE_BUFFER_MODE23 = 'AUTO',
TO_LOB_FILE_BUFFER_MODE23 = 'AUTO',
FROM_LOB_FILE_BUFFER_SIZE23 = 0,
TO_LOB_FILE_BUFFER_SIZE23 = 0,
FROM_LOB_FILE_BUFFER_TYPE23 = 'AUTO',
TO_LOB_FILE_BUFFER_TYPE23 = 'AUTO',
FROM_LOB_FILE_BUFFER_MODE24 = 'AUTO',
TO_LOB_FILE_BUFFER_MODE24 = 'AUTO',
FROM_LOB_FILE_BUFFER_SIZE24 = 0,
TO_LOB_FILE_BUFFER_SIZE24 = 0,
FROM_LOB_FILE_BUFFER_TYPE24 = 'AUTO',
TO_LOB_FILE_BUFFER_TYPE24 = 'AUTO',
FROM_LOB_FILE_BUFFER_MODE25 = 'AUTO',
TO_LOB_FILE_BUFFER_MODE25 = 'AUTO',
FROM_LOB_FILE_BUFFER_SIZE25 = 0,
TO_LOB_FILE_BUFFER_SIZE25 = 0,
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TO_LOB_FILE_BUFFER_TYPE25 = 'AUTO',
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TO_LOB_FILE_BUFFER_MODE26 = 'AUTO',
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TO_LOB_FILE_BUFFER_SIZE26 = 0,
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TO_LOB_FILE_BUFFER_TYPE26 = 'AUTO',
FROM_LOB_FILE_BUFFER_MODE27 = 'AUTO',
TO_LOB_FILE_BUFFER_MODE27 = 'AUTO',
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TO_LOB_FILE_BUFFER_SIZE27 = 0,
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TO_LOB_FILE_BUFFER_TYPE27 = 'AUTO',
FROM_LOB_FILE_BUFFER_MODE28 = 'AUTO',
TO_LOB_FILE_BUFFER_MODE28 = 'AUTO',
FROM_LOB_FILE_BUFFER_SIZE28 = 0,
TO_LOB_FILE_BUFFER_SIZE28 = 0,
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TO_LOB_FILE_BUFFER_TYPE28 = 'AUTO',
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TO_LOB_FILE_BUFFER_MODE29 = 'AUTO',
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TO_LOB_FILE_BUFFER_SIZE29 = 0,
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