Step 설명
이 Step은 구분자로 필드가 구분된 파일에서 데이터를 읽습니다. Text File Input step보다 전체적인 기능은 적지만 몇가지 특별한 기능을 가지고 있습니다:
- NIO -- 파일을 읽을 때 네이티브 시스템 콜을 사용하여 성능이 뛰어납니다 그너아 현재는 로컬 파일만 읽을 수 있고, VFS는 지원하지 않습니다.
- Parallel running -- If you configure this step to run in multiple copies or in clustered mode, and you enable parallel running, each copy will read a separate block of a single file allowing you to distribute the file reading to several threads or even several slave nodes in a clustered transformation.
- Lazy conversion -- If you will be reading many fields from the file and many of those fields will not be manipulate, but merely passed through the transformation to land in some other text file or a database, lazy conversion can prevent Kettle from performing unnecessary work on those fields such as converting them into objects such as strings, dates, or numbers.
옵션
The table below describes the options available for the CSV Input step:
Option |
Description |
---|---|
Step name |
Name of the step.
|
Filename |
Specify the name of the CSV file to read from. |
Delimiter |
Specify the file delimiter character used in the target file. |
Enclosure |
Specify the enclosure character used in the target file. |
NIO buffer size |
This is the size of the read buffer. It represents the amount of bytes that is read in one time from disk. |
Lazy conversion |
The lazy conversion algorithm will try to avoid unnecessary data type conversions and can result in a significant performance improvements if this is possible. The typical example that comes to mind is reading from a text file and writing back to a text file. |
Header row present? |
Enable this option if the target file contains a header row containing column names. |
Add filename to result |
Adds the CSV filename(s) read to the result of this transformation. A unique list is being kept in memory that can be used in the next job entry in a job, for example in another transformation. |
The row number field name (optional) |
The name of the Integer field that will contain the row number in the output of this step. |
Running in parallel? |
Check this box if you will have multiple instances of this step running (step copies) and if you want each instance to read a separate part of the CSV file(s).
|
File Encoding |
Specify the encoding of the file being read. |
Fields Table |
This table contains an ordered list of fields to be read from the target file. |
Preview button |
Click to preview the data coming from the target file. |
Get Fields button |
Click to return a list of fields from the target file based on the current settings (i.e. Delimiter, Enclosure, etc.). All fields identified will be added to the Fields Table. |