To HDFS

If the destination link of a job is one of them listed in Link to HDFS, configure the destination job parameters based on Table 1.

Table 1 Parameter description

Parameter

Description

Example Value

Write Directory

HDFS directory to which data will be written.

This parameter can be configured as a macro variable of date and time and a path name can contain multiple macro variables. When the macro variable of date and time works with a scheduled job, the incremental data can be synchronized periodically.

/user/output

File Format

Format in which data is written. The options are as follows:

  • CSV: Data is written in CSV format, which is used for migrating data tables to files.

  • Binary: Files will be transferred directly. CDM writes the files without changing their format. This setting is suitable for file migration.

If data is migrated between file-related data sources, such as FTP, SFTP, HDFS, and OBS, the value of File Format must the same as the source file format.

CSV

Duplicate File Processing Method

Files with the same name and size are identified as duplicate files. If there are duplicate files during data writing, the following methods are available:

  • Replace

  • Skip

  • Stop job

Stop job

Compression Format

File compression format after data writing. The following compression formats are supported:

  • None: The files are not compressed.

  • DEFLATE: The files are compressed in DEFLATE format.

  • gzip: The files are compressed in gzip format.

  • bzip2: The files are compressed in bzip2 format.

  • LZ4: The files are compressed in LZ4 format.

  • Snappy: The files are compressed in snappy format.

Snappy

Line Separator

Lind feed character in a file. By default, the system automatically identifies \n, \r, and \r\n. This parameter is not used when File Format is set to Binary.

\n

Field Delimiter

Field delimiter in the file. This parameter is not used when File Format is set to Binary.

,

Use Quote Character

This parameter is displayed only when File Format is CSV. It is used when database tables are migrated to file systems.

If you set this parameter to Yes and a field in the source data table contains a field delimiter or line separator, CDM uses double quotation marks (") as the quote character to quote the field content as a whole to prevent a field delimiter from dividing a field into two fields, or a line separator from dividing a field into different lines. For example, if the hello,world field in the database is quoted, it will be exported to the CSV file as a whole.

No

Use First Row as Header

When a table is migrated to a CSV file, CDM does not migrate the heading line of the table by default. If you set this parameter to Yes, CDM writes the heading line of the table to the file.

No

Write to Temporary File

Whether to write the binary file to a .tmp file first. After the migration is successful, run the rename or move command at the migration destination to restore the file.

No

Job Success Marker File

Whether to generate a marker file with a custom name in the destination directory after a job is executed successfully. If you do not specify a file name, this function is disabled by default.

finish.txt

Customize Hierarchical Directory

Users can customize the directory hierarchy of files. Example: [Table name]/[Year]/[Month]/[Day]/[Data file name]. csv

-

Hierarchical Directory

Used to specify the directory level of a file, with time macro supported (the time format is yyyy/MM/dd). If this parameter is left blank, the directory does not have a hierarchical structure. Example: ${dateformat(yyyy/MM/dd, -1, DAY)}

-

Encryption

This parameter is displayed only when File Format is set to Binary.

Whether to encrypt the uploaded data. The options are as follows:

  • None: Data is written without encryption.

  • AES-256-GCM: The AES 256-bit encryption algorithm is used to encrypt data. Currently, only the AES-256-GCM (NoPadding) encryption algorithm is supported. This parameter is used for encryption at the migration destination and decryption at the migration source.

AES-256-GCM

DEK

This parameter is displayed only when Encryption is set to AES-256-GCM. The key consists of 64 hexadecimal numbers.

Remember the key configured here because the decryption key must be the same as that configured here. If the encryption and decryption keys are inconsistent, the system does not report an exception, but the decrypted data is incorrect.

DD0AE00DFECD78BF051BCFDA25BD4E320DB0A7AC75A1F3FC3D3C56A457DCDC1B

IV

This parameter is displayed only when Encryption is set to AES-256-GCM. The initialization vector consists of 32 hexadecimal numbers.

Remember the initialization vector configured here because the initialization vector used for decryption must be the same as that configured here. If the initialization vectors are inconsistent, the system does not report an exception, but the decrypted data is incorrect.

5C91687BA886EDCD12ACBC3FF19A3C3F

Note

HDFS supports the UTF-8 encoding only. Retain the default value UTF-8.