Help Center/ MapReduce Service/ Component Operation Guide (LTS)/ Using Loader/ Operator Help/ Using Macro Definitions in Configuration Items
Updated on 2022-11-18 GMT+08:00
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Using Macro Definitions in Configuration Items

When creating or editing Loader jobs, users can use macro definitions during parameter configuration. Then the parameters can be automatically changed to corresponding macro values when a job is implemented.

  • The macro definitions take effect in the job only.
  • Macro definitions can be imported and exported together with an import or export job. If a job uses macro definitions, the exported job includes the macro definitions. Macro definitions are imported by default when a job is imported.
  • For details about the dateformat definition of the first parameter in the time macro dataformat, see java.text.SimpleDateFormat.java. The restrictions of the target system must be followed. For example, HDFS/OBS directories do not support special characters.

Macro Definitions of Loader

At present, Loader supports the following time macro definitions by default:

Table 1 Common macro definitions of Loader

Name

Result After the Replacement

Description

@{dateformat("yyyy-MM-dd")}@

2016-05-17

Indicates the current date.

@{dateformat("yyyy-MM-dd HH:mm:ss")}@

2016-05-17 16:50:00

Indicates current date and time

@{timestamp()}@

1463476137557

Indicates milliseconds since 1970.

@{dateformat("yyyy-MM-dd HH:mm:ss",-7,DAYS)}@

2016-05-10 16:50:00

Indicates the latest seven days (the present time minus seven days).

The second parameter supports addition and subtraction.

The third parameter is a time unit for calculation. According to definitions in the java.util.concurrent.TimeUnit.java, time units include DAYS, HOURS, MINUTES, and SECONDS.

In the following scenarios, parameters can be configured by using macro definitions.

  • Specifying a data directory that is named by the current date

    The parameter is set to /user/data/inputdate_@{dateformat("yyyy-MM-dd")} @.

  • Querying data in the latest seven days by using SQL 
    select * from table where time between '@{dateformat("yyyy-MM-dd HH:mm:ss",-7,DAYS)}@' and '@{dateformat("yyyy-MM-dd HH:mm:ss")}@'
  • Specifying a table that is named by the current date

    The parameter is set to table_@{dateformat("yyyy-MM-dd")} @parmvalue.

Parent topic: Operator Help