Function

The Print connector is used to print output data to the error file or TaskManager file, making it easier for you to view the result in code debugging.

Prerequisites

None

Precautions

The Print result table supports the following output formats:

Print	Condition 1	Condition 2
Identifier:Task ID> Output data	A print identifier prefix must be provided. That is, you must specify print-identifier in the WITH parameter when creating the Print result table.	parallelism > 1
Identifier> Output data	A print identifier prefix must be provided. That is, you must specify print-identifier in the WITH parameter when creating the Print result table.	parallelism == 1
Task ID> Output data	A print identifier prefix is not needed. That is, you do not specify print-identifier in the WITH parameter when creating the Print result table.	parallelism > 1
Output data	A print identifier prefix is not needed. That is, you do not specify print-identifier in the WITH parameter when creating the Print result table.	parallelism == 1

When creating a Flink OpenSource SQL job, you need to set Flink Version to 1.12 on the Running Parameters tab of the job editing page, select Save Job Log, and set the OBS bucket for saving job logs.

Syntax

create table printSink (
  attr_name attr_type 
  (',' attr_name attr_type) * 
  (',' PRIMARY KEY (attr_name,...) NOT ENFORCED)
) with (
  'connector' = 'print',
  'print-identifier' = '',
  'standard-error' = ''
);

Parameters

**Table 1** Parameter description
Parameter	Mandatory	Default Value	Data Type	Description
connector	Yes	None	String	Connector to be used. Set this parameter to print.
print-identifier	No	None	String	Message that identifies print and is prefixed to the output of the value.
standard-error	No	false	Boolean	The value can be only true or false. The default value is false. If the value is true, data is output to the error file of the TaskManager. If the value is false, data is output to the out file of the TaskManager.

Example

Create a Flink OpenSource SQL job. Run the following script to generate random data through the DataGen table and output the data to the Print result table.

When you create a job, set Flink Version to 1.12 on the Running Parameters tab. Select Save Job Log, and specify the OBS bucket for saving job logs.

create table dataGenSOurce(
  user_id string,
  amount int
) with (
  'connector' = 'datagen',
  'rows-per-second' = '1', --Generate a piece of data per second.
  'fields.user_id.kind' = 'random', --Specify a random generator for the user_id field.
  'fields.user_id.length' = '3' --Limit the length of user_id to 3.
);

create table printSink(
  user_id string,
  amount int
) with (
  'connector' = 'print'
);

insert into printSink select * from dataGenSOurce;

After the job is submitted, the job status changes to Running. You can perform the following operations of either method to view the output result: