This documentation is for an unreleased version of Apache Flink. We recommend you use the latest stable version.

Print SQL Connector #

Sink

The Print connector allows for writing every row to the standard output or standard error stream.

It is designed for:

Four possible format options:

Print	Condition1	Condition2
PRINT_IDENTIFIER:taskId> output	PRINT_IDENTIFIER provided	parallelism > 1
PRINT_IDENTIFIER> output	PRINT_IDENTIFIER provided	parallelism == 1
taskId> output	no PRINT_IDENTIFIER provided	parallelism > 1
output	no PRINT_IDENTIFIER provided	parallelism == 1

The output string format is “$row_kind(f0,f1,f2…)”, row_kind is the short string of RowKind, example is: “+I(1,1)”.

The Print connector is built-in.

Attention Print sinks print records in runtime tasks, you need to observe the task log.

How to create a Print table #

CREATE TABLE print_table (
  f0 INT,
  f1 INT,
  f2 STRING,
  f3 DOUBLE
) WITH (
  'connector' = 'print'
);

Alternatively, it may be based on an existing schema using the LIKE Clause.

CREATE TABLE print_table WITH ('connector' = 'print')
LIKE source_table (EXCLUDING ALL)

Option	Required	Default	Type	Description
connector	required	(none)	String	Specify what connector to use, here should be 'print'.
print-identifier	optional	(none)	String	Message that identify print and is prefixed to the output of the value.
standard-error	optional	false	Boolean	True, if the format should print to standard error instead of standard out.
sink.parallelism	optional	(none)	Integer	Defines the parallelism of the Print sink operator. By default, the parallelism is determined by the framework using the same parallelism of the upstream chained operator.