ALTER ETL - Lindorm - Alibaba Cloud Documentation Center

The ALTER ETL statement modifies ETL tasks with a RUNNING status.

Engine and version

ALTER ETL applies only to the stream engine. Version 3.1.8 or later is required.

Note

You can view and update the minor version in the console.

Syntax

alter_etl_statement ::= ALTER ETL etl_name
                        [WITH etl_properties]
                        AS INSERT INTO [[catalog_name.]db_name.]table_name column_list 
                        select_statement

etl_properties       ::= '(' property_definition (',' property_definition)* ')'
property_definition  ::= property_name '=' property_value  
column_list          ::= '(' column_name (',' column_name)* ')'

Usage notes

ETL name (etl_name)

Required. Specifies the ETL task to modify.

ETL properties (etl_properties)

Use the WITH keyword to add the following ETL properties:

Important

Enclose property names in backticks (`) and property values in single quotation marks ('). For example, `parallelism` = '2'.

Property	Data type	Description	Default value
parallelism	INTEGER	The degree of parallelism for the task.	1
sink.ignore-update-before	BOOLEAN	Specifies whether to ignore -U during the sink operation.	false
sink.ignore-delete	BOOLEAN	Specifies whether to ignore -D during the sink operation.	false
sink.null-mode	STRING	Specifies whether to write null values during the sink operation. Valid values: NO_OP: Retains and writes the null values from the source data. SKIP: Skips and does not write null values.	NO_OP
udf.xxxx	STRING	Configures a user-defined function (UDF). You must upload the UDF JAR file before you use this property. The parameter uses the format `udf.<udfFunction> = <jarName>#<className>`, where `udfFunction` is the function name, `jarName` is the JAR package name, and `className` is the class name.	None
stream.xxx	ANY	A parameter for the stream engine job. For example, `execution.checkpointing.interval`.	None

Specify the sink table

Parameter	Required	Description
catalog_name	No	The catalog of the sink table.
db_name	No	The database where the sink table is located.
table_name	Yes	The name of the sink table.
column_name	Yes	The column name in the sink table.

SQL search statement (select_statement)

Specifies the new SQL search statement.

Examples

Assume that the source table source and the sink table sink in LindormTable have the following structures:

-- Source table: source
CREATE TABLE source(p1 INT, c1 DOUBLE, PRIMARY KEY(p1));

-- Sink table: sink
CREATE TABLE sink(p1 INT, c1 DOUBLE, PRIMARY KEY(p1));

The following statement creates an ETL task named filter2 and adds properties.

CREATE ETL IF NOT EXISTS filter2
WITH (
`parallelism` = '2',
`stream.execution.checkpointing.interval` = '30000'
)
AS
  INSERT INTO `lindorm_table`.`default`.`sink` (p1, c1)
  SELECT p1, c1 FROM `lindorm_table`.`default`.`source` WHERE c1 > 10;

Modify ETL task properties

The following statement changes the parallelism property to 4.

ALTER ETL filter2
WITH (`parallelism` = '4')
AS
  INSERT INTO `lindorm_table`.`default`.`sink` (p1, c1)
  SELECT p1, c1 FROM `lindorm_table`.`default`.`source`;

Verify the result

Run the DESC ETL filter2; statement to view the ATTRIBUTES of filter2 and confirm that the modification was successful.