ALTER SOURCE

The ALTER SOURCE command modifies the definition of a source.

Syntax

ALTER SOURCE current_source_name 
    alter_option;

alter_option depends on the operation you want to perform on the source. For all supported clauses, see the sections below.

Clause

ADD COLUMN

Syntax

ALTER SOURCE source_name 
    ADD COLUMN col_name data_type;

Parameter or clause	Description
ADD COLUMN	This clause adds a column to the specified source.
col_name	The name of the new column you want to add to the source.
data_type	The data type of the newly added column. With the struct data type, you can create a nested table. Elements in a nested table need to be enclosed with angle brackets ("<>").

Example

-- Add a column named "v3" to a source named "src1" 
ALTER SOURCE src1 
    ADD COLUMN v3 int;

note

• To alter columns in a source created with a schema registry, see FORMAT and ENCODE options.

• You cannot add a primary key column to a source or table in RisingWave. To modify the primary key of a source or table, you need to recreate the table.

• You cannot remove a column from a source in RisingWave. If you intend to remove a column from a source, you'll need to drop the source and create the source again.

RENAME TO

Syntax

ALTER SOURCE source_name 
    RENAME TO new_source_name;

Parameter or clause	Description
RENAME TO	This clause changes the name of the source.
new_source_name	The new name of the source.

Example

-- Change the name of a source named "src" to "src1"
ALTER SOURCE src 
   RENAME TO src1;

OWNER TO

Syntax

ALTER SOURCE current_source_name 
    OWNER TO new_user;

Parameter or clause	Description
OWNER TO	This clause changes the owner of the source.
new_user	The new owner you want to assign to the source.

Example

-- Change the owner of the source named "src" to user "user1"
ALTER SOURCE src OWNER TO user1;

SET SCHEMA

Syntax

ALTER SOURCE current_source_name
    SET SCHEMA schema_name;

Parameter or clause	Description
SET SCHEMA	This clause moves the source to a different schema.
schema_name	The name of the schema to which the source will be moved.

Example

-- Move the source named "test_source" to the schema named "test_schema"
ALTER SOURCE test_source SET SCHEMA test_schema;

FORMAT and ENCODE options

At present, combined with the ALTER SOURCE command, you can refresh the schema registry of a source by refilling the FORMAT and ENCODE options. For more details about these options, see CREATE SOURCE.

Syntax

ALTER SOURCE source_name FORMAT data_format ENCODE data_encode [ (
    message='message',
    schema.location='location', ...) ];

Here is an example. Let's assume the original FORMAT and ENCODE options are as follows:

Example

-- Create a source.
CREATE SOURCE src_user WITH (
    connector = 'kafka',
    topic = 'sr_pb_test',
    properties.bootstrap.server = 'message_queue:29092',
    scan.startup.mode = 'earliest'
)
FORMAT PLAIN ENCODE PROTOBUF(
    schema.registry = 'http://message_queue:8081',
    message = 'test.User');

Then you can refresh the schema registry by the following command:

Example

ALTER SOURCE src_user FORMAT PLAIN ENCODE PROTOBUF(
    schema.registry = 'http://message_queue:8081',
    message = 'test.UserWithMoreFields'
);

note

Currently, it is not supported to modify the data_format and data_encode. Furthermore, when refreshing the schema registry of a source, it is not allowed to drop columns or change types.