Sink data from RisingWave to Redis

This guide describes how to sink data from RisingWave to Redis.

Redis is an open-source, in-memory data structure store, often referred to as a data structure server. RisingWave sinks data to Redis in the form of strings storing key-value pairs in the specified format (JSON or TEMPLATE), so a primary key must always be provided.

You can test out this process on your own device by using the redis-sink demo in the integration_test directory of the RisingWave repository.

Prerequisites

Before sinking data from RisingWave to Redis, please ensure the following:

• The Redis database you want to sink to is accessible from RisingWave.
• Ensure you have an upstream materialized view or source in RisingWave that you can sink data from.

Syntax

CREATE SINK [ IF NOT EXISTS ] sink_name
[FROM sink_from | AS select_query]
WITH (
   connector='redis',
   connector_parameter = 'value', ...
)
FORMAT data_format ENCODE data_encode [ (
    format_parameter = 'value' ) ]
;

Parameters

Parameter Names	Description
redis.url	Required. The address of the Redis database.
primary_key	Required. The primary keys of the sink. If necessary, use ',' to delimit the primary key columns.

Sink parameters

Field	Notes
data_format	Data format. Allowed formats: PLAIN: Output data with insert operations. UPSERT: Output data as a changelog stream.
data_encode	Data encoding. Supported encodings: JSON: date: number of days since the Common Era (CE). interval: P<years>Y<months>M<days>DT<hours>H<minutes>M<seconds>S format string. time without time zone: number of milliseconds past the last midnight. timestamp: number of milliseconds since the Epoch. TEMPLATE: converts data to the string specified by key_format/value_format.
force_append_only	If true, forces the sink to be PLAIN (also known as append-only), even if it cannot be.
key_format	Required if data_encode is TEMPLATE. Specify the format for the key as a string.
value_format	Required if data_encode is TEMPLATE. Specify the format for the value as a string.

Example

Assume we create a materialized view, bhv_mv, from a source.

CREATE MATERIALIZED VIEW bhv_mv AS
SELECT
    user_id,
    target_id,
    event_timestamp
FROM
    source_1;

We can sink data from bhv_mv to Redis by creating a sink. Here, data_encode is JSON.

CREATE SINK redis_sink
FROM bhv_mv WITH (
    connector = 'redis',
    primary_key = 'user_id',
    redis.url= 'redis://127.0.0.1:6379/'
) FORMAT PLAIN ENCODE JSON (
    force_append_only='true'
);

We can sink data from bhv_mv to Redis by creating a sink. Here, data_encode is TEMPLATE, so key_format and value_format must be defined.

CREATE SINK redis_sink_2
FROM bhv_mv WITH (
    primary_key = 'user_id',
    connector = 'redis',
    redis.url= 'redis://127.0.0.1:6379/',
) FORMAT PLAIN ENCODE TEMPLATE (
    force_append_only='true',
    key_format = 'UserID:{user_id}',
    value_format = 'TargetID:{target_id},EventTimestamp{event_timestamp}'
);