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 [ (
    key = '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.

FORMAT and ENCODE options

note

These options should be set in FORMAT data_format ENCODE data_encode (key = 'value'), instead of the WITH clause

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}'
);