RisingWave基本操作

什么是RisingWave

RisingWave 是一款基于 Apache 2.0 协议开源的分布式流数据库。RisingWave 让用户使用操作传统数据库的方式来处理流数据。通过创建实时物化视图，RisingWave 可以让用户轻松编写流计算逻辑，并通过访问物化视图来对流计算结果进行及时、一致的查询。

安装与启动

Docker 环境

docker run -it --pull=always -p 4566:4566 -p 5691:5691 risingwavelabs/risingwave:latest playground

通过DataGrip连接

创建表格与物化视图

create table t(v1 int, v2 int);
insert into t values(1,10),(2,20),(3,30);
create materialized view mv as select sum(v1) from t;

查询试图

select * from mv;

导入数据

通过datagen生成数据

CREATE TABLE t1 (v1 int, v2 int)

WITH (

connector = 'datagen',

fields.v1.kind = 'sequence',

fields.v1.start = '1',

fields.v2.kind = 'random',

fields.v2.min = '-10',

fields.v2.max = '10',

fields.v2.seed = '1',

datagen.rows.per.second = '10'

) ROW FORMAT JSON;

CREATE SOURCE s1 (w1 int, w2 int)

WITH (

connector = 'datagen',

fields.w1.kind = 'sequence',

fields.w1.start = '1',

fields.w2.kind = 'random',

fields.w2.min = '-10',

fields.w2.max = '10',

fields.w2.seed = '1',

datagen.rows.per.second = '10'

) ROW FORMAT JSON;

查询创建的表

show tables;

查询source

show sources;

查询结果

Source不支持直接查询

进行流计算

create materialized view mv_t1 as select count(*) from t1;

create materialized view mv_s1 as select count(*) from s1;

从kafka topic中创建source数据

-- 创建kafka source
CREATE SOURCE from_kafka2 (name2 string,id2 string,table2 string
)
INCLUDE offsetinclude timestampinclude  partition
WITH (connector = 'kafka',topic = 'kafka-send2',properties.bootstrap.server = '192.168.5.xxx:9092'
)
FORMAT PLAIN  ENCODE json;

kafka中数据格式

查询结果

-- 不指定结构创建source

CREATE SOURCE from_kafka5 (content2 bytea
)
INCLUDE offsetinclude timestampinclude  partition
WITH (connector = 'kafka',topic = 'kafka-send2',properties.bootstrap.server = '192.168.5.xxx:9092'
)
FORMAT PLAIN  ENCODE BYTES;

-- json处理函数

SELECT ('{"a": {"b":"foo"}}'::jsonb -> 'a') ::jsonb ->> 'b';select convert_from(content2,  'utf8') from from_kafka5;
select to_jsonb(encode(content2,  'base64')) from from_kafka5;select to_jsonb(convert_from(content2,  'utf8')) from from_kafka5;select to_jsonb(content2) from from_kafka5;select convert_from(content2,  'utf8') :: jsonb ->> 'id2',convert_from(content2,  'utf8') :: jsonb ->> 'table2',convert_from(content2,  'utf8') :: jsonb ->> 'name2' from from_kafka5;select jsonb_typeof(encode(content2,  'escape') :: jsonb -> 'id2')  from from_kafka5;select jsonb_extract_path(to_jsonb(convert_from(content2,  'utf8')), 'id2') from from_kafka5;

-- 统计查询

SELECT content2 FROM from_kafka5 where to_char(_rw_kafka_timestamp, 'YYYYMMDDHH24MI') = '202405090846' order by _rw_kafka_timestamp;SELECT to_char(date_trunc('minute', _rw_kafka_timestamp), 'YYYYMMDDHH24MISS') AS period, max(_rw_kafka_offset) as logEndOffset,min(_rw_kafka_offset),(max(_rw_kafka_offset)::INTEGER   - min(_rw_kafka_offset)::INTEGER + 1) as addOffset,'from_kafka5' as topic
FROM from_kafka5 where _rw_kafka_timestamp + INTERVAL '24 hour' > now()group by date_trunc('minute', _rw_kafka_timestamp)
order by period;