Support Query ClickHouse AggregatingMergeTree Engine Table.

[FayeSpica]

Enhancement

StarRocks as Query Engine

Our team is trying to use StarRocks as a unified query engine layer. We are encountering issues when querying materialized views in ClickHouse.

e.g.

ClickHouse

CREATE DATABASE db0;
CREATE TABLE db0.simple (id UInt64, val SimpleAggregateFunction(sum, UInt64)) ENGINE=AggregatingMergeTree() ORDER BY id;
INSERT INTO db0.simple(id, val) VALUES (1, 10),(1, 11),(2, 12);

Expected Result

ClickHouse :) select id, sum(val) from db0.simple GROUP BY id;

SELECT
    id,
    sum(val)
FROM db0.simple
GROUP BY id

Query id: da27ce92-1f98-4790-9a3d-00f5e9d72b03

   ┌─id─┬─sum(val)─┐
1. │  2 │       12 │
2. │  1 │       21 │
   └────┴──────────┘

2 rows in set. Elapsed: 0.004 sec.

StarRocks

CREATE EXTERNAL CATALOG clickhouse
COMMENT 'example'
PROPERTIES
(
    "type"="jdbc", 
    "user"="default",
    "password"="",
    "jdbc_uri"="jdbc:clickhouse:[your ClickHouse address]:8123",
    "driver_url"="file:///[url]/clickhouse-jdbc-0.7.1-all.jar",
    "driver_class"="com.clickhouse.jdbc.ClickHouseDriver"
);

Query ClickHouse table from StarRocks

SELECT id, sum(val) FROM clickhouse.db0.simple GROUP BY id;

Got Error:

ERROR 1064 (HY000): Getting analyzing error. Detail message: Datatype of external table column [val] is not supported!.

Features Required

1. Support AggregateFuntion types
2. Support Aggregation pushdown