ClickHouse
The ClickHouse connector (CONNECTOR_TYPE=clickhouse) translates GQL queries
into ClickHouse-dialect SQL and executes them via the ClickHouse HTTP interface.
It requires a mapping file that maps graph
patterns to ClickHouse tables.
1. Start ClickHouse
docker network create memgql-net
docker run -d --rm \
--name clickhouse-dev \
--network memgql-net \
-p 9000:9000 \
-p 8123:8123 \
--ulimit nofile=262144:262144 \
-e CLICKHOUSE_DEFAULT_ACCESS_MANAGEMENT=1 \
-e CLICKHOUSE_PASSWORD="" \
clickhouse/clickhouse-server:latest2. Seed data
docker exec -i clickhouse-dev clickhouse-client << 'SQL'
CREATE TABLE IF NOT EXISTS persons (
id UInt32,
name String,
age UInt32
) ENGINE = MergeTree() ORDER BY id;
CREATE TABLE IF NOT EXISTS companies (
id UInt32,
name String
) ENGINE = MergeTree() ORDER BY id;
CREATE TABLE IF NOT EXISTS knows (
from_id UInt32,
to_id UInt32
) ENGINE = MergeTree() ORDER BY (from_id, to_id);
CREATE TABLE IF NOT EXISTS works_at (
person_id UInt32,
company_id UInt32
) ENGINE = MergeTree() ORDER BY (person_id, company_id);
INSERT INTO persons VALUES (1, 'Alice', 30), (2, 'Bob', 25);
INSERT INTO companies VALUES (1, 'Acme Corp');
INSERT INTO knows VALUES (1, 2);
INSERT INTO works_at VALUES (1, 1);
SQL3. Start MemGQL
docker run --rm \
--name memgql \
--network memgql-net \
--stop-timeout 2 \
-p 7688:7688 \
--env CONNECTOR_TYPE=clickhouse \
--env CLICKHOUSE_URL=http://clickhouse-dev:8123 \
--env CLICKHOUSE_DB=default \
--env MAPPING_FILE=/data/mapping.json \
--env BOLT_LISTEN_ADDR=0.0.0.0:7688 \
-v ./mapping.json:/data/mapping.json \
memgraph/memgql:latest4. Connect
mgconsole --port 76885. Query
MATCH (p:Person) RETURN p.name, p.age;MATCH (p:Person)-[:WORKS_AT]->(c:Company) RETURN p.name, c.name;MATCH (a:Person)-[:KNOWS]->(b:Person) RETURN a.name, b.name;For environment variables, see Configuration.