ClickHouse Java Client & JDBC Driver
Java client and JDBC driver for ClickHouse. Java client is async, lightweight, and low-overhead library for ClickHouse; while JDBC driver is built on top of the Java client with more dependencies and extensions for JDBC-compliance. Java 8 or higher is required to use Java client(clickhouse-client) and/or JDBC driver(clickhouse-jdbc). In addition, starting from 0.3.2, JDBC driver only works with ClickHouse 20.7+, so please consider to either upgrade server to one of active releases or downgrade the driver to 0.3.1-patch(not recommended).
❗ IMPORTANT
Maven groupId ru.yandex.clickhouse and legacy JDBC driver ru.yandex.clickhouse.ClickHouseDriver have been deprecated and no longer receive updates.
Please use new groupId com.clickhouse and driver com.clickhouse.jdbc.ClickHouseDriver instead. It's highly recommended to upgrade to 0.3.2+ now for improved performance and stability.
Note: in general, the new driver(v0.3.2+) is a few times faster with less memory usage. More information can be found at here.
Features
| Category | Feature | Supported | Remark |
|---|---|---|---|
| API | JDBC | ✅ | |
| R2DBC | ❌ | will be supported in 0.3.3 | |
| GraphQL | ❌ | ||
| Protocol | HTTP | ✅ | recommended, defaults to java.net.HttpURLConnection and can be changed to java.net.http.HttpClient(less stable) |
| gRPC | ✅ | still experimental, works with 22.3+, known to has issue when using LZ4 compression | |
| TCP/Native | ✅ | clickhouse-cli-client(wrapper of ClickHouse native command-line client) was added in 0.3.2-patch10, clickhouse-tcp-client will be available in 0.3.3 |
|
| Local/File | ❌ | clickhouse-cli-client will be enhanced to support clickhouse-local |
|
| Compatibility | Server < 20.7 | ❌ | use 0.3.1-patch(or 0.2.6 if you're stuck with JDK 7) |
| Server >= 20.7 | ✅ | use 0.3.2 or above. All active releases are supported. | |
| Compression | gzip | ✅ | |
| lz4 | ✅ | default | |
| zstd | ❌ | ||
| Data Format | RowBinary | ✅ | RowBinaryWithNamesAndTypes for query and RowBinary for insertion |
| TabSeparated | ✅ | Does not support as many data types as RowBinary | |
| Data Type | AggregatedFunction | ❌ | limited to groupBitmap |
| Array(*) | ✅ | ||
| Bool | ✅ | ||
| Date* | ✅ | ||
| DateTime* | ✅ | ||
| Decimal* | ✅ | SET output_format_decimal_trailing_zeros=1 in 21.9+ for consistency |
|
| Enum* | ✅ | can be treated as both string and integer | |
| Geo Types | ✅ | Point, Ring, Polygon, and MultiPolygon | |
| Int*, UInt* | ✅ | UInt64 is mapped to long |
|
| IPv* | ✅ | ||
| Map(*) | ✅ | ||
| Nested(*) | ✅ | ||
| Object('JSON') | ✅ | supported since 0.3.2-patch8 | |
| SimpleAggregateFunction | ✅ | ||
| *String | ✅ | ||
| Tuple(*) | ✅ | ||
| UUID | ✅ | ||
| High Availability | Load Balancing | ✅ | supported since 0.3.2-patch10 |
| Failover | ✅ | supported since 0.3.2-patch10 | |
| Transaction | Transaction | ✅ | supported since 0.3.2-patch11, use ClickHouse 22.7+ for native implicit transaction support |
| Savepoint | ❌ | ||
| XAConnection | ❌ |
Usage
The library can be downloaded from both Github Releases and Maven Central. Development snapshots are available on Sonatype OSSRH.
<repositories>
<repository>
<id>ossrh</id>
<name>Sonatype OSSRH</name>
<url>https://s01.oss.sonatype.org/content/repositories/snapshots/</url>
</repository>
</repositories>Java Client
<dependency>
<groupId>com.clickhouse</groupId>
<!-- or clickhouse-grpc-client if you prefer gRPC -->
<artifactId>clickhouse-http-client</artifactId>
<version>0.3.2-patch11</version>
</dependency>// endpoint: protocol://host[:port][/database][?param[=value][¶m[=value]][#tag[,tag]]
ClickHouseNode endpoint = ClickHouseNode.of("https://localhost"); // http://localhost:8443?ssl=true&sslmode=NONE
// endpoints: [defaultProtocol://]endpoint[,endpoint][/defaultDatabase][?defaultParameters][#defaultTags]
ClickHouseNodes endpoints = ClickHouseNodes.of("http://(https://explorer@play.clickhouse.com:443),localhost,"
+ "(tcp://localhost?!auto_discovery#experimental),(grpc://localhost#experimental)?failover=3#test")
try (ClickHouseClient client = ClickHouseClient.newInstance(ClickHouseProtocol.HTTP);
ClickHouseResponse response = client.connect(endpoint) // or client.connect(endpoints)
// you'll have to parse response manually if using a different format
.format(ClickHouseFormat.RowBinaryWithNamesAndTypes)
.query("select * from numbers(:limit)")
.params(1000).executeAndWait()) {
// or response.stream() if you prefer stream API
for (ClickHouseRecord r : response.records()) {
int num = r.getValue(0).asInteger();
// type conversion
String str = r.getValue(0).asString();
LocalDate date = r.getValue(0).asDate();
}
ClickHouseResponseSummary summary = response.getSummary();
long totalRows = summary.getTotalRowsToRead();
}JDBC Driver
<dependency>
<!-- please stop using ru.yandex.clickhouse as it's been deprecated -->
<groupId>com.clickhouse</groupId>
<artifactId>clickhouse-jdbc</artifactId>
<version>0.3.2-patch11</version>
<!-- use uber jar with all dependencies included, change classifier to http for smaller jar -->
<classifier>all</classifier>
<exclusions>
<exclusion>
<groupId>*</groupId>
<artifactId>*</artifactId>
</exclusion>
</exclusions>
</dependency>// jdbc:(ch|clickhouse):[defaultProtocol://]endpoint[,endpoint][/defaultDatabase][?defaultParameters][#defaultTags]
String url = "jdbc:ch:https://play.clickhouse.com:443";
Properties properties = new Properties();
properties.setProperty("user", "explorer");
properties.setProperty("password", "");
// optional properties
properties.setProperty("client_name", "Agent #1");
...
ClickHouseDataSource dataSource = new ClickHouseDataSource(url, properties);
try (Connection conn = dataSource.getConnection();
Statement stmt = conn.createStatement();
ResultSet rs = stmt.executeQuery("show databases")) {
...
}More examples can be found at here.
Build with Maven
Use mvn -DskipITs clean verify to compile and generate packages if you're using JDK 8. To create a multi-release jar (see JEP-238), please use JDK 11+ with ~/.m2/toolchains.xml like below, and run mvn -Drelease -DskipITs clean verify instead.
<?xml version="1.0" encoding="UTF8"?>
<toolchains>
<toolchain>
<type>jdk</type>
<provides>
<version>11</version>
</provides>
<configuration>
<jdkHome>/usr/lib/jvm/java-11-openjdk</jdkHome>
</configuration>
</toolchain>
<toolchain>
<type>jdk</type>
<provides>
<version>17</version>
</provides>
<configuration>
<jdkHome>/usr/lib/jvm/java-17-openjdk</jdkHome>
</configuration>
</toolchain>
</toolchains>Testing
By default, docker is required to run integration test. Docker image(defaults to clickhouse/clickhouse-server) will be pulled from Internet, and containers will be created automatically by testcontainers before testing. To test against specific version of ClickHouse, you can pass parameter like -DclickhouseVersion=22.3 to Maven.
In the case you don't want to use docker and/or prefer to test against an existing server, please follow instructions below:
- make sure the server can be accessed using default account(user
defaultand no password), which has both DDL and DML privileges - add below two configuration files to the existing server and expose all defaults ports for external access
- make sure ClickHouse binary(usually
/usr/bin/clickhouse) is available in PATH, as it's required to testclickhouse-cli-client - put
test.propertiesunder either~/.clickhouseorsrc/test/resourcesof your project, with content like below:clickhouseServer=x.x.x.x # below properties are only useful for test containers #clickhouseVersion=latest #clickhouseTimezone=UTC #clickhouseImage=clickhouse/clickhouse-server #additionalPackages=
Benchmark
To benchmark JDBC drivers:
cd clickhouse-benchmark
mvn -Drelease clean package
# single thread mode
java -DdbHost=localhost -jar target/benchmarks.jar -t 1 \
-p client=clickhouse-jdbc -p connection=reuse \
-p statement=prepared Query.selectInt8It's time consuming to run all benchmarks against all drivers using different parameters for comparison. If you just need some numbers to understand performance, please refer to this(still have plenty of room to improve according to ranking at here).