https://github.com/Blynk-Technologies/clickhouse4j

Lighter and faster alternative for the official ClickHouse JDBC driver
https://github.com/Blynk-Technologies/clickhouse4j

java jdbc-driver

Last synced: 30 days ago
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Lighter and faster alternative for the official ClickHouse JDBC driver

• Host: GitHub
• URL: https://github.com/Blynk-Technologies/clickhouse4j
• Owner: Blynk-Technologies
• License: other
• Created: 2019-08-23T11:19:15.000Z (over 5 years ago)
• Default Branch: master
• Last Pushed: 2023-02-09T07:15:05.000Z (almost 2 years ago)
• Last Synced: 2024-10-16T01:01:53.958Z (about 2 months ago)
• Topics: java, jdbc-driver
• Language: Java
• Homepage:
• Size: 1.13 MB
• Stars: 212
• Watchers: 6
• Forks: 38
• Open Issues: 21
• Metadata Files:
  • Readme: README.md
  • Changelog: CHANGELOG
  • License: LICENSE

Awesome Lists containing this project

• awesome-clickhouse - Blynk-Technologies/clickhouse4j - Clickhouse4j is a lightweight JDBC driver alternative for ClickHouse designed to enhance performance and simplify integration. (Language bindings / Java)

README

        
Clickhouse4j - lighter and faster alternative for the official ClickHouse JDBC driver

===============

[![Maven Central](https://maven-badges.herokuapp.com/maven-central/cc.blynk.clickhouse/clickhouse4j/badge.svg)](https://mvnrepository.com/artifact/cc.blynk.clickhouse/clickhouse4j) [![clickhouse4j](https://travis-ci.org/blynkkk/clickhouse4j.svg?branch=master)](https://github.com/blynkkk/clickhouse4j)

The main differences between this and the official driver are:

- Removed Guava, Jackson and Apache Http Client dependencies;

- Smaller size - 850kb vs 5.6mb of the original driver (**7x smaller jar size**)

- A bunch of micro optimizations were applied (for example, **batch inserts are now 40% faster**)

- [CopyManager](https://github.com/blynkkk/clickhouse4j/blob/master/src/main/java/cc/blynk/clickhouse/copy/CopyManager.java) added;

- Support for JSON, JSONCompact select;

- Compiled against Java 8 and many [other things](https://github.com/blynkkk/clickhouse4j/blob/master/CHANGELOG)

### Usage

```xml

    cc.blynk.clickhouse

    clickhouse4j

    1.4.4

```

### CopyManager usage

```CopyManager``` is utility class that helps to read / write the queries from / to the file/stream/reader.

##### Select from DB to File

```

String query = "SELECT * from copy_manager_test.my_table FORMAT CSVWithNames";

Path outputFile = ...;

try (CopyManager copyManager = CopyManagerFactory.create(dataSource)) {

    copyManager.copyFromDb(query, outputFile);

}

//outputFile now has all the data and headers from the copy_manager_test DB and my_table table

```

##### Select from DB to File with prepared statement

```

try (Connection connection = dataSource.getConnection();

     PreparedStatement ps = connection.prepareStatement(sql);

     CopyManager copyManager = CopyManagerFactory.create(connection)) {

        ps.setLong(1, id);

        copyManager.copyFromDb(ps, outputStream);

}

```

##### Insert from File to DB

```

String query = "INSERT INTO copy_manager_test.my_table FORMAT CSV";

Path inputFile = ...;

try (CopyManager copyManager = CopyManagerFactory.create(dataSource)) {

    copyManager.copyToDb(query, inputFile);

}

//DB copy_manager_test and my_table table now has all csv data from the inputFile

```

##### Select as JSON

```

ResultSet rs = connection.createStatement().executeQuery("SELECT * FROM test.my_table FORMAT JSON");

if (rs.next()) {

    return rs.getString("json");

}

//respone example:

{

	"meta":

	[

		{

			"name": "created",

			"type": "DateTime"

		},

		{

			"name": "value",

			"type": "Int32"

		}

	],

	"data":

	[

		{

			"created": "2019-11-17 11:31:22",

			"value": 1

		},

		{

			"created": "2019-11-17 11:31:22",

			"value": 2

		}

	],

	"rows": 2,

	"statistics":

	{

		"elapsed": 0.000312306,

		"rows_read": 2,

		"bytes_read": 16

	}

}

```

### Migration from the official driver

All you need to do is replace:

`ru.yandex.clickhouse.ClickHouseDriver` to `cc.blynk.clickhouse.ClickHouseDriver`

URL syntax: 

`jdbc:clickhouse://:[/]`, e.g. `jdbc:clickhouse://localhost:8123/test`

JDBC Driver Class:

`cc.blynk.clickhouse.ClickHouseDriver`

additionally, if you have a few instances, you can use `BalancedClickhouseDataSource`.

### Build requirements

In order to build the jdbc client one needs to have jdk 1.8 or higher.

### Compiling with maven

`mvn package -DskipTests=true`

To build a jar with dependencies use

`mvn package assembly:single -DskipTests=true`