ClickHouse 高性能数据库

ClickHouse 是一款 开源、高性能的列式数据库，主要用于 大规模数据分析 (OLAP) 和 实时查询。它的特点是：

  • 列式存储，读取指定列非常快
  • 支持高并发写入和查询
  • 强大的聚合功能，适合报表和日志分析
  • 支持 SQL 查询，易上手

1️. 安装与快速开始

可以参考官方文档或社区教程 👉ClickHouse 官方文档

1.1 安装

curl https://clickhouse.com/ | sh
sudo ./clickhouse install

1.2 运行

$ clickhouse-client --host server

ClickHouse client version 24.12.2.29 (official build).
Connecting to server:9000 as user default.
Connected to ClickHouse server version 24.12.2.

:)

Specify additional connection details as necessary:

OptionDescription
--port <port>The port ClickHouse server is accepting connections on. The default ports are 9440 (TLS) and 9000 (no TLS). Note that ClickHouse Client uses the native protocol and not HTTP(S).
-s [--secure]Whether to use TLS (usually autodetected).
-u [--user] <username>The database user to connect as. Connects as the default user by default.
--password <password>The password of the database user. You can also specify the password for a connection in the configuration file. If you do not specify the password, the client will ask for it.
-c [--config] <path-to-file>The location of the configuration file for ClickHouse Client, if it is not at one of the default locations. See Configuration Files.

1.3 退出

To exit the client, press Ctrl+D, or enter one of the following instead of a query:

  • exit or exit;
  • quit or quit;
  • q, Q or :q
  • logout or logout;

2. 库和表的创建

在 ClickHouse 中，数据存储的基本单元是 数据库（Database） 和 表（Table）。
下面是创建库和表的示例：

2.1 创建数据库

CREATE DATABASE IF NOT EXISTS analytics;

  • IF NOT EXISTS → 避免数据库已存在时报错

  • analytics → 数据库名称，可以根据业务自定义

2.2 创建表

CREATE TABLE IF NOT EXISTS analytics.visits (
    user_id UInt32,
    page_id UInt32,
    timestamp DateTime
) ENGINE = MergeTree()
ORDER BY timestamp;

  • MergeTree() → 高性能表引擎

  • ORDER BY timestamp → 按时间列排序优化查询

  • IF NOT EXISTS → 避免表已存在时报错

3. 数据写入与查询

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