最近在Percona的blog上看到一篇文章：Column Store Database Benchmarks: MariaDB ColumnStore vs. Clickhouse vs. Apache Spark，从中可以看到Clickhouse的性能完爆MariaDB ColumnStore和 Spark。于是对Clickhouse产生了浓厚的兴趣，所以也打算进行学习。目前Clickhouse还没有中文文档，学习起来还是有点费劲。Percona的另一篇博客介绍Clickhouse的也可以看看。ClickHouse: New Open Source Columnar Database，其中这里也有一篇文章也可以看看：彪悍开源的分析数据库-ClickHouse
那么ClickHouse到底是啥？
1. 开源的列存储数据库管理系统
2. 支持线性扩展
3. 简单方便
4. 高可靠性
5. 容错（支持多主机异步复制，可以跨多个数据中心部署。 单个节点或整个数据中心的停机时间不会影响系统的读写可用性）
ClickHouse关键功能和应用场景:
更加详细的可以参考官方文档。
目前ClickHouse对ubuntu系统支持比较友好，对于centos就差一点。Ubuntu有deb包可以直接安装。对于centos的则需要自己编译。本人在折腾很久都没有编译出来，最后放弃了。无意中看到了google邮件组中有人提到RPM包，有人搞了yum源，可以直接安装，这才解放。对于想自己编译的同学，可以参考：https://github.com/yandex/ClickHouse/blob/master/doc/build.md，下面进行yum安装
1. 添加yum源
yum-config-manager --add-repo http://repo.red-soft.biz/repos/clickhouse/repo/clickhouse-el6.repo
2. 安装：
yum install clickhouse-server clickhouse-client clickhouse-server-common clickhouse-compressor
3. 添加用户clickhouse
useradd clickhouse
4. 启动clickhouse
/etc/init.d/clickhouse-server start
5. 登录测试：
[root@db_server_yayun_01 ~]# clickhouse-client
ClickHouse client version 1.1..
Connecting to localhost:.
Connected to ClickHouse server version 1.1.. :) select SELECT ┌──┐
│ │
└───┘
→ Progress: 1.00 rows, 1.00 B (64.77 rows/s., 64.77 B/s.)
rows in set. Elapsed: 0.016 sec. :) select now(); SELECT now() ┌───────────────now()─┐
│ -- :: │
└─────────────────────┘
↘ Progress: 1.00 rows, 1.00 B (216.22 rows/s., 216.22 B/s.)
rows in set. Elapsed: 0.005 sec. :)
启动失败可以查看日志，日志的目录默认为
/var/log/clickhouse-server
[root@db_server_yayun_01 clickhouse-server]# ll
total
-rw-rw-rw-. clickhouse clickhouse Mar : clickhouse-server.err.log
-rw-rw-rw-. clickhouse clickhouse Mar : clickhouse-server.log
-rw-rw-rw-. clickhouse clickhouse Mar : stderr
-rw-rw-rw-. clickhouse clickhouse Mar : stdout
[root@db_server_yayun_01 clickhouse-server]#
下面说说clickhouse-client的简单使用：
交互模式
clickhouse-client
clickhouse-client --host=... --port=... --user=... --password=...
启用多行查询：
clickhouse-client -m
clickhouse-client --multiline
对于建表的时候就需要启用多行查询，否则会报错，比如建如下表：
CREATE TABLE `ontime` (
`Year` UInt16,
`Quarter` UInt8,
`Month` UInt8,
`DayofMonth` UInt8,
`DayOfWeek` UInt8,
`FlightDate` Date,
`UniqueCarrier` FixedString(7),
`AirlineID` Int32,
`Carrier` FixedString(2),
`TailNum` String,
`FlightNum` String,
`OriginAirportID` Int32,
`OriginAirportSeqID` Int32,
`OriginCityMarketID` Int32,
`Origin` FixedString(5),
`OriginCityName` String,
`OriginState` FixedString(2),
`OriginStateFips` String,
`OriginStateName` String,
`OriginWac` Int32,
`DestAirportID` Int32,
`DestAirportSeqID` Int32,
`DestCityMarketID` Int32,
`Dest` FixedString(5),
`DestCityName` String,
`DestState` FixedString(2),
`DestStateFips` String,
`DestStateName` String,
`DestWac` Int32,
`CRSDepTime` Int32,
`DepTime` Int32,
`DepDelay` Int32,
`DepDelayMinutes` Int32,
`DepDel15` Int32,
`DepartureDelayGroups` String,
`DepTimeBlk` String,
`TaxiOut` Int32,
`WheelsOff` Int32,
`WheelsOn` Int32,
`TaxiIn` Int32,
`CRSArrTime` Int32,
`ArrTime` Int32,
`ArrDelay` Int32,
`ArrDelayMinutes` Int32,
`ArrDel15` Int32,
`ArrivalDelayGroups` Int32,
`ArrTimeBlk` String,
`Cancelled` UInt8,
`CancellationCode` FixedString(1),
`Diverted` UInt8,
`CRSElapsedTime` Int32,
`ActualElapsedTime` Int32,
`AirTime` Int32,
`Flights` Int32,
`Distance` Int32,
`DistanceGroup` UInt8,
`CarrierDelay` Int32,
`WeatherDelay` Int32,
`NASDelay` Int32,
`SecurityDelay` Int32,
`LateAircraftDelay` Int32,
`FirstDepTime` String,
`TotalAddGTime` String,
`LongestAddGTime` String,
`DivAirportLandings` String,
`DivReachedDest` String,
`DivActualElapsedTime` String,
`DivArrDelay` String,
`DivDistance` String,
`Div1Airport` String,
`Div1AirportID` Int32,
`Div1AirportSeqID` Int32,
`Div1WheelsOn` String,
`Div1TotalGTime` String,
`Div1LongestGTime` String,
`Div1WheelsOff` String,
`Div1TailNum` String,
`Div2Airport` String,
`Div2AirportID` Int32,
`Div2AirportSeqID` Int32,
`Div2WheelsOn` String,
`Div2TotalGTime` String,
`Div2LongestGTime` String,
`Div2WheelsOff` String,
`Div2TailNum` String,
`Div3Airport` String,
`Div3AirportID` Int32,
`Div3AirportSeqID` Int32,
`Div3WheelsOn` String,
`Div3TotalGTime` String,
`Div3LongestGTime` String,
`Div3WheelsOff` String,
`Div3TailNum` String,
`Div4Airport` String,
`Div4AirportID` Int32,
`Div4AirportSeqID` Int32,
`Div4WheelsOn` String,
`Div4TotalGTime` String,
`Div4LongestGTime` String,
`Div4WheelsOff` String,
`Div4TailNum` String,
`Div5Airport` String,
`Div5AirportID` Int32,
`Div5AirportSeqID` Int32,
`Div5WheelsOn` String,
`Div5TotalGTime` String,
`Div5LongestGTime` String,
`Div5WheelsOff` String,
`Div5TailNum` String
) ENGINE = MergeTree(FlightDate, (Year, FlightDate), 8192)
以批处理方式运行查询：
clickhouse-client --query='SELECT 1'
echo 'SELECT 1' | clickhouse-client
从指定格式的文件插入数据：
clickhouse-client --query='INSERT INTO table VALUES' < data.txt
clickhouse-client --query='INSERT INTO table FORMAT TabSeparated' < data.tsv
参考资料：