什么是TBase?

TBase是一个提供写可靠性，多主节点数据同步的关系数据库集群平台。你可以将TBase配置一台或者 多台主机上，TBase数据存储在多台物理主机上面。数据表的存储有两种方式， 分别是distributed或者replicated ，当向TBase发送查询 SQL时，TBase会自动向数据节点发出查询语句并获取最终结果

TBase采用分布式集群架构（如下图）， 该架构分布式为无共享(share nothing)模式，节点之间相应独立，各自处理自己的数据，处理后的结果可能向上层汇总或在节点间流转，各处理单元之间通过网络协 议进行通信，并行处理和扩展能力更好，这也意味着只需要简单的x86服务器就可以部署TBase数据库集群

下面简单解读一下TBase的三大模块

Coordinator：协调节点（简称CN）

业务访问入口，负责数据的分发和查询规划，多个节点位置对等，每个节点都提供相同的数据库视 图；在功能上CN上只存储系统的全局元数据，并不存储实际的业务数据。

Datanode：数据节点（简称DN）

每个节点还存储业务数据的分片在功能上，DN节点负责完成执行协调节点分发的执行请求。

GTM:全局事务管理器(Global Transaction Manager)

负责管理集群事务信息，同时管理集群的全局对象，比如序列等。 接下来，让我们来看看如何从源码开始，完成到TBase集群环境的搭建。

TBase源码编译安装

创建tbase用户

注意：所有需要安装TBase集群的机器上都需要创建

mkdir /data
useradd -d /data/tbase tbase

源码获取

git clone https://github.com/Tencent/TBase

源码编译

  cd ${SOURCECODE_PATH}
rm -rf ${INSTALL_PATH}/tbase_bin_v2.0 chmod +x configure*
./configure --prefix=${INSTALL_PATH}/tbase_bin_v2.0  --enable-user-switch -- with-openssl  --with-ossp-uuid CFLAGS=-g
make clean make -sj make install
chmod +x contrib/pgxc_ctl/make_signature cd contrib
make -sj make install

本文的使用环境中，上述两个参数如下

${SOURCECODE_PATH}=/data/tbase/TBase-master

${INSTALL_PATH}=/data/tbase/install

集群安装

集群规划

下面以两台服务器上搭建1GTM主，1GTM备，2CN主（CN主之间对等，因此无需备CN），2DN 主，2DN备的集群，该集群为具备容灾能力的最小配置

机器1：10.215.147.158 
机器2：10.240.138.159

集群规划如下

示意图

机器间的ssh互信配置

参考Linux ssh互信配置

环境变量配置

集群所有机器都需要配置

[tbase@TENCENT64 ~]$ vim ~/.bashrc
export TBASE_HOME=/data/tbase/install/tbase_bin_v2.0 export PATH=$TBASE_HOME/bin:$PATH
export LD_LIBRARY_PATH=$TBASE_HOME/lib:${LD_LIBRARY_PATH}

以上，已经配置好了所需要基础环境，可以进入到集群初始化阶段，为了方便用户，TBase提供了 专用的配置和操作工具：pgxcctl来协助用户快速搭建并管理集群，首先需要将前文所述的节点的ip，端口，目录写入到配置文件 pgxcctl.conf 中。

初始化pgxc_ctl.conf文件

[tbase@TENCENT64 ~]$ mkdir /data/tbase/pgxc_ctl [tbase@TENCENT64 ~]$ cd /data/tbase/pgxc_ctl [tbase@TENCENT64 ~/pgxc_ctl]$ vim pgxc_ctl.conf

如下，是结合上文描述的IP，端口，数据库目录，二进制目录等规划来写的pgxc_ctl.conf文件。具 体实践中只需按照自己的实际情况配置好即可.

#!/bin/bash
pgxcInstallDir=/data/tbase/install/tbase_bin_v2.0 pgxcOwner=tbase
defaultDatabase=postgres
pgxcUser=$pgxcOwner tmpDir=/tmp localTmpDir=$tmpDir configBackup=n configBackupHost=pgxc-linker configBackupDir=$HOME/pgxc configBackupFile=pgxc_ctl.bak
#---- GTM ----------
gtmName=gtm gtmMasterServer=10.215.147.158 gtmMasterPort=50001 gtmMasterDir=/data/tbase/data/gtm gtmExtraConfig=none gtmMasterSpecificExtraConfig=none gtmSlave=y gtmSlaveServer=10.240.138.159 gtmSlavePort=50001 gtmSlaveDir=/data/tbase/data/gtm gtmSlaveSpecificExtraConfig=none
#---- Coordinators -------
coordMasterDir=/data/tbase/data/coord coordMasterDir=/data/tbase/data/coord coordArchLogDir=/data/tbase/data/coord_archlog
coordNames=(cn001 cn002 ) coordPorts=(30004 30004 )
poolerPorts=(31110 31110 ) coordPgHbaEntries=(0.0.0.0/0) coordMasterServers=(10.215.147.158 10.240.138.159) coordMasterDirs=($coordMasterDir $coordMasterDir) coordMaxWALsernder=2
coordMaxWALSenders=($coordMaxWALsernder $coordMaxWALsernder ) coordSlave=n
coordSlaveSync=n
coordArchLogDirs=($coordArchLogDir $coordArchLogDir)
coordExtraConfig=coordExtraConfig cat > $coordExtraConfig <<EOF
#================================================
# Added to all the coordinator postgresql.conf # Original: $coordExtraConfig
include_if_exists = '/data/tbase/global/global_tbase.conf'
wal_level = replica wal_keep_segments = 256
max_wal_senders = 4 archive_mode = on archive_timeout = 1800 archive_command = 'echo 0' log_truncate_on_rotation = on
log_filename = 'postgresql-%M.log' log_rotation_age = 4h log_rotation_size = 100MB hot_standby = on
wal_sender_timeout = 30min wal_receiver_timeout = 30min shared_buffers = 1024MB max_pool_size = 2000 log_statement = 'ddl' log_destination = 'csvlog' logging_collector = on log_directory = 'pg_log' listen_addresses = '*' max_connections = 2000
EOF
coordSpecificExtraConfig=(none none) coordExtraPgHba=coordExtraPgHba
cat > $coordExtraPgHba <<EOF
local  all  all    trust
host  all  all  0.0.0.0/0  trust
host  replication  all  0.0.0.0/0  trust
host  all  all  ::1/128  trust
host  replication  all  ::1/128  trust
EOF
coordSpecificExtraPgHba=(none none) coordAdditionalSlaves=n
cad1_Sync=n
#---- Datanodes ---------------------
dn1MstrDir=/data/tbase/data/dn001 dn2MstrDir=/data/tbase/data/dn002 dn1SlvDir=/data/tbase/data/dn001 dn2SlvDir=/data/tbase/data/dn002 dn1ALDir=/data/tbase/data/datanode_archlog dn2ALDir=/data/tbase/data/datanode_archlog
primaryDatanode=dn001 datanodeNames=(dn001 dn002) datanodePorts=(40004 40004)
datanodePoolerPorts=(41110 41110) datanodePgHbaEntries=(0.0.0.0/0) datanodeMasterServers=(10.215.147.158 10.240.138.159) datanodeMasterDirs=($dn1MstrDir $dn2MstrDir) dnWALSndr=4
datanodeMaxWALSenders=($dnWALSndr $dnWALSndr)
datanodeSlave=y  datanodeSlaveServers=(10.240.138.159 10.215.147.158)
datanodeSlavePorts=(50004 54004)
datanodeSlavePoolerPorts=(51110 51110) datanodeSlaveSync=n datanodeSlaveDirs=($dn1SlvDir $dn2SlvDir)
datanodeArchLogDirs=($dn1ALDir/dn001 $dn2ALDir/dn002)
datanodeExtraConfig=datanodeExtraConfig
cat > $datanodeExtraConfig <<EOF #================================================
# Added to all the coordinator postgresql.conf # Original: $datanodeExtraConfig
include_if_exists = '/data/tbase/global/global_tbase.conf' listen_addresses = '*'
wal_level = replica wal_keep_segments = 256
max_wal_senders = 4 archive_mode = on archive_timeout = 1800 archive_command = 'echo 0' log_directory = 'pg_log' logging_collector = on log_truncate_on_rotation = on
log_filename = 'postgresql-%M.log' log_rotation_age = 4h log_rotation_size = 100MB hot_standby = on wal_sender_timeout = 30min wal_receiver_timeout = 30min shared_buffers = 1024MB max_connections = 4000
max_pool_size = 4000 log_statement = 'ddl' log_destination = 'csvlog' wal_buffers = 1GB
EOF
datanodeSpecificExtraConfig=(none none) datanodeExtraPgHba=datanodeExtraPgHba cat > $datanodeExtraPgHba <<EOF
local  all  all    trust
host  all  all  0.0.0.0/0  trust
host  replication  all  0.0.0.0/0  trust
host  all  all  ::1/128  trust
host  replication  all  ::1/128  trust
EOF
datanodeSpecificExtraPgHba=(none none)
datanodeAdditionalSlaves=n walArchive=n

分发二进制包

在一个节点配置好配置文件后，需要预先将二进制包部署到所有节点所在的机器上，这个可以使用pgxc_ctl工具，执行deploy all命令来完成。

[tbase@TENCENT64 ~/pgxc_ctl]$ pgxc_ctl
/usr/bin/bash
Installing pgxc_ctl_bash script as /data/tbase/pgxc_ctl/pgxc_ctl_bash. Installing pgxc_ctl_bash script as /data/tbase/pgxc_ctl/pgxc_ctl_bash. Reading configuration using /data/tbase/pgxc_ctl/pgxc_ctl_bash --home
/data/tbase/pgxc_ctl --configuration /data/tbase/pgxc_ctl/pgxc_ctl.conf Finished reading configuration.
******** PGXC_CTL START ***************
Current directory: /data/tbase/pgxc_ctl PGXC deploy all
Deploying Postgres-XL components to all the target servers. Prepare tarball to deploy ...
Deploying to the server 10.215.147.158. Deploying to the server 10.240.138.159. Deployment done.
登录到所有节点，check二进制包是否分发OK
[tbase@TENCENT64 ~/install]$ ls /data/tbase/install/tbase_bin_v2.0 bin  include  lib  share

执行init all命令，完成集群初始化命令

[tbase@TENCENT64 ~]$ pgxc_ctl
/usr/bin/bash
Installing pgxc_ctl_bash script as /data/tbase/pgxc_ctl/pgxc_ctl_bash. Installing pgxc_ctl_bash script as /data/tbase/pgxc_ctl/pgxc_ctl_bash. Reading configuration using /data/tbase/pgxc_ctl/pgxc_ctl_bash --home
/data/tbase/pgxc_ctl --configuration /data/tbase/pgxc_ctl/pgxc_ctl.conf Finished reading configuration.
******** PGXC_CTL START ***************
Current directory: /data/tbase/pgxc_ctl PGXC init all
Initialize GTM master
....
....
Initialize datanode slave dn001 Initialize datanode slave dn002
mkdir: cannot create directory '/data1/tbase': Permission denied
chmod: cannot access '/data1/tbase/data/dn001': No such file or directory pg_ctl: directory "/data1/tbase/data/dn001" does not exist
pg
_basebackup: could not create directory "/data1/tbase": Permission denied

安装错误处理

一般init集群出错，终端会打印出错误日志，通过查看错误原因，更改配置即可，或者可以通 过/data/tbase/pgxcctl/pgxclog路径下的错误日志查看错误，排查配置文件的错误

通过运行 pgxcctl 工具，执行clean all命令删除已经初始化的文件，修改pgxcctl.conf文件，重新执行init all命令重新发起初始化。

[tbase@TENCENT64 ~]$ pgxc_ctl
/usr/bin/bash
Installing pgxc_ctl_bash script as /data/tbase/pgxc_ctl/pgxc_ctl_bash. Installing pgxc_ctl_bash script as /data/tbase/pgxc_ctl/pgxc_ctl_bash. Reading configuration using /data/tbase/pgxc_ctl/pgxc_ctl_bash --home
/data/tbase/pgxc_ctl --configuration /data/tbase/pgxc_ctl/pgxc_ctl.conf Finished reading configuration.
******** PGXC_CTL START ***************
Current directory: /data/tbase/pgxc_ctl PGXC clean all
[tbase@TENCENT64 ~]$ pgxc_ctl
/usr/bin/bash
Installing pgxc_ctl_bash script as /data/tbase/pgxc_ctl/pgxc_ctl_bash. Installing pgxc_ctl_bash script as /data/tbase/pgxc_ctl/pgxc_ctl_bash. Reading configuration using /data/tbase/pgxc_ctl/pgxc_ctl_bash --home
/data/tbase/pgxc_ctl --configuration /data/tbase/pgxc_ctl/pgxc_ctl.conf Finished reading configuration.
******** PGXC_CTL START ***************
Current directory: /data/tbase/pgxc_ctl PGXC init all
Initialize GTM master
EXECUTE DIRECT ON (dn002) 'ALTER NODE dn002 WITH (TYPE=''datanode'', HOST=''10.240.138.159'', PORT=40004, PREFERRED)';
EXECUTE DIRECT
EXECUTE DIRECT ON (dn002) 'SELECT pgxc_pool_reload()'; pgxc_pool_reload
------------------
t
(1 row)
Done.

查看集群状态

当发现上面的输出时，集群已经OK，另外也可以通过pgxc_ctl工具的monitor all命令来查看集群状态。

[tbase@TENCENT64 ~/pgxc_ctl]$ pgxc_ctl
/usr/bin/bash
Installing pgxc_ctl_bash script as /data/tbase/pgxc_ctl/pgxc_ctl_bash. Installing pgxc_ctl_bash script as /data/tbase/pgxc_ctl/pgxc_ctl_bash. Reading configuration using /data/tbase/pgxc_ctl/pgxc_ctl_bash --home
/data/tbase/pgxc_ctl --configuration /data/tbase/pgxc_ctl/pgxc_ctl.conf Finished reading configuration.
******** PGXC_CTL START ***************
Current directory: /data/tbase/pgxc_ctl PGXC monitor all
Running: gtm master Not running: gtm slave
Running: coordinator master cn001 Running: coordinator master cn002 Running: datanode master dn001 Running: datanode slave dn001

一般的如果配置的不是强同步模式，gtm salve，dn slave的故障不会影响的访问。

集群访问

访问TBase集群基本上和访问单机的PostgreSQL基本上无差别，我们可以通过任意一个CN访问数 据库集群：例如通过连接CN节点select pgxcnode表即可查看集群的拓扑结构（当前的配置下备机不会展示在pgxcnode中），在Linux命令行下通过psql访问的具体示例如下

[tbase@TENCENT64 ~/pgxc_ctl]$ psql -h 10.215.147.158 -p 30004 -d postgres -U tbase
psql (PostgreSQL 10.0 TBase V2)
Type "help" for help.
postgres=# \d
Did not find any relations. postgres=# select * from pgxc_node;
node_name | node_type | node_port |  node_host  | nodeis_primary
nodeis_preferred |  node_id  | node_cluster_name
-----------+-----------+-----------+----------------+----------------+------
------------+------------+-------------------
gtm  | G  |  50001 | 10.215.147.158 | t  | f
|  428125959 | tbase_cluster
cn001  | C  |  30004 | 10.215.147.158 | f  | f
| -264077367 | tbase_cluster
cn002  | C  |  30004 | 10.240.138.159 | f  | f
| -674870440 | tbase_cluster
dn001  | D  |  40004 | 10.215.147.158 | t  | t
| 2142761564 | tbase_cluster
dn002  | D  |  40004 | 10.240.138.159 | f  | f
|  -17499968 | tbase_cluster
(5 rows)

使用数据库前需要创建default group以及sharding表

TBase使用datanode group来增加节点的管理灵活度，要求有一个default group才能使用，因此需要预先创建；一般情况下，会将节点的所有datanode节点加入到default group里。

另外一方面，TBase的数据分布为了增加灵活度，加了中间逻辑层来维护数据记录到物理节点的映 射，我们叫sharding，所以需要预先创建sharding，命令如下：

postgres=# create default node group default_group  with (dn001,dn002); CREATE NODE GROUP
postgres=# create sharding group to group default_group; CREATE SHARDING GROUP

创建数据库，用户，创建表，增删查改等操作

至此，就可以跟使用单机数据库一样来访问数据库集群了

postgres=# create database test; CREATE DATABASE
postgres=# create user test with password 'test'; CREATE ROLE
postgres=# alter database test owner to test; ALTER DATABASE
postgres=# \c test test
You are now connected to database "test" as user "test".
test=> create table foo(id bigint, str text) distribute by shard(id); CREATE TABLE
test=> insert into foo values(1, 'tencent'), (2, 'shenzhen');
COPY 2
test=> select * from foo; id |  str
----+----------
1| tencent
2| shenzhen (2 rows)

停止集群

通过pgxc_ctl工具的stop all命令来停止集群，stop all 后面可以加上参数 -m fast或者是-m immediate来决定如何停止各个节点。

PGXC stop all -m fast
Stopping all the coordinator masters. Stopping coordinator master cn001.
Stopping coordinator master cn002. Done.
Stopping all the datanode slaves. Stopping datanode slave dn001.
Stopping datanode slave dn002.
pg_ctl: PID file "/data/tbase/data/dn002/postmaster.pid" does not exist Is server running?
Stopping all the datanode masters. Stopping datanode master dn001.
Stopping datanode master dn002. Done.
Stop GTM slave
waiting for server to shut down  done
server stopped Stop GTM master
waiting for server to shut down  done
server stopped PGXC monitor all
Not running: gtm master Not running: gtm slave
Not running: coordinator master cn001


Not running: coordinator master cn002
Not running: datanode master dn001 
Not running: datanode slave dn001
Not running: datanode master dn002 
Not running: datanode slave dn002

启动集群

通过pgxc_ctl工具的start all命令来启动集群

[tbase@TENCENT64 ~]$ pgxc_ctl
/usr/bin/bash
Installing pgxc_ctl_bash script as /data/tbase/pgxc_ctl/pgxc_ctl_bash. Installing pgxc_ctl_bash script as /data/tbase/pgxc_ctl/pgxc_ctl_bash. Reading configuration using /data/tbase/pgxc_ctl/pgxc_ctl_bash --home
/data/tbase/pgxc_ctl --configuration /data/tbase/pgxc_ctl/pgxc_ctl.conf Finished reading configuration.
******** PGXC_CTL START ***************
Current directory: /data/tbase/pgxc_ctl PGXC start all

结束语

本文档只是给用户一个简单的指引，演示如何从源码开始，一步一步搭建一个完整的TBase集群， 后续会有更多的文章来介绍TBase的特性使用，优化，问题定位等内容。