一、概述

pgCenter的主要目标是帮助Postgres DBA管理他们在数据库中拥有的统计数据，通过内置统计数据视图和函数，以方便的格式查看所有必要的数据。

1. 主要特征

• 类似于TOP的界面，可随时监控统计信息的变化
• 配置管理功能允许查看和编辑当前配置文件，并在需要时重新加载服务
• 日志文件功能允许您快速检查Postgres日志，而无需停止统计信息监视
• "Poor man’s monitoring"，允许将Postgres统计信息收集到文件中，并在以后构建报告

2. 统计指标

• current summary activity - 不同来源的一系列指标汇总，包括：postgres uptime, version, recovery status, number of clients grouped by their states, number of (auto)vacuums, statements per second, age of the longest transaction and the longest vacuum
• pg_stat_activity - 已连接客户端和Postgres后台进程的当前活动相关的信息
• pg_stat_database - 数据库的统计信息，例如提交/回滚的数量，处理的元组，死锁，临时文件等
• pg_stat_replication - 有关复制，已连接备用主机及其活动的统计信息
• pg_stat_user_tables，pg_statio_user_tables - 对表的访问（包括IO）的统计信息
• pg_stat_user_indexes，pg_statio_user_indexes - 对索引的访问（包括IO）的统计信息
• pg_stat_user_functions - 关于函数执行的统计信息
• pg_stat_statements - 执行的S​​QL语句的统计信息，包括时间和资源使用情况
• pg_stat_progress_vacuum - 有关autovacuum进程状态的信息

二、安装

-- 使用release版本就可以了
-- 下载地址 https://github.com/lesovsky/pgcenter/releases，下载后解压就可以使用了
[root@localhost ~]# tar zxf pgcenter.linux-amd64.tar.gz
[root@localhost ~]# mkdir /opt/pgcenter
[root@localhost ~]# mv pgcenter /opt/pgcenter
[root@localhost ~]# echo "export PATH=$PATH:/opt/pgcenter" >>/etc/bashrc
[root@localhost ~]# source /etc/bashrc
[root@localhost ~]# pgcenter --version
pgcenter 0.5.0

三、参数说明

[root@localhost ~]# pgcenter -?
pgCenter is a command line admin tool for PostgreSQL.

Usage:
  pgcenter [flags]
  pgcenter [command] [command-flags] [args]

Available commands:
  config        configures Postgres to work with pgcenter
  record        record stats to file
  report        make report based on previously saved statistics
  top           top-like stats viewer

Flags:
  -?, --help            show this help and exit
      --version         show version information and exit

Use "pgcenter [command] --help" for more information about a command.

pgcenter config：安装pgcenter用来统计的一些sql函数

-- 安装示例，指定安装到test数据库
-- 该步骤需要test数据库安装了plperlu，及perl模块Linux::Ethtool::Settings
[root@localhost ~]# perl -MCPAN -e shell
cpan[1]> install Linux::Ethtool::Settings
cpan[1]> q
[root@localhost ~]# su - postgres
[postgres@localhost ~]$ psql -d test
psql (8.4.18, server 10.5)
WARNING: psql version 8.4, server version 10.0.
         Some psql features might not work.
Type "help" for help.

test=# CREATE LANGUAGE plperlu;
test=# \q
[postgres@localhost ~]$ exit
[root@localhost ~]# pgcenter config -i -d test -U postgres
Statistics schema installed.

以下是pgcenter config的参数

[root@localhost ~]# pgcenter config -?
'pgcenter config' configures Postgres to work with pgcenter

Usage:
  pgcenter config [OPTIONS]... [DBNAME [USERNAME]]

Options:
  -i, --install                 install pgcenter's stats schema
  -u, --uninstall               uninstall pgcenter's stats schema
  -d, --dbname DBNAME           database name to connect to
  -h, --host HOSTNAME           database server host or socket directory.
  -p, --port PORT               database server port (default 5432)
  -U, --username USERNAME       database user name

General options:
  -?, --help            show this help and exit
      --version         show version information and exit

pgcenter top：为Postgres统计提供top界面，具有扩展的功能集
pgcenter top 命令参数

[root@localhost ~]# pgcenter top -?
'pgcenter top' is the top-like stats viewer.

Usage:
  pgcenter top [OPTIONS]... [DBNAME [USERNAME]]

Options:
  -d, --dbname DBNAME           database name to connect to
  -h, --host HOSTNAME           database server host or socket directory.
  -p, --port PORT               database server port (default 5432)
  -U, --username USERNAME       database user name

General options:
  -?, --help            show this help and exit
      --version         show version information and exit

pgcenter top 交互式命令

Help for interactive commands

general actions:
    a,d,f,r     mode: 'a' activity, 'd' databases, 'f' functions, 'r' replication, 
    s,t,i,v           's' tables sizes, 't' tables, 'i' indexes, 'v' vacuum progress,
    x,X            mit'x' pg_stat_statements switch, 'X' pg_stat_statements menu.
    Left,Right,<,/    'Left,Right' change column sort, '<' desc/asc sort toggle, '/' set filter. 
    C,E,R       config: 'C' show config, 'E' edit configs, 'R' reload config.
    p                 start psql session.
    l                 open log file with pager. 

aux stats actions:
    B,N,L       'B' diskstat, 'N' nicstat, 'L' logtail. 

activity actions: 
    -,_         '-' cancel backend by pid, '_' terminate backend by pid.
    n,m         'n' set new mask, 'm' show current mask.
    k,K         'k' cancel group of queries using mask, 'K' terminate group of backends using mask
    I           show IDLE connections toggle.
    A           change activity age threshold.
    G           get query report.

other actions:
    , Q         ',' show system tables on/off, 'Q' reset postgresql statistics counters.
    z,Z         'z' set refresh interval, 'Z' change color scheme.
    space       pause program execution.
    h,F1        show this tab.
    Ctrl+Q      quit.

Type 'Esc' to continue.

四、测试

使用pgbench进行压力测试，用pgcenter监控postgresql，pgcenter与postgresql在同一台机器上

-- pgbench初始化压力测试表，默认已创建了pgbench库
[postgres@localhost ~]$ pgbench -i --unlogged-tables -s 16 pgbench
-- pgbench用例，8客户端
[postgres@localhost ~]$ pgbench -r -c 8 -T 120 pgbench
-- pgcenter top 监控，每秒刷新
[root@localhost ~]# pgcenter top -d pgbench -U postgres

pgcenter也可以监控远程postgresql，但是需要远程postgresql也有pgcenter，并创建了相应的sql函数和视图，否则功能不可用，另外某些功能不支持远程postgresql。
pgcenter top 部分截图

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