PostgreSQL中定时job执行(pgAgent)
PostgreSQL中定时job执行
业务分析
近期项目需要定期清理数据库中的多余数据，即每月1号删除指定表中一年以上的数据。
初步分析这种定时job可以使用一下两种技术实现：
- Linux的crontab功能
- pgadmin的pgAgent功能
为了避免数据库系统和操作系统的绑定，最后决定在数据库层面实现自动清理功能，即使用pgAgent功能
介绍
pgAgent是pgAdmin III工具中的一个插件，它在pgAdmin III v1.4版本中引用。
主要用于PostgreSQL的作业调度代理，能够在复杂的时间表上运行多步批处理shell和SQL任务。
需要注意的是，pgAgent需要一些数据库表和其他对象的支持,因此需要先安装pgAgent数据库。
环境
- PostgreSQL:
操作系统：CentOS Linux release 7.3.1611 (Core)
数据库系统： PostgreSQL 9.5.8
IP： 192.168.230.134
port: 5432安装
安装pgAdmin III
yum install pgadmin3_95.x86_64 输入：
[root@localhost ~]# yum install pgadmin3_95.x86_64
Loaded plugins: fastestmirror, langpacks
base | 3.6 kB 00:00:00
epel/x86_64/metalink | 6.4 kB 00:00:00
extras | 3.4 kB 00:00:00
pgdg95 | 4.1 kB 00:00:00
updates | 3.4 kB 00:00:00
Loading mirror speeds from cached hostfile
* base: mirrors.163.com
* epel: mirrors.tuna.tsinghua.edu.cn
* extras: mirrors.163.com
* updates: mirrors.163.com
Resolving Dependencies
--> Running transaction check
---> Package pgadmin3_95.x86_64 0:1.22.1-1.rhel7 will be installed
--> Processing Dependency: wxGTK for package: pgadmin3_95-1.22.1-1.rhel7.x86_64
--> Processing Dependency: libwx_gtk2u_xrc-2.8.so.0(WXU_2.8)(64bit) for package: pgadmin3_95-1.22.1-1.rhel7.x86_64
--> Processing Dependency: libwx_gtk2u_stc-2.8.so.0(WXU_2.8)(64bit) for package: pgadmin3_95-1.22.1-1.rhel7.x86_64
--> Processing Dependency: libwx_gtk2u_html-2.8.so.0(WXU_2.8)(64bit) for package: pgadmin3_95-1.22.1-1.rhel7.x86_64
--> Processing Dependency: libwx_gtk2u_core-2.8.so.0(WXU_2.8)(64bit) for package: pgadmin3_95-1.22.1-1.rhel7.x86_64
--> Processing Dependency: libwx_gtk2u_aui-2.8.so.0(WXU_2.8.5)(64bit) for package: pgadmin3_95-1.22.1-1.rhel7.x86_64
--> Processing Dependency: libwx_gtk2u_aui-2.8.so.0(WXU_2.8)(64bit) for package: pgadmin3_95-1.22.1-1.rhel7.x86_64
--> Processing Dependency: libwx_gtk2u_adv-2.8.so.0(WXU_2.8)(64bit) for package: pgadmin3_95-1.22.1-1.rhel7.x86_64
--> Processing Dependency: libwx_baseu_xml-2.8.so.0(WXU_2.8)(64bit) for package: pgadmin3_95-1.22.1-1.rhel7.x86_64
--> Processing Dependency: libwx_baseu_net-2.8.so.0(WXU_2.8)(64bit) for package: pgadmin3_95-1.22.1-1.rhel7.x86_64
--> Processing Dependency: libwx_baseu-2.8.so.0(WXU_2.8.5)(64bit) for package: pgadmin3_95-1.22.1-1.rhel7.x86_64
--> Processing Dependency: libwx_baseu-2.8.so.0(WXU_2.8)(64bit) for package: pgadmin3_95-1.22.1-1.rhel7.x86_64
--> Processing Dependency: libwx_gtk2u_xrc-2.8.so.0()(64bit) for package: pgadmin3_95-1.22.1-1.rhel7.x86_64
--> Processing Dependency: libwx_gtk2u_stc-2.8.so.0()(64bit) for package: pgadmin3_95-1.22.1-1.rhel7.x86_64
--> Processing Dependency: libwx_gtk2u_html-2.8.so.0()(64bit) for package: pgadmin3_95-1.22.1-1.rhel7.x86_64
--> Processing Dependency: libwx_gtk2u_core-2.8.so.0()(64bit) for package: pgadmin3_95-1.22.1-1.rhel7.x86_64
--> Processing Dependency: libwx_gtk2u_aui-2.8.so.0()(64bit) for package: pgadmin3_95-1.22.1-1.rhel7.x86_64
--> Processing Dependency: libwx_gtk2u_adv-2.8.so.0()(64bit) for package: pgadmin3_95-1.22.1-1.rhel7.x86_64
--> Processing Dependency: libwx_baseu_xml-2.8.so.0()(64bit) for package: pgadmin3_95-1.22.1-1.rhel7.x86_64
--> Processing Dependency: libwx_baseu_net-2.8.so.0()(64bit) for package: pgadmin3_95-1.22.1-1.rhel7.x86_64
--> Processing Dependency: libwx_baseu-2.8.so.0()(64bit) for package: pgadmin3_95-1.22.1-1.rhel7.x86_64
--> Running transaction check
---> Package wxBase.x86_64 0:2.8.12-20.el7 will be installed
---> Package wxGTK.x86_64 0:2.8.12-20.el7 will be installed
--> Processing Dependency: libSDL-1.2.so.0()(64bit) for package: wxGTK-2.8.12-20.el7.x86_64
--> Running transaction check
---> Package SDL.x86_64 0:1.2.15-14.el7 will be installed
--> Finished Dependency Resolution
Dependencies Resolved
========================================================================================
Package Arch Version Repository Size
========================================================================================
Installing:
pgadmin3_95 x86_64 1.22.1-1.rhel7 pgdg95 3.2 M
Installing for dependencies:
SDL x86_64 1.2.15-14.el7 base 204 k
wxBase x86_64 2.8.12-20.el7 epel 588 k
wxGTK x86_64 2.8.12-20.el7 epel 2.9 M
Transaction Summary
========================================================================================
Install 1 Package (+3 Dependent packages)
Total download size: 6.9 M
Installed size: 27 M
Is this ok [y/d/N]: y
Downloading packages:
(1/4): SDL-1.2.15-14.el7.x86_64.rpm | 204 kB 00:00:00
(2/4): wxBase-2.8.12-20.el7.x86_64.rpm | 588 kB 00:00:00
(3/4): wxGTK-2.8.12-20.el7.x86_64.rpm | 2.9 MB 00:00:01
(4/4): pgadmin3_95-1.22.1-1.rhel7.x86_64.rpm | 3.2 MB 00:00:48
----------------------------------------------------------------------------------------
Total 147 kB/s | 6.9 MB 00:48
Running transaction check
Running transaction test
Transaction test succeeded
Running transaction
Installing : wxBase-2.8.12-20.el7.x86_64 1/4
Installing : SDL-1.2.15-14.el7.x86_64 2/4
Installing : wxGTK-2.8.12-20.el7.x86_64 3/4
Installing : pgadmin3_95-1.22.1-1.rhel7.x86_64 4/4
Verifying : SDL-1.2.15-14.el7.x86_64 1/4
Verifying : wxGTK-2.8.12-20.el7.x86_64 2/4
Verifying : wxBase-2.8.12-20.el7.x86_64 3/4
Verifying : pgadmin3_95-1.22.1-1.rhel7.x86_64 4/4
Installed:
pgadmin3_95.x86_64 0:1.22.1-1.rhel7
Dependency Installed:
SDL.x86_64 0:1.2.15-14.el7 wxBase.x86_64 0:2.8.12-20.el7 wxGTK.x86_64 0:2.8.12-20.el7
Complete!安装pgAgent
yum install pgagent_95输入：
[root@localhost ~]# yum install pgagent_95
Loaded plugins: fastestmirror, langpacks
Loading mirror speeds from cached hostfile
* base: mirrors.163.com
* epel: mirrors.ustc.edu.cn
* extras: mirrors.163.com
* updates: mirrors.163.com
Resolving Dependencies
--> Running transaction check
---> Package pgagent_95.x86_64 0:3.4.0-9.rhel7 will be installed
--> Finished Dependency Resolution
Dependencies Resolved
========================================================================================
Package Arch Version Repository Size
========================================================================================
Installing:
pgagent_95 x86_64 3.4.0-9.rhel7 pgdg95 42 k
Transaction Summary
========================================================================================
Install 1 Package
Total download size: 42 k
Installed size: 151 k
Is this ok [y/d/N]: y
Downloading packages:
pgagent_95-3.4.0-9.rhel7.x86_64.rpm | 42 kB 00:00:02
Running transaction check
Running transaction test
Transaction test succeeded
Running transaction
Installing : pgagent_95-3.4.0-9.rhel7.x86_64 1/1
Verifying : pgagent_95-3.4.0-9.rhel7.x86_64 1/1
Installed:
pgagent_95.x86_64 0:3.4.0-9.rhel7
Complete!在数据库上配置pgAgent
找到pgagent.sql和pgagent_upgrade.sql文件路径，并在需要job功能的数据库上执行
将会在数据库中创建一个pgagent模式，并创建相应的功能表和函数
psql -U postgres
postgres=# \i /usr/share/pgagent_95-3.4.0/pgagent.sql
postgres=# \i /usr/share/pgagent_95-3.4.0/pgagent_upgrade.sql
postgres=# \q输入：
[root@localhost pgagent_95-3.4.0]# psql -U postgres
psql (9.5.9)
Type "help" for help.
postgres=# \i /usr/share/pgagent_95-3.4.0/pgagent.sql
BEGIN
CREATE SCHEMA
COMMENT
CREATE TABLE
COMMENT
CREATE TABLE
CREATE INDEX
COMMENT
INSERT 0 1
INSERT 0 1
INSERT 0 1
INSERT 0 1
INSERT 0 1
CREATE TABLE
COMMENT
COMMENT
CREATE TABLE
CREATE INDEX
COMMENT
COMMENT
COMMENT
CREATE TABLE
CREATE INDEX
COMMENT
CREATE TABLE
CREATE INDEX
CREATE INDEX
COMMENT
CREATE TABLE
CREATE INDEX
COMMENT
COMMENT
CREATE TABLE
CREATE INDEX
COMMENT
COMMENT
COMMENT
CREATE FUNCTION
CREATE FUNCTION
COMMENT
CREATE FUNCTION
COMMENT
CREATE FUNCTION
COMMENT
CREATE TRIGGER
COMMENT
CREATE FUNCTION
COMMENT
CREATE TRIGGER
COMMENT
CREATE FUNCTION
COMMENT
CREATE TRIGGER
COMMENT
COMMIT
postgres=# \i /usr/share/pgagent_95-3.4.0/pgagent_upgrade.sql
CREATE FUNCTION
CREATE FUNCTION
COMMENT
psql:/usr/share/pgagent_95-3.4.0/pgagent_upgrade.sql:49: ERROR: column "jstconnstr" of relation "pga_jobstep" already exists
ALTER TABLE
ALTER TABLE
postgres=# \q
如果数据库满足以下条件：
* PostgreSQL 版本高于9.1
* pgAgent 版本高于3.4.0
可使用简易安装模式：
[root@localhost pgagent_95-3.4.0]# psql -U postgres
psql (9.5.9)
Type "help" for help.
postgres=# CREATE EXTENSION pgagent;效果相同
启动pgAgent守护程序
语法：
pgagent_95 [options] <connect-string>
options:
-f run in the foreground (do not detach from the terminal)
-t <poll time interval in seconds (default 10)>
-r <retry period after connection abort in seconds (>=10, default 30)>
-s <log file (messages are logged to STDOUT if not specified>
-l <logging verbosity (ERROR=0, WARNING=1, DEBUG=2, default 0)>实例：
[root@localhost pgagent_95-3.4.0]# pgagent_95 hostaddr=192.168.230.134 dbname=postgres user=postgres password=oracle执行计划创建
使用pgadmin III工具连接目标库（可以使用其他机器远程连接目标库）
配置如下：
进入pgadmin后可看到作业状态，如下图所示：
创建作业date_delete_new
然后在date_delete_new作业中添加执行计划和步骤
创建计划delete_date_new
计划其实就是作业的执行时间表，可以在其中设置作业的运行时间，最小单位为min，设置方式与linux的cron控件类似
本次的业务要求是每月1号执行删除操作，顾只需设置每月一日执行即可：
新建计划：
设置日期为每月的1号
设置时间为00点00分
创建步骤delete_date_new
步骤是可以执行的SQL脚本或shell脚本，当计划条件触发时，作业的每个步骤将依次以字母数字名称顺序运行
本次的业务要求是删除表中一年以前的数据，以test表为例
新建步骤：
需要指定操作的数据库（postgres）
在定义中写入所要执行的脚本，如：
DELETE FROM "test"."test"
where time < CURRENT_DATE-('1 year')::INTERVAL;
到此执行计划创建完成