利用python为PostgreSQL的表自动添加分区

PostgreSQL引进“分区”表特性，解放了之前采用“表继承”+“触发器”来实现分区表的繁琐、低效。而添加分区，都是手动执行SQL。

演示目的：利用python来为PostgreSQL的表自动添加分区。
python版本：python3+

pip3 install psycopg2

一、配置数据源

database.ini 文件：记录数据库连接参数

[adsas]
host=192.168.1.201
database=adsas
user=adsas
password=adsas123
port=5432

[test]
host=192.168.1.202
database=adsas
user=adsas
password=adsas123
port=5432

二、config 脚本

config.py 文件：下面的 config() 函数读取 database.ini 文件并返回连接参数。config() 函数位于config.py文件中

#!/usr/bin/python3
from configparser import ConfigParser

def config(section ,filename='database.ini'):
 # create a parser
 parser = ConfigParser()
 # read config file
 parser.read(filename)

# get section, default to postgresql
 db = {}
 if parser.has_section(section):
   params = parser.items(section)
   for param in params:
     db[param[0]] = param[1]
 else:
   raise Exception('Section {0} not found in the {1} file'.format(section, filename))

return db

三、创建子表脚本

pg_add_partition_table.py 文件：其中 create_table函数是创建子表SQL。其中参数

#!/usr/bin/python3

import psycopg2
from config import config

#example: create table tbl_game_android_step_log_2021_07 PARTITION OF tbl_game_android_step_log FOR VALUES FROM ('2021-07-01') TO ('2021-08-01');
def create_table(db, table, sub_table, start_date, end_date):
 """ create subtable in the PostgreSQL database"""
 command = "create table {0} PARTITION OF {1} FOR VALUES FROM ('{2[0]}') TO ('{2[1]}');".format(sub_table, table, (start_date, end_date))
 conn = None
 try:
   # read the connection parameters
   params = config(section = db)
   # connect to the PostgreSQL server
   conn = psycopg2.connect(**params)
   cur = conn.cursor()
   # create table one by one
   cur.execute(command)
   # close communication with the PostgreSQL database server
   cur.close()
   # commit the changes
   conn.commit()
 except (Exception, psycopg2.DatabaseError) as error:
   print(error)
 finally:
   if conn is not None:
     conn.close()

四、执行文件main.py

main.py：主文件；通过执行main生成分区表。

示例：

#!/usr/bin/python3
import datetime
from datetime import date
from dateutil.relativedelta import *
from pg_add_partition_table import create_table

#Get the 1st day of the next month
def get_next_month_first_day(d):
 return date(d.year + (d.month == 12), d.month == 12 or d.month + 1 , 1)

def create_sub_table(db, table):
 # Get current date
 d1 = date.today()
 # Get next month's date
 d2 = d1 + relativedelta(months=+1)
 # Get the 1st day of the next month;As the starting value of the partitioned table
 start_date = get_next_month_first_day(d1)
 # Gets the 1st of the next two months as the end value of the partitioned table
 end_date = get_next_month_first_day(d2)
 # get sub table name
 getmonth = datetime.datetime.strftime(d2, '％Y_％m')
 sub_table = table + '_' + getmonth
 create_table(db, table, sub_table, start_date, end_date)

if __name__ == '__main__':
 create_sub_table('test', 'tbl_game_android_step_log');

上面示例单独为表tbl_game_android_step_log；创建分区；若多个表；用for语句处理

# 多表操作

for table in ['tbl_game_android_step_log', 'tbl_game_android_game_log','tbl_game_android_pay_log']:
   create_sub_table('test', table);
演示之前：
adsas=> select * from pg_partition_tree('tbl_game_android_step_log');
       relid        |    parentrelid    | isleaf | level
-----------------------------------+---------------------------+--------+-------
tbl_game_android_step_log     |              | f   |   0
tbl_game_android_step_log_2020_12 | tbl_game_android_step_log | t   |   1
(2 rows)

演示之后：

adsas=> select * from pg_partition_tree('tbl_game_android_step_log');
       relid        |    parentrelid    | isleaf | level
-----------------------------------+---------------------------+--------+-------
tbl_game_android_step_log     |              | f   |   0
tbl_game_android_step_log_2020_12 | tbl_game_android_step_log | t   |   1
tbl_game_android_step_log_2021_01 | tbl_game_android_step_log | t   |   1

Partition key: RANGE (visit_time)
Partitions: tbl_game_android_step_log_2020_12 FOR VALUES FROM ('2020-12-01 00:00:00') TO ('2021-01-01 00:00:00'),
     tbl_game_android_step_log_2021_01 FOR VALUES FROM ('2021-01-01 00:00:00') TO ('2021-02-01 00:00:00')

来源：https://blog.csdn.net/weixin_46199817/article/details/112261389