PostgreSQL 引進“分割槽”表特性，解放了之前採用“表繼承”+ “觸發器”來實現分割槽表的繁瑣、低效。而新增分割槽，都是手動執行 SQL。

演示目的：利用 python 來為 PostgreSQL 的表自動新增分割槽。

python版本： python3+

pip3 install psycopg2

一、配置資料來源

database.ini 檔案：記錄資料庫連線引數

[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 指令碼

config.py 檔案：下面的config() 函式讀取database.ini檔案並返回連線引數。config() 函式位於config.py檔案中

#!/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、建立子表指令碼

pg_add_partition_table.py 檔案：其中 create_table函式是建立子表SQL。其中引數

引數名	含義
db	指向資料庫
table	主表
sub_table	正要新建的子表名
start_date	範圍分界開始值
end_date	範圍分界結束值

#!/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,(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、執行檔案main.py

main.py：主檔案；通過執行main生成分割槽表。

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

上面示例單獨為表tbl_game_android_step_log；建立分割槽；若多個表；用for語句處理

 # 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)

演示之後：

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')

五、加入定時任務

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