python 两个数据库postgresql对比

这篇文章主要介绍了python 两个数据库postgresql对比,文中通过示例代码介绍的非常详细，对大家的学习或者工作具有一定的参考学习价值,需要的朋友可以参考下

比较两个postgresql数据库，原理 比较数据库中各表的大小

1. 数据库查询语句

2. python字典比较

import psycopg2
import sys

class PdbModel:
 def __init__(self, host, dbname, username='postgres', password='postgres', port='5432'):
   self.host = host
   self.dbname = dbname
   self.username = username
   self.password = password
   self.port = port

self.conn = None
   self.cursor = None
   self.init_db()

def init_db(self):
   try:
     self.conn = psycopg2.connect(database=self.dbname, user=self.username, password=self.password,
                    host=self.host,
                    port="5432")
     self.cursor = self.conn.cursor()

except Exception, e:
     error_out_print("Error: connection to db ％s : ％s failed. check need" ％ (self.host, self.dbname))
     print e
     sys.exit(-1)

def execute_sql(self, sql, is_exist=True):
   """
     execute sql and return rows
   :param sql:
   :return:
     results of execute sql
   """
   try:
     standout_print('command sql : ％s' ％ sql)
     self.cursor.execute(sql)
     rows = self.cursor.fetchall()
     return rows

except Exception, e:
     self.conn.rollback()
     error_out_print("Failed: failed execute sql [％s]" ％ sql)
     error_out_print(e)
     if is_exist:
       self.close()
       sys.exit(-1)
     else:
       return None

def get_tables_size(self):
   """
   select table_schema || '.' || table_name as table_full_name , pg_size_pretty(pg_total_relation_size('"'||table_schema||'"."'||table_name||'"')) as size
from information_schema.tables
order by pg_total_relation_size('"'||table_schema||'"."'||table_name||'"') DESC

:return:
   """
   standout_print("get the size of tables in db [％s]." ％ self.dbname)
   sql = """
   select table_schema || '.' || table_name as table_full_name , pg_size_pretty(pg_total_relation_size('"'||table_schema||'"."'||table_name||'"')) as size
from information_schema.tables
order by pg_total_relation_size('"'||table_schema||'"."'||table_name||'"') DESC
   """
   rows = self.execute_sql(sql)
   table_size_dic = {}
   for row in rows:
     table_name = row[0]
     table_size = row[1]
     table_size_dic[table_name] = table_size
   return table_size_dic

def standout_print(info):
 sys.stdout.write("Info: ％s " ％ info)
 sys.stdout.flush()

def error_out_print(info):
 sys.stderr.write("Error: ％s " ％ info)
 sys.stderr.flush()

if __name__ == '__main__':
 db1 = ''
 db2 = ''
 host = "172.16.101.92"
 db_model1 = PdbModel(host, db1)
 db_model2 = PdbModel(host, db2)
 table_size_dic1 = db_model1.get_tables_size()
 table_size_dic2 = db_model2.get_tables_size()
 import pprint

# pprint.pprint(table_size_dic1)
 # pprint.pprint(table_size_dic2)
 print cmp(table_size_dic1, table_size_dic2)
 is_equal = cmp(table_size_dic1, table_size_dic2)
 different_table_size_dic = {}
 if is_equal == 0:
   print "these tables in two database are same."
 else:
   keys1 = table_size_dic1.keys()
   keys2 = table_size_dic2.keys()

for key in keys1:
     value1 = table_size_dic1.get(key)
     value2 = table_size_dic2.get(key)
     if cmp(value1, value2) != 0:
       different_table_size_dic[key] = (value1,value2)

pprint.pprint(different_table_size_dic)

来源：https://www.cnblogs.com/dasheng-maritime/p/7676557.html