python 两个数据库postgresql对比

import psycopg2import sysclass 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 sizefrom information_schema.tablesorder 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 sizefrom information_schema.tablesorder 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_dicdef 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)