rqdata被剥离后应该怎么改呢，这个rqdataclient现在是什么
database_manger现在是get_database，应该怎么改

可参考https://github.com/vnpy/vnpy/blob/dev/docs/database.md
https://github.com/vnpy/vnpy/blob/dev/docs/datafeed.md

在前面各位基础上更新VN2.9版本

from datetime import datetime
from vnpy.trader.constant import Exchange, Interval
from vnpy.trader.datafeed import get_datafeed
from vnpy.trader.object import HistoryRequest
from vnpy.trader.database import get_database

获取数据服务实例

database = get_database()
datafeed = get_datafeed()

updateInfo=[]
barOverViews=database.get_bar_overview()
for barOverView in barOverViews:

#print(f"{barOverView.symbol} start:{barOverView.start} end:{barOverView.end} count:{barOverView.count}")
updateInfo.append((barOverView.symbol,barOverView.exchange,barOverView.end,barOverView.interval))

endDt=datetime.now()

for info in updateInfo:
print(f'更新:{info[0]}，Interval:{info[3]}')
req=HistoryRequest(
symbol=info[0],
exchange=info[1],
start=info[2],
end=endDt,
interval=info[3],
)

获取k线历史数据

data = datafeed.query_bar_history(req)
#保存入数据库
database.save_bar_data(data)
print(f"{req.symbol}历史数据下载完成")