Mongodb TTL提前使文档过期 [英] Mongodb TTL expires documents early

问题描述

我正在尝试将文档插入到Mongo数据库中，并使其在预定时间后自动过期.到目前为止，即使我将'expireAfterSeconds'设置的时间更长，我的文档仍然可以插入，但总是在0-60秒内从数据库中删除.我知道mongodb大约每60秒就会删除过期的文档，因此'expredAfterSeconds'变量似乎无法正常工作.

I am trying insert a document into a Mongo database and have it automatically expire itself after a predetermine time. So far, my document get inserted but always get deleted from the database from 0 - 60 seconds even though I set the 'expireAfterSeconds' to much longer. I know mongodb deletes expired documents about every 60 seconds so it seems the 'expredAfterSeconds' variable is not working.

我在这里关注了文档: Mongodb TTL文档

I followed the documentation here: Mongodb TTL Docs

这是我的测试代码，应该在3分钟后过期(删除)文档(但它在一分钟内就会完成):

Here is my test code that should expire (delete) the document after 3 minutes (but it does it under a minute):

import pymongo
import datetime

mongo_con = pymongo.Connection('localhost', 27017)
mongo_db = mongo_con.Mongo_database
mongo_col = mongo_db.my_TTL_collection

timestamp = datetime.datetime.now()

mongo_col.ensure_index("date", expireAfterSeconds=3*60)                     

mongo_col.insert({'_id': 'login_session', "date": timestamp, "session": "test session"})

有人有什么想法吗?

推荐答案

您的问题来自在本地时区中使用朴素的时间戳. pymongo的常见问题解答有一个条目，其中包含一个警告，请不要使用datetime.datetime.now(). 使用utcnow，ttl设置可以按预期工作:

Your problems come from using naive timestamps in your local timezone. The FAQ of pymongo has an entry which includes a warning not to use datetime.datetime.now(). Using utcnow, the ttl-setting works as expected:

import pymongo
import datetime

mongo_con = pymongo.Connection('localhost', 27017)
mongo_db = mongo_con.Mongo_database
mongo_col = mongo_db.my_TTL_collection

timestamp = datetime.datetime.now()
utc_timestamp = datetime.datetime.utcnow()

mongo_col.ensure_index("date", expireAfterSeconds=3*60)                     

mongo_col.insert({'_id': 'session', "date": timestamp, "session": "test session"})
mongo_col.insert({'_id': 'utc_session', "date": utc_timestamp, "session": "test session"})
# the utc_session will be deleted after around 3 minutes, 
# the other depending on your timezone

这篇关于Mongodb TTL提前使文档过期的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！