ASP.net Caching 初级问题。

澳贼

如何 让 Caching 在某一特定时间expire??

我们的新数据每天早上更新。

澳贼

乱码

你加一个dependency就好啊,不用设datetime,你具体看看它的api吧

Cache.Insert(key as String, value as Object, dependencies as CacheDependency, absoluteExpiration as DateTime, slidingExpiration as TimeSpan)

澳贼

http://msdn.microsoft.com/en-us/ ... itemremovedcallback(v=VS.90).aspx

想好了，只要算出时间就可以了。

原帖由 乱码 于 2011-1-7 11:34 发表
你加一个dependency就好啊,不用设datetime,你具体看看它的api吧

Cache.Insert(key as String, value as Object, dependencies as CacheDependency, absoluteExpiration as DateTime, slidingExpiration as TimeSpan ...

乱码

原帖由 澳贼 于 2011-1-7 11:40 发表
http://msdn.microsoft.com/en-us/ ... itemremovedcallback(v=VS.90).aspx

想好了，只要算出时间就可以了。

嗯，如果dependency太麻烦，这是最好的solution,skip掉date，只考虑hour/minute/sec就好.

澳贼

Cache.Insert("Key", GetObject(), null, DateTime.Today.AddHours(11.25d), Cache.NoSlidingExpiration, CacheItemPriority.Default,
                    new CacheItemRemovedCallback(RefreshCache));

dalaohu

If your app pool/service recycled, your screwed

if it has to be a specific time, do a windows service to purge the cache.

If u using appfabric, there are other meches doing that.

澳贼

“If your app pool/service recycled, your screwed” ？？ 大师你给解释解释。为什么我会被暴力性爱？？

原帖由 dalaohu 于 2011-1-7 17:18 发表
If your app pool/service recycled, your screwed

if it has to be a specific time, do a windows service to purge the cache.

If u using appfabric, there are other meches doing that.

澳贼

http://blogs.msdn.com/b/david.wa ... n-availability.aspx

David Wang 26 Jan 2006 9:24 PM #
Brian - Your intuition is on target; just missing some details. Let me explain...

Server applications, contrary to client applications, expect to run for a long period of time. Thus, a lot of server-side application employ caching to improve performance over time, at the expense of memory, for heavily used traffic patterns which may span across users.

For example, response to /default.aspx may be cached in memory such that after 1 user accesses it and pre-compile/caches it, the other 9 users immediately retrieves the URL without much processing. This is a huge performance win at the expense of spending memory to cache it.

In other words, the fact that after 10 users connect to an application, log off, and after half an hour the memory still remains used is insignificant. You have to accept that this may be the expected "working set" of your application.

What you should be concerned about is this -- suppose 10 users repeatedly log on/off and use the application over a period of time doing the same sort of thing and the memory used seems to increase without bound -- that is a sign of memory leak and must be addressed.

In other words, until you determine *through experimentation* the "working set" memory of that application, you cannot distinguish between "expected memory caching" (i.e. "working set") and "aggressive memory caching" (i.e. "memory leak"). And if you cannot distinguish between the two, arbitrary numbers like 160MB or invoking periodic recycling simply does not make sense.

It may be that for 10 users, your application's working set is 200MB after 1 hour and stays steady thereafter -- in which case you are prematurely worrying about nothing by looking at things in 30 minutes.

Sorry, there is no magic bullet nor calculation to automatically determine the proper metrics or need for recycling - it is all specific to the application and requires human experience to decide.

澳贼

dalaohu 能否回答问题？？？

混不到坑的萝卜

比如说你的cached objects依赖于某个服务器上的文件。每次你有新数据的时候就把那个文件更新一下，那么你的cache也会更新。
参考：
http://www.dotnetfunda.com/artic ... ncy-in-aspnet-.aspx

用sliding 或者 absolute expiration对你来说不够用么？sliding的话会有dalaohu说的问题，absolute不会。

澳贼

问题是数据源是sql server,不依赖于某个服务器上的文件。

我上面的例子就是用absolute time

原帖由 混不到坑的萝卜 于 2011-1-12 13:17 发表
比如说你的cached objects依赖于某个服务器上的文件。每次你有新数据的时候就把那个文件更新一下，那么你的cache也会更新。
参考：
http://www.dotnetfunda.com/artic ... th-file-dependency- ...