Ch. 15 (p. 571)

Tulsi · January 11th, 2013, 01:19 AM

Hi Imar,

If user #1 is caching a review and another user (user #2) makes an update to it, how will user #1 know that an update was made? Will the update made by user #2 invalidate the review that's cached for user #1?

Thanks.
Tulsi

Imar · January 11th, 2013, 03:41 AM

Hi Tulsi,

It depends; if you use the data-source controls with caching enabled on a page to display and edit them, .NET takes care of this. Otherwise, yes, you run into "stale data". if you're doing everything in code you can easily remove the edited item from the cache when you're done saving the changes. Alternatively, when using the data controls, you can handle an Edited event and then update or clear the cache.

Finally, if it's acceptable, you can just wait, if the cache time is short enough. The new item will appear automatically after the old one has expired.

Hope this helps,

Imar

Tulsi · January 17th, 2013, 03:10 PM

Hi Imar,

Thank you for the explanation, but I guess I'm still a little confused as to how the caching works.

Is there one common cache for all users or is there a cache setup for each user?

Thank you.
Tulsi

Imar · January 18th, 2013, 06:48 AM

It applies to the entire application, and thus to all users. It's a big bag that can hold all kinds of stuff referred to by a key. In addition, it has behavior to eject items from the cache based on logic (expire date, changed dependencies etc.)

Cheers,

Imar