Sliding expiration

a. a at
Fri Apr 18 15:09:18 UTC 2008

Sliding expiration T means that every time an item is accessed it's  
"expiration counter" is reset, and only evicted if it was not accessed  
for T duration.

I.e. adding an item for 5 min sliding expiration means that it's  
evicted after 5 mins if no one accessed it. If the item is retrieved  
in that 5 min segment, the system will wait for another 5 mins before  
making it expired.


On Apr 18, 2008, at 4:45 PM, Michael Wieher wrote:
> Well, I'm not sure either, but some googling brough up a buncha msdn2
> / asp related things.... I sorta glanced and it seems like a FIFO
> idea, more or less, which brings up a question I have, although I have
> no idea if the original poster was wondering this but um
> time_t(0) when setting an object in the cache
> ....time passes....more objects get set....some time_t(0) some  
> time_t(n)...
> set-new-object time_t(0 or n) ... but cache is full...
> does it reject the new object
> or throw out the oldest time_t(0) object?
> or throw out the oldest time_t(n) object where n>0 but n-has-expired?
> if i wanted a pure FIFO cache, just set all expiration to NULL?
> On Fri, Apr 18, 2008 at 8:24 AM, Brian Moon <brianm at>  
> wrote:
>> Can you explain?  I am not sure what you mean by sliding.
>> Brian Moon
>> On Apr 18, 2008, at 1:56 AM, "Simone Busoli"  
>> <simone.busoli at>
>> wrote:
>>> Hello, I have a question about the expiration policy employed by
>> Memcached. Does it support sliding expiration out of the box or  
>> does it have
>> to be managed at the application level?

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