Question

Image making a Spring service, in the following manner:

+--------+           +---------+             +---------+
|Backend | --------- | My      | ----------- | Clients |
|service |           | service |             |         |
+--------+           +---------+             +---------+

In order not to make too much requests to the backend, I use Ehcache.
Imagine that my service is a sports portal, and I cache the results so that when a client requests them, I return the cache, if there’s no cache, I fetch the info from backend, put it in cache, and then return it to the client.

Now, If I have these parameters set

long timeToLiveSeconds
long timeToIdleSeconds

and the clients make requests too often, the timeToIdleSeconds won’t expire, but the timeToLiveSeconds will expire anyway and the element will be removed from the cache in which I’ve put it, right?

Answer 1

Yes, you are right.

For example:

timeToIdleSeconds = 30: if the cached object was not requested during that 30 seconds, it expires => last access time counts

timeToLiveSeconds = 60: after 60 seconds the cached object will expire – no matter how often it was requested or requested at all => creation time counts

From the docs (older version 1.4):

timeToIdleSeconds:
Sets the time to idle for an element before it expires.
i.e. The maximum amount of time between accesses before an element expires
Is only used if the element is not eternal.
Optional attribute. A value of 0 means that an Element can idle for infinity.
The default value is 0.

timeToLiveSeconds:
Sets the time to live for an element before it expires.
i.e. The maximum time between creation time and when an element expires.
Is only used if the element is not eternal.
Optional attribute. A value of 0 means that and Element can live for infinity.
The default value is 0.