Thanks for the information.
So the expiration time is only a maximum time to be stored in the
cache, not an explicit time that you want it to stay.
If you don't specify an expiration time -- is that like setting an
expiration time of infinity, or is there a default? I'm trying to
maximize the amount of time that the item stays in the cache.
On Feb 26, 9:46 am, Barry Hunter wrote:
> Set the time for as long as you can acceptably use cached data. (days
> if you can)
>
> Just dont expect it to be there all the time, AppEngine can and will
> evict the cache as it needs the memory.
>
> Actual retention is based more on usage of the data rather sticking to
> the expiration time. So data that gets used more will hang around
> longer (upto its expiration time) than rarely used data. (on the basis
> that data that is getting read lots is actully the most useful - its
> saved more hits on the origin datasource)
>
> On 26 February 2010 13:51, xcdesz wrote:
>
> > Thanks -- that is useful to know. Do you know if there is a maximum
> > expiration time -- for example, if I set expiration to something like
> > 4-8 hours, would that be a bad practice?
>
> > On Feb 26, 4:29 am, Barry Hunter wrote:
> >> According to the Documentantion theJCacheimplementation is just a
> >> wrapper around memcache
>
> >>http://code.google.com/appengine/docs/java/memcache/
>
> >> With memcache you explicitly set the expiration time you want on how
> >> long the data should survive for.
>
> >> The 'memory' is actually distributed and lives outside the JVM, so is
> >> shared by all instances (if you have multiple running), and does
> >> survive JVM restarts.
>
> >> On 25 February 2010 20:49, xcdesz wrote:
>
> >> > I am confused about howJCacheworks with Google's cloud, and have
> >> > some basic questions that I havent been able to find answers for..
>
> >> > Suppose I am usingJCacheto store query results (i.e; a list of blog
> >> > postings), so that users do not have to hit the datastore when
> >> > initially logging on to a site. If I have a low-traffic situation,
> >> > where one user logs in and logs out after a few minutes, and another
> >> > user might not log on for another hour or so -- do those query results
> >> > stay inJCachelong enough for the other user to see the cached
> >> > results of the previous user?
>
> >> > I'm trying to reduce the "loading request" time by using cached
> >> > results instead of the datastore. Is this possible, or does the
> >> >JCacheinstance (and JVM, for that matter) die pretty quickly after
> >> > inactivity. DoesJCachelive and die with the JVM -- or is it
> >> > somewhere else?
>
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