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 <[email protected]> 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 <[email protected]> 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 <[email protected]> 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 <[email protected]> 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? > > >> > -- > >> > You received this message because you are subscribed to the Google > >> > Groups "Google App Engine" group. > >> > To post to this group, send email to [email protected]. > >> > To unsubscribe from this group, send email to > >> > [email protected]. > >> > For more options, visit this group > >> > athttp://groups.google.com/group/google-appengine?hl=en. > > > -- > > You received this message because you are subscribed to the Google Groups > > "Google App Engine" group. > > To post to this group, send email to [email protected]. > > To unsubscribe from this group, send email to > > [email protected]. > > For more options, visit this group > > athttp://groups.google.com/group/google-appengine?hl=en. -- You received this message because you are subscribed to the Google Groups "Google App Engine" group. To post to this group, send email to [email protected]. To unsubscribe from this group, send email to [email protected]. For more options, visit this group at http://groups.google.com/group/google-appengine?hl=en.
