Memcache doesn't work that way. You don't get any guaranteed quantity of cache and it's not guaranteed to last for any specific length of time - memcache is a shared resource and google allocates it according to their own magic algorithms.
Data falling out of the cache every 4-5 hours? That doesn't sound like a problem to me. If you have cache data that needs predictable durability, consider a backend. Jeff On Mon, Nov 21, 2011 at 10:59 AM, Deepak Singh <[email protected]>wrote: > My application while on loading makes a read operation around 6500 rows > which is fixed for app. I have set memcache for this feature with cache > expiration to 8 days. Bu i observe that cache usually fails 5 to 6 times in > day, so in that case my app has datastore read of around 6500 rows. Thus my > app heavily uses datastore read quota whic is very costly to me. > > I have been unable to make cache available for 8 days or even working > properly. > > It would be great if you can let me know how to optmize this cache > properly. > > Thanks > Deepak > > > On Mon, Nov 21, 2011 at 4:14 AM, Brandon Wirtz <[email protected]>wrote: > >> Memcache is just a cache. Your values have no guarantee of being there >> even >> 1micro second after you did the write. >> >> If you post your code we might be able to help, but I assure you Memcache >> does work. >> >> My app does reads from the datastore or memcache for every request, >> sometimes to for initialization of variables... like Who am I, Why am I >> here, what configuration am I in. And then to serve the request... >> >> We use a combination of instance memory and memcache to not have to talk >> to >> the data store. Datastore reads are "slow" compared to Instance Memory and >> Memcache. >> >> Datastore Write Operations 0.24 Million Ops 0.19 >> $1.00/ Million Ops $0.19 >> Datastore Read Operations 0.02 Million Ops 0.00 >> $0.70/ Million Ops $0.00 >> >> >> I didn't count the "reads in my app" to the "writes" but I know I do reads >> for initialization every time, and reads for data every time. I only do >> writes on some requests... So I am going to be conservative and say >> that I >> do 3x as many reads as writes in my code, but so far today I have hit the >> Datastore with a write 10x as many times as I have a read. That works out >> to my local memory and memcache saving me 97% of the time. >> >> I don't have an easy way to tell you how much of the time that is instance >> memory and how many times it is memcache, but I assure you it works. >> >> >> >> -----Original Message----- >> From: [email protected] >> [mailto:[email protected]] On Behalf Of Jamil Rzayev >> Sent: Sunday, November 20, 2011 1:48 PM >> To: Google App Engine >> Subject: [google-appengine] Memcache doesn't work >> >> Hi. >> >> I have to use memcache to store some values frequently accessible by >> application I am working on. >> The Google App Engine Memcache doesn't work as it apparently removes >> values >> after a couple of minutes I store it at memcache. >> >> I really need any idea and would highly appreciate for any comments. >> I have already tried to ask here, but got response that I need to store >> values as soon as I read them and didn't work. >> >> I am still losing my values... >> >> -- >> 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. >> >> >> -- >> 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. >> >> > > > -- > Deepak Singh > > -- > 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. > -- I am the 20% -- 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.
