Backend can work with big uptime, but without gurantee stable durability - it can be restart from time to time + you must pay for full-day backend usage - from $1.2 per day for smallest backend class.
2011/11/21 Deepak Singh <[email protected]> > ok. So if i fetch these 6500 entities through a backend and set them to > cache for 8 days, will there be durability for 8 days? > > My app is low trafffic app and there might be time period when there is no > traffic to site setting instances to 0 for that time period. > > Thanks > Deepak > > > On Mon, Nov 21, 2011 at 9:20 PM, Jeff Schnitzer <[email protected]>wrote: > >> 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. >> > > > > -- > 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. > -- Blog: www.rekby.ru -- 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.
