Hi, I am new to Rails and I am building a rails server which acts as the backend for a mobile app. I have certain daemon processes that fetch and store data in a database. Every time someone makes a request for data from the phone, I will have to send him the same dataset irrespective of who is requesting the data. This dataset will keep changing quite frequently and my daemons will keep updating the database accordingly. Since the same data is to be sent to every one, I am assuming that it would be best to cache the data on the server and keep updating the cache at a set frequency (thus making only one trip to the db). When I get a request from the phone, I just retrieve this cached dataset and send it back, w/o hitting the db. I think one way of doing this would be to use a singleton model class which will cache the data and this would act as the source. Is this the best way to go about this process? Does Rails provide some other means of doing this? Thanks, Ramkumar.
on 2011-02-22 10:33
on 2011-02-22 11:01
On Feb 22, 9:33am, Ram Kumar <li...@ruby-forum.com> wrote: > sent to every one, I am assuming that it would be best to cache the data > on the server and keep updating the cache at a set frequency (thus > making only one trip to the db). When I get a request from the phone, I > just retrieve this cached dataset and send it back, w/o hitting the db. > > I think one way of doing this would be to use a singleton model class > which will cache the data and this would act as the source. Is this the > best way to go about this process? Does Rails provide some other means > of doing this? Rails provides Rails.cache which is an abstraction round several different data stores. Personally i wouldn't usually recommend the in memory cache you're considering. It means that you have as many copies of the data in memories as you have mongrels/passenger instances etc, ie you are fetching the data more often than you need. It also makes it difficult for you to force expiry of the cache. Most people use something like memcache for this job (one of the cache stores Rails.cache supports is a memcache store). You may also want to consider caching at different levels in the stack, for example by putting something like varnish in front of your web servers. Fred
on 2011-02-22 11:09
Regarding the daemon part of your application, I've done something similar before, and used a combination of Rails-based rake tasks triggered by Chronic or something similar. I didn't have the need to manage the cache as you're describing, but including a task that refreshes cached information and running it after each update would probably be simple enough. On Tue, Feb 22, 2011 at 10:59 AM, Frederick Cheung <
on 2011-02-23 12:15
Hi, First off thank you both for your replies and apologies for the delayed reply. @Fred: I don't know about passenger/ multiple mongrel instances yet and will look that up. I will also explore Rails:Cache and see what I can come up. @Chris: I was going to do some cron jobs which send requests to the server. Rake tasks seems to be a much better way. I will explore that too. Once again thanks for your help in pointing me in the right direction. Ram.