CODEWITHSUNDEEP
cakephprediscakephp-2.0
Greg Motyl
Greg Motyl

Reputation: 2555

Redis for cakePHP app

I want to start a big cakePHP project where performance will be an issue. I will have a users table with act as tree behavior and many financial data related to the users. This application will make a lot of dynamic reports aggregating data for different tree nodes etc.

Since there is on github an easy to use library which sets data source of model to redis, I was wondering if it's a good idea to use it for entire app? Is there anyone who has experience with it, and what could be potential problems if I decide to depend on redis as main/only data storage?

EDIT: I have installed redis and Tried to use RedisModel for two models with simple relation HasMany/BelongsTo. When I tried to simply use those models like standard AppModels - it simply wont work (Redis Error: Missing key). Apparently you can't use Model->find Model->save etc. in standard way. You have to use redis methods instead (setKeyValue ect.). This means that pagination and other cakePHP futures will also not work. So maybe it is not the best idea to use redisModel for all my models...

Upvotes: 3

Views: 1802

Answers (1)

Mahn
Mahn

Reputation: 16605

I cannot speak for CakePHP specifically, but I'll talk about redis in general and the points of your question in particular, it should be applicable to your framework of choice in the end. Let's see:

  • You mention you want to start an application where performance will be an issue — I just wanted to mention you should be careful with the assumption that you will need a nosql solution, because this is hard to assess beforehand. Redis is hella fast, but MySQL for instance has been proven to be capable to handling millions of records and operations just fine, provided it's properly configured and used, and it's much simpler if you need lots of relational structures.

  • Concerning Redis as the main and only data store:

    • Redis is perfectly stable for the job. Instagram reportedly stored 300 million key-value pairs pseudo-sharded using hashes to great effect, and while it's not the only data storage system they use, it goes to show redis is pretty reliable. This very site (Stack Overflow) uses redis also extensively for caching purposes.

    • Redis is also reported to have an overall excellent continuous uptime on average (which shouldn't be surprising considering the point above)

    • Options exists to mitigate downtime issues, replication is supported to some extent, and Redis Cluster is coming soon to support proper distributed approaches.

    • The main problem you could face is not understanding properly how its persistence works. You should absolutely read this and this article before you get started because this point is important. In a nutshell, redis does not write changes immediately to disk, which means that depending on your configuration, a crash can cause a data loss ranging from a few seconds to several minutes since the last disk write. This might or might not be a problem depending on your use case; if the data is extremely sensitive (ie, financial records) you might want to think twice before jumping to redis, or build a system where redis is not exclusively used but rather combined with another storage system.

  • Relational structures in a non-relational data store like redis mean doing more work and often duplicating/denormalizing data. It can be done, but it's something to consider; in your question you mention you'll need to aggregate data to generate dynamic reports, are you sure you want to use redis for this? it sounds like a relational database would give you way more flexibility at a very small cost of performance. If you know in advance you'll need to run complex queries over your data, it could be a good idea not to reinvent the wheel unless you absolutely need to.

My advice here would be to first get a better feeling on what redis is and how works, potentially build your own models instead of relying on others to better understand what can and cannot be done, and from there assess where you want to take it. Redis is reliable enough to be used standalone, but at the end of the day what's smart is to use the right tool for the right job, and you might find some things of your app work well with redis while some others are better off to a more traditional storage system.

Upvotes: 5

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