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Comment by brianwawok | Hacker News Reader

How do you do it with a load balanced stateless web server? People have been doing this 10 years, most language should have some frameworks or plugins around it....

Common is to give the client a cookie with a session id (KJASDJKASDASDS) in a cookie. Then in a RDBMS you store this (session KJASDJKASDASDS = User 1234)... and the first part of each web (or lambda call), you go look up the user by session and know who it is.

(You can also store the user ID directly in an encrypted cookie, but that has a few other problems)

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Thanks for the reply. In which DB should I store this data, considering the option of either DynamoDB or ElastiCache?

Why not MySQL or PostgreSQL? Any reason you can't be relational?

Because I don't want to manage my own DB, so I would rather stick with the options that Amazon offers as a service.

You realized Amazon offers hosted MySQL and PostgreSQL, right? One click, and it's up.

https://aws.amazon.com/rds/

Ok, I want a 2 pronged approach:

1) A NoSQL DB for the main data providing replication and scalability(e.g. Cassandra or DynamoDB).

2) Another DB for quick access and transient Data where replication is not so important, e.g. storing the session cookie. Relational vs Non-relational would not be an issue since I'm only storing very little data here and want fast access and minimize costs(in DynamoDB you still have to pay per operation). Therefore I'm looking for some simple solution like ElastiCache.

How much data are you going to have, and of what format? Do you actually need NoSQL here?

I'm doing a social networking site, so I don't know how much data I will end up with. My reasoning was as follows:

1) The data model is rather simple, basically one table with the user data(name, location, age, etc...) and some images. So it shouldn't be too difficult to do this with NoSql as opposed to SQL. Yes, simpler with SQL but not significantly so.

2) If I ever need to scale, I'd rather make the right choice from the beginning(NoSQL) so as not to need a migration later.

3) In any case NoSQL would be a learning experience for me, so another plus.

If there is a mistake in my reasoning I would be grateful for any one pointing it out.

Just curious, what would be the major drawbacks of not using relational here? My understanding is that AWS is pushing Dynamo quite a bit and it seems cheaper, so if they're only needing to query off of session id and maybe user id, shouldn't that be sufficient?

Relational is super handy. Very easy to report on and do various things down the road.

If all he needed was session id, sure, NoSQL is more or less the same. But what about when he adds other fields that are related? Say customer address or reports or .... His life may very well be easier with relational.

You should generally start relational. Then branch out if you are hitting the brick walls of relational. People using NoSQL for a 100MB database are making their life SERIOUSLY more difficult than it needs to be. (I have done it before, not fun).

> You should generally start relational.

I don't know if it is that easy to scale once you realize that the demand is growing, see my other reply here:

https://news.ycombinator.com/item?id=12692234

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