Building a MongoDB Clone in Postgres

Post by masklinn » Tue, Jun 05, 2012, 5:07 PM UTC

bad_user wrote: post #88

hobb0001 wrote: post #85

Earlier quoted context omitted.

Since the relational model is very set-oriented, it has always had a particularly hard time dealing with ordered lists. But that's really a minor thing, and is actually something an ORM can do well to abstract. My real headache with ORM has always been to get it to perform efficiently. For example, say I want to iterate through the GPA's of all the students. To do so, the ORM usually pulls in the full object model fo…

I've used ORM tools such as the one in Django, Active::Record and DBIx::Class. I do not have the issues you mentioned ... I always remember the API calls I need to make and performance has not been an issue (granted, I'm fairly familiar with all issues that can come up, so I know when or where to optimize in general). the ORM usually pulls in the full object model for each student Here's how to do it in Django (and n…

    for student in Student.objects.only('gpa'):
        print student.gpa

Post by abarales » Tue, Jun 05, 2012, 10:29 PM UTC

Post by leothekim » Wed, Jun 06, 2012, 12:46 AM UTC

moe wrote: post #94

leothekim wrote: post #92

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I don't think what I said was bullshit. So you wrote tests to make mongo fail, and you've seen cases where people run into problems with it. That still doesn't disprove my point. With postgres, you roll your own sharding. With mongo, you don't have to.

Sure, makes sense. If you're happy with your deployment randomly failing.

Post by jshen » Wed, Jun 06, 2012, 7:55 PM UTC

moe wrote: post #84

nsanch wrote: post #74

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[1] looks like an example where the data didn't fit in RAM. Mongo works best when data fits in RAM or if you use SSD's. Yes, it's sub-optimal. [2] is from a year and a half ago. It doesn't belong in a sentence that includes the word "still." I work at foursquare, btw. Those outages happened on my first and second days at the company. I wasn't so keen on mongo then either. We've gotten much better at administering it.…

[2] When you look at [1] you'll notice that these exact problems are still prevalent. I'd in fact be curious how exactly did you work around the sharding issues at 4square? Remember I replied to someone who claimed it takes "no engineering effort" to scale MongoDB. That's not only obviously false, but last time I tried the sharding was so brittle that recommending it as a scaling path would border on malice. I ran a…

Post by vampirechicken » Fri, Jun 15, 2012, 4:23 PM UTC

einhverfr wrote: post #68

vampirechicken wrote: post #62

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> SQL still has a place and MongoDB is no replacement Let's flip this: NoSQL is finding it's place in the database ecosystem. SQL is the name of a database query language, NoSQL is a term that identifies a set of new, ostensibly non-relational, data storage engines that so implement an SQL parser despite SQL being the Standard Query Language, with twenty years of history behind it. My opinion - They decided to call i…

"I'd much rather access data from Mongo, Riak, Redis, and Couch using the SELECT, INSERT, UPDATE and DELETE statements that I have known since 1988, instead of having to learn four new database APIs." Doesn't work because those are set operations which are meaningless outside the relational world. If you want to use set operations, use a relational database.