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Goodbye MongoDB, Hello PostgreSQL

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Re: Goodbye MongoDB, Hello PostgreSQL

#61

Post by masklinn »

jgrahamc wrote: post #35
Pxtl wrote: post #27

Earlier quoted context omitted.

I use Entity Framework as an ORM and I have to say I like it. As much as there have been a lot of false-starts related to trying to reinvent SQL, I think Entity Framework hits many of the right notes for me: 1) All my code lives in Visual Studio with compile-time type-checking. No maintaining stored procedures outside of my main codebase, no mucking about with strings. And because Entity Framework puts the Select aft…

Yes. I pretty much agree with you and am happy for people to use ORMs (or raw SQL if that's their thing and they are into maintaining it). It's actually the underlying 'throw away all this old SQL database stuff' that is the biggest loss for people because they miss out on the power and optimization that's gone into those databases.

But doesn't the Sequel snippet just write SQL as Ruby and get Ruby objects out? It's still pretty raw SQL, just not SQL-as-embedded-strings-guess-the-syntax-error. And surely it's easier to extract, compose or otherwise manipulate reified queries than by concatenating floating bits of strings.

Re: Goodbye MongoDB, Hello PostgreSQL

#62

Post by pdeuchler »

jgrahamc wrote: post #13

As a greying developer I am most amused by people discovering that 'old' technologies like SQL databases work really well. The only useful piece of advice I can give a younger developer is... be careful when drinking the newtech koolaid. And one more thing: star = Sequel.lit('*') User.select(:locale) .select_append { count(star).as(:amount) } .select_append { ((count(star) / sum(count(star)).over) * 100.0).as(:percen…

sigh

Not this argument again. I'm all for learning SQL (just like one should always learn foundational concepts), but for some reason there's this notion popping up that Real Programmers use Raw SQL, just like 20 years ago Real Programmers used Assembly. For the love of God, stop hating on basic software engineering principles like code-reuse and allow us to move up the abstraction hierarchy like we do in literally every other facet of software development. Here's a comment I made on the issue of ORMs vs Raw SQL a while back that goes into more detail: https://news.ycombinator.com/item?id=8134205

In the past year I've also grown very fond of type safety within my ORM coding as well, something that's hard to achieve at compile time with just raw SQL.

Re: Goodbye MongoDB, Hello PostgreSQL

#63

Post by misiti3780 »

super_sloth wrote: post #2

Is there anybody here who has run MongoDB at moderate scale with good results? As in a few terabytes of data, >10k ops/second territory. I've been really disappointed with its reliability and performance in situations where I've been around that.

i think foursquare is, unless they have migrated off and did not publicized it

Re: Goodbye MongoDB, Hello PostgreSQL

#64

Post by chousuke »

jgrahamc wrote: post #13

As a greying developer I am most amused by people discovering that 'old' technologies like SQL databases work really well. The only useful piece of advice I can give a younger developer is... be careful when drinking the newtech koolaid. And one more thing: star = Sequel.lit('*') User.select(:locale) .select_append { count(star).as(:amount) } .select_append { ((count(star) / sum(count(star)).over) * 100.0).as(:percen…

I may just be rehashing sibling arguments here, but to me that particular API looks very much what I think an SQL-wrapping library ought to be: a replacement for string concatenation and something that allows you to treat SQL queries as data. I don't know anything about Sequel, but that example still feels close enough to SQL.

My experience with ORMs has been that I eventually end up regretting using one if I try to model my data as objects because with ORMs it's easy to code yourself into a corner where you end up wishing that your design supported the relational model instead.

I do understand the desire for a good ORM, though. SQL is extremely powerful and a well-designed database is a joy to work with, but a sequence of tuples is often not the most convenient datastructure to process in most programming languages.

Re: Goodbye MongoDB, Hello PostgreSQL

#65

Post by matthewmacleod »

bau5 wrote: post #57
limelight wrote: post #44

This post reflects an interesting technical narrative of companies switching off MongoDB to more traditional relational databases as they grow. Importantly, I don't think that's an indictment of MongoDB. Instead, it highlights the key advantages of NoSQL: ease of use and rapid iteration. When you're first working on a project, MongoDB is very easy to slap in. You don't even have to create tables/collections. As you i…

No, this is bad. You shouldn't design a system that won't work from the outset. "Plan one to throw away" is about budgeting time, not about knowingly making big technical compromises when you write the first version.

But these systems do work - it's just that they don't necessarily scal as well as others.

It's silly to expect that every single software project requires the same level of correctness or maintainability. A rapidly-developed speculative SaaS for example may be able to trade long-term maintainability or scalability for faster development time (often more important if you have no idea whether or not your idea will even work).

Re: Goodbye MongoDB, Hello PostgreSQL

#66

Post by JonnieCache »

jonahx wrote: post #59
JonnieCache wrote: post #24

Earlier quoted context omitted.

Sequel is the best ORM I've ever seen or used, but that is (probably IMO) not a good application of it. It gives you total choice over what level of abstraction you want, so this is a particularly egregious use of it, being as nothing about that query is dynamic :) You can use it purely to execute handwritten SQL queries loaded from files, or stored procedures, or any level of abstraction between raw SQL and the mons…

jeremy is incredible. he is more helpful and available (and certainly more knowledgeable) than most paid support people for premium products. if you are learning sequel, stop by the irc channel and he'll probably answer your question.

seriously the man is a hero. I owe him about a brewerys worth of drinks.

EDIT: I just went to look at the github: 1821 stars, zero issues. And yes, github is the projects official bug tracker. There are 662 closed issues.

I must see if I can arrange for work to send him some money...

Re: Goodbye MongoDB, Hello PostgreSQL

#67

Post by jjtheblunt »

jgrahamc wrote: post #13

As a greying developer I am most amused by people discovering that 'old' technologies like SQL databases work really well. The only useful piece of advice I can give a younger developer is... be careful when drinking the newtech koolaid. And one more thing: star = Sequel.lit('*') User.select(:locale) .select_append { count(star).as(:amount) } .select_append { ((count(star) / sum(count(star)).over) * 100.0).as(:percen…

Agreed. And one might note that there's a really good reason Oracle has dominated for decades, and Larry Ellison (who read the SQL research paper, and formed a company to implement it nearing 40 years ago) is a billionaire.

Re: Goodbye MongoDB, Hello PostgreSQL

#68

Post by chc »

ttty wrote: post #32
jgrahamc wrote: post #13

As a greying developer I am most amused by people discovering that 'old' technologies like SQL databases work really well. The only useful piece of advice I can give a younger developer is... be careful when drinking the newtech koolaid. And one more thing: star = Sequel.lit('*') User.select(:locale) .select_append { count(star).as(:amount) } .select_append { ((count(star) / sum(count(star)).over) * 100.0).as(:percen…

I sincerely still prefer mongodb syntax because: - Fits well with a programming language; {a: data.x} is better than 'WHERE A="' + data.x + '"' (sanitize?) or similar which are harder to read. SQL queries are good for direct input, mongodb queries styles are better to be used with a programming language;

That is not how you do parameterized queries. With any civilized database library, it would be something along the lines of `"WHERE a = ? AND b = ?", data.x, data.y`, so that the parameters are like function parameters.

Re: Goodbye MongoDB, Hello PostgreSQL

#69

Post by YorickPeterse »

MaggieL wrote: post #45
limelight wrote: post #44

This post reflects an interesting technical narrative of companies switching off MongoDB to more traditional relational databases as they grow. Importantly, I don't think that's an indictment of MongoDB. Instead, it highlights the key advantages of NoSQL: ease of use and rapid iteration. When you're first working on a project, MongoDB is very easy to slap in. You don't even have to create tables/collections. As you i…

OP will be back in three years talking about migrating off of Ruby...if they make it that far :-)

Unlikely, we've been running on Ruby for about 5 years and it's the one thing we feel safe relying on for our serious internet business. Actually, our entire setup is Ruby (safe from some shell scripts here and there).

Re: Goodbye MongoDB, Hello PostgreSQL

#70

Post by masklinn »

aethertap wrote: post #48
ttty wrote: post #32

Earlier quoted context omitted.

I sincerely still prefer mongodb syntax because: - Fits well with a programming language; {a: data.x} is better than 'WHERE A="' + data.x + '"' (sanitize?) or similar which are harder to read. SQL queries are good for direct input, mongodb queries styles are better to be used with a programming language;

Your comment made me realize why I prefer to work in ORMs instead of raw SQL, even though I'm frequently frustrated by their limitations - it all comes down to composability. The mongodb syntax looks like it supports composing statements much more readily than SQL. It makes me wonder if there's been any serious work done making a query language that's fully as general as SQL, but is designed to be safely and easily c…

> The mongodb syntax looks like it supports composing statements much more readily than SQL. It makes me wonder if there's been any serious work done making a query language that's fully as general as SQL, but is designed to be safely and easily composable so that you can build queries up from parts.

Haven't you noticed that it's exactly what the Sequel snippet does? It's also what SQLAlchemy's Expression Language does. It's a reification of SQL queries in the host language, so it can/should give pretty much all the tools of SQL.

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