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“MongoDB is dead. Long live Postgresql”

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Re: “MongoDB is dead. Long live Postgresql”

#81

Post by dev360 »

ehwizard wrote: post #27
dev360 wrote: post #24

Earlier quoted context omitted.

In all fairness, the compaction is a major pain in Mongo. I get a little worked up about this because I cant think of another database that handles compaction this poorly, but feel free to correct me if Im wrong.

Have you tried turning on power of 2 allocation? In general, it makes compaction much less important. Though online compaction is definitely needed.

Yes we switched to it a month ago, which improved it but like you said, we are still having to compact frequently and having the hassle of switching the primary. Cassandra has turned out to be much more performant and easier to maintain for our use case.

Re: “MongoDB is dead. Long live Postgresql”

#82

Post by endijs »

sigzero wrote: post #71
endijs wrote: post #65

I'm no MongoDB expert, but recently started to look into this db. Can anyone tell me (from experience, not from promo materials) - for which use cases MongoDB is good fit and for which ones it's not? It's clear that it can't fit for everyone. That's why it would be good to know in advance, for what it most likely to find and for what it's most likely not to fit.

http://kkovacs.eu/cassandra-vs-mongodb-vs-couchdb-vs-redis

This is more like how it is in theory. I was hoping for more real life stories. "We had problem X, tried MongoDB, but failed because of ...", "We had problem Z, MongoDB works better than R, because..."

Re: “MongoDB is dead. Long live Postgresql”

#84

Post by andrewvc »

jcampbell1 wrote: post #18
seiji wrote: post #3

Earlier quoted context omitted.

PostgreSQL has native json support now. What else is missing? Just a protocol implementation? I'd love to see MongoDB give up and become a PostgreSQL consultancy. Everybody I talk to in the field has the exact same Mongo story: "We love JSON! We use JSON everywhere! We just wanted a DB with native JSON support. We didn't look at the implementation details. We only looked at their marketing. Now we wake up at 3am to f…

It is probably not as simple as "supports json now". Imagine if HN comments were stored as a JSON document: Client A: Read JSON. Client B: Read JSON. Client A: Append new comment to json document. Client B: Append new comment to json document. Client A: Save JSON Client B: Save JSON A's comment will get deleted. My understanding is that Mongo DB does have a way to append a record within a document, but Postgres does…

Postgres CAN do exactly this, in fact, this is the sort of thing it excels at, the transactions in postgres can do this, and so much more.

I think what you're talking about is appending with a single statement, which Postgres can also do. You can deserialize JSON inside a postgres query, alter parts of it, serialize it again, then store it in a single atomic transaction using an UPDATE.

Re: “MongoDB is dead. Long live Postgresql”

#85

Post by mikegioia »

endijs wrote: post #65

I'm no MongoDB expert, but recently started to look into this db. Can anyone tell me (from experience, not from promo materials) - for which use cases MongoDB is good fit and for which ones it's not? It's clear that it can't fit for everyone. That's why it would be good to know in advance, for what it most likely to find and for what it's most likely not to fit.

It has the benefits and ease of use of a json document store, it allows you to do SQL style where clauses, it takes about a minute to install and start using, there are a wide range of drivers available for many languages, and it has a simple javascript map/reduce.

on the flip side, it implements database level locking, uses more disk/RAM than it probably should, and can start to give you headaches if you try to do a lot of writes at once.

edit: to give you a real world example, we use mariadb for storing everything persistently. however, a lot of data like "number of teachers in school A" is aggregated and too difficult to run in real time when we render paged results. to get around that, we use mongo as a document store and use its SQL like querying to generate the paged search results. this lets us sort/filter on the data without having to do everything in SQL.

Re: “MongoDB is dead. Long live Postgresql”

#86

Post by threeseed »

derefr wrote: post #54
rlpb wrote: post #30

Earlier quoted context omitted.

> Seriously, another case of using Mongo incorrectly? If a large proportion of MongoDB users are using it incorrectly, then I'd argue that it is a MongoDB problem, if only a documentation and messaging one. Clarity on what is and is not an appropriate use should be prominent. So, what is this proportion?

Or, to be even more specific--if there's a Right Way to use a program, that Right Way should be encoded as defaults you have to override (if you know what you're doing), and automated actions you have to disable (if you know what you're doing.)

It has nothing to do with the defaults. It is all about people forgetting that MongoDB is a document database and not a relational one. I can write apps that will be 10x faster with MongoDB and 10x faster with PostgreSQL. It's all about matching your domain model to your database.

Re: “MongoDB is dead. Long live Postgresql”

#87

Post by felideon »

spellboots wrote: post #61
pilif wrote: post #46

The title is a bit misleading. This is basically an announcement of a fork of Errbit that has Postgres support. Additionally, the fork was announced as an issue on errbit with no discussion or as an official pull request. I would not consider this good etiquette. If you fork your project (especially without discussing the intention first), adding a bug to the original project isn't a very nice thing to do. An officia…

I disagree, I think that opening an issue on github is a good way to start a discussion about a feature. Many projects accept feature requests this way and if anyone did the same for one of my projects, this would be the way I would prefer them to handle it.

The thing is it sounds like he is just promoting his own fork he started 11 months ago, rather than "starting a discussion."

> We suggest to put errbit on PG. For those who want to try - the code here: https://github.com/Undev/errbit/tree/pg-upstream

The problem here is that the bad English grammar could have given the wrong impression. Maybe he is just saying:

"hey guys, you should consider migrating to postgresql. here's some code you can check out that has worked for us."

Rather than:

"hey guys, screw Errbit/MongoDB, use our fork!"

Re: “MongoDB is dead. Long live Postgresql”

#89

Post by threeseed »

mml wrote: post #9

The hstore enhancements coming in psql 9.4 will pretty much put mongo out to pasture. "Mongodb" already nearly exists as a single column type, 9.4 will complete it.

Right. Just like MySQL/Oracle was put out to pasture.

And if you think MongoDB is only popular because it is a JSON store then it shows just little you know about the database landscape and about how developers actually use databases.

Re: “MongoDB is dead. Long live Postgresql”

#90

Post by hrjet »

jcampbell1 wrote: post #18
seiji wrote: post #3

Earlier quoted context omitted.

PostgreSQL has native json support now. What else is missing? Just a protocol implementation? I'd love to see MongoDB give up and become a PostgreSQL consultancy. Everybody I talk to in the field has the exact same Mongo story: "We love JSON! We use JSON everywhere! We just wanted a DB with native JSON support. We didn't look at the implementation details. We only looked at their marketing. Now we wake up at 3am to f…

It is probably not as simple as "supports json now". Imagine if HN comments were stored as a JSON document: Client A: Read JSON. Client B: Read JSON. Client A: Append new comment to json document. Client B: Append new comment to json document. Client A: Save JSON Client B: Save JSON A's comment will get deleted. My understanding is that Mongo DB does have a way to append a record within a document, but Postgres does…

But then that could be handled by the compatibility layer.
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