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"No reason to use MongoDB in 2017" I would reply: replica sets and sharding and multi-threaded architecture and the absence of impedance mismatch, all in a sin

"No reason to use MongoDB in 2017" I would reply: replica sets and sharding and multi-threaded architecture and the absence of impedance mismatch, all in a single product that was designed for these features.

user5994461 9y ago
Have you actually used replica set and sharding? I did and it is a complete disaster in MongoDB.
- threeseed 9y ago
  Yes. With hundreds of nodes. MongoDB also has some very large customers using it so clearly it isn't a complete disaster. I would chose to use it over PostgreSQL any day of the week (not that there is a clear option regardless).
camus2 9y ago
> I would reply: replica sets and sharding and multi-threaded architecture and the absence of impedance mismatch, all in a single product that was designed for these features. If you don't care about data integrity, transactions and efficiency, then by all means. But in that case, a distributed file system is as efficient. > multi-threaded architecture I fail to see how a multi-threaded architecture is a problem with Postgres. > the absence of impedance mismatch Postgres supports JSON type(and XML), so no.
- anarazel 9y ago
  > > multi-threaded architecture > I fail to see how a multi-threaded architecture is a problem with Postgres. While it's not a fundamental issue, it does have some considerable drawbacks. A lot of the work required to make query processing use multiple cores (9.6, and the upcoming 10 release), would've been a lot easier if there were a shared memory space. There's no portable way to guarantee that shared memory that's allocated after process start can be mapped to the same addresses in different processes, so you've to deal with a relative addressing etc, which both complicates and slows down. There's also upsides, don't get me wrong. Primarily around robustness in case of failures, but also some around resource isolation.
tscs37 9y ago
CockroachDB called, problem solved for SQL with ACID. Replication and Sharding are easy.
- threeseed 9y ago
  How is this relevant ? MongoDB is a document database. If you use CockroachDB you lose this capability.
- jackweirdy 9y ago
  CockroachDB reached 1.0 less than 2 months ago. I'm not sure what your domain is, but personally I would be very hesitant to go with a database which is so new
  - elmigranto 9y ago
    MongoDB escaped being glorified /dev/null just last fall. https://jepsen.io/analyses/mongodb-3-4-0-rc3 https://jepsen.io/analyses/mongodb-3-4-0-rc3
    - jackweirdy 9y ago
      Exactly, this is an argument in waiting for the real-world behaviour of the database to be well understood

user5994461 9y ago

Have you actually used replica set and sharding? I did and it is a complete disaster in MongoDB.

threeseed 9y ago
Yes. With hundreds of nodes. MongoDB also has some very large customers using it so clearly it isn't a complete disaster. I would chose to use it over PostgreSQL any day of the week (not that there is a clear option regardless).

camus2 9y ago

> I would reply: replica sets and sharding and multi-threaded architecture and the absence of impedance mismatch, all in a single product that was designed for these features. If you don't care about data integrity, transactions and efficiency, then by all means. But in that case, a distributed file system is as efficient. > multi-threaded architecture I fail to see how a multi-threaded architecture is a problem with Postgres. > the absence of impedance mismatch Postgres supports JSON type(and XML), so no.

anarazel 9y ago
> > multi-threaded architecture > I fail to see how a multi-threaded architecture is a problem with Postgres. While it's not a fundamental issue, it does have some considerable drawbacks. A lot of the work required to make query processing use multiple cores (9.6, and the upcoming 10 release), would've been a lot easier if there were a shared memory space. There's no portable way to guarantee that shared memory that's allocated after process start can be mapped to the same addresses in different processes, so you've to deal with a relative addressing etc, which both complicates and slows down. There's also upsides, don't get me wrong. Primarily around robustness in case of failures, but also some around resource isolation.

tscs37 9y ago

CockroachDB called, problem solved for SQL with ACID. Replication and Sharding are easy.

threeseed 9y ago
How is this relevant ? MongoDB is a document database. If you use CockroachDB you lose this capability.
jackweirdy 9y ago
CockroachDB reached 1.0 less than 2 months ago. I'm not sure what your domain is, but personally I would be very hesitant to go with a database which is so new
- elmigranto 9y ago
  MongoDB escaped being glorified /dev/null just last fall. https://jepsen.io/analyses/mongodb-3-4-0-rc3 https://jepsen.io/analyses/mongodb-3-4-0-rc3
  - jackweirdy 9y ago
    Exactly, this is an argument in waiting for the real-world behaviour of the database to be well understood