Bye Bye Mongo, Hello Postgres

Re:Bye Bye Mongo, Hello Postgres by quietbritishjim on Wednesday December 19, 2018 @08:08PM (#18721651)

As I said to a sibling response, this is not a substitute for Mongo's aggregation pipeline unless it can do analogous things to Postgres's JSONB fields. For example, can it unwind an array field, match those subrecords where one field (like a "key") matches a value and another field (like a "value") exceeds an overall value, and then apply this condition to filter the overall rows in the table?

Also, one of the benefits of Mongo's API is that it has excellent native implementations in numerous languages (we already use C++ and Python), so a suggestion to switch language entirely is not really equivalent.

[ Parent | on HN ]

Re:Bye Bye Mongo, Hello Postgres by inferiorhuman on Wednesday December 19, 2018 @09:01PM (#18721925)

> As I said to a sibling response, this is not a substitute for Mongo's aggregation pipeline

Huh? The aggregation framework is a solution to a mongo-only problem. Most other databases are performant, but Mongo suffers wildly from coarse locking and slow performance putting things into and retrieving things from the javascript VM.

> For example, can it unwind an array field, match those subrecords where one field (like a "key") matches a value and another field (like a "value") exceeds an overall value, and then apply this condition to filter the overall rows in the table?

This sounds suspiciously like a SQL view.

Edit: But if you actually need an array in a cell, Postgres has an array type that's also a first-class citizen with plenty of tooling around it.

[ Parent | on HN ]

Re:Bye Bye Mongo, Hello Postgres by quietbritishjim on Wednesday December 19, 2018 @09:39PM (#18722065)

The "this" was referring to dynamically building queries (the GP comment by me) in Ecto (the parent comment by QuinnWilton). What you've said is a non-sequitur in the context of this little discussion. My whole original point is that raw SQL isn't right in all situations, and you appear to be arguing that I just use SQL instead.

[ Parent | on HN ]

Re:Bye Bye Mongo, Hello Postgres by inferiorhuman on Wednesday December 19, 2018 @09:50PM (#18722118)

I can't speak to every ORM or database interface in existence but ActiveRecord will happily handle Postgres arrays and let you use the built-in array functions just handily without having to write queries by hand. Ecto is less elegant, but you can still finangle some arrays with it.

As far as views are concerned, I don't know what to tell you. Sure, you'll probably have to craft the view itself by hand. The result is that you can then use most abstractions of your choosing on top of it though.

[ Parent | on HN ]

Re:Bye Bye Mongo, Hello Postgres by bonesss on Thursday December 20, 2018 @07:08AM (#18724202)

There's also the possibility of using automation to create, update, and manage views. That lets your app be 'dynamic' with regards to new data and new datatypes, but also preserves the performance, debugging, segregation, and maintenance benefits of the underlying DB.

[ Parent | on HN ]

Re:Bye Bye Mongo, Hello Postgres by xkcd-sucks on Wednesday December 19, 2018 @09:24PM (#18722010)

>For example, can it...

Yes. There will be a subquery and jsonb indexes need to be thought out in order to make it fast

[ Parent | on HN ]