[makkesk8]

One big drawback of postgres when updating data in a jsonb column is that it needs to rewrite everything even when you update the value of a single key, this gets very expensive if you need to update many rows. As far as I can tell, Mongodb handles this better. Other than this I also prefer postgres despite this limitation.

[jabberwcky]

Mongo stores objects pretty much the same as PG here, a single key update requires a rewrite of the object. Maybe Mongo has some fancy algorithms to avoid full decode/reencode in some cases, but in principle the physical data formats are almost identical

[isbvhodnvemrwvn]

In a tiny bit more detail - mongo uses BSON, which is effectively TLV encoded json. I'm not sure how storage of entire collections is done though.

https://en.wikipedia.org/wiki/BSON

[rualca]

> (...) BSON, which is effectively TLV encoded json.

For those who, like me, never heard of TLV prior to this post, it's type-length-value encoding.

https://en.wikipedia.org/wiki/Type-length-value

[swyx]

thanks for the link, you weren't alone

[karsinkk]

Disclaimer : I'm a Software Engineer at Oracle

In Oracle 21c and the Autonomous JSON Database, we introduced a new Native JSON Datatype with it's own Binary Storage format called OSON[1]. With OSON, you can perform partial updates on a json document. The added benefit is that this results in significantly lesser redo log size.

[1] https://blogs.oracle.com/jsondb/osonformat

[dan-robertson]

Are there any (independent) benchmarks for how the performance of this compares to other database management systems?

[twic]

The benchmark should really compare Oracle to PostgreSQL with however much extra RAM the cost of an Oracle license would buy.

[j16sdiz]

I think standard Oracle license prohibite benchmarking.

[samb1729]

This sounds like a fantastic reason among many to actively resist ever using their software.