Expose PostgreSQL JSON operators

[roji]

From @roji on September 8, 2015 7:56

PostgreSQL supports a wide array of JSON operations. We may be able to translate at least some JSON operations in LINQ queries to PostgreSQL for backend processing - this would prevent the entire resultset from being pulled in to the client.

Explore the Newtonsoft.JSON API to see what can be done. We also probably don't want to take a dependency on Newtonsoft.JSON from the EF7 provider, so reference the JSON methods via reflection.

It may be a good idea to provide an opt-out for this in case there's trouble or client-side evaluation is preferred. At the query and model levels.

Copied from original issue: npgsql/npgsql#771

[ma3yta]

Hello @roji,

how progress on this task?

[roji]

Unfortunately not, I've been busy with more important/basic things...

I'm also not 100% sure it's a good idea to attack this before the general EFCore JSON story becomes clearer: dotnet/efcore#4021 (comment). We would risk going down our own specific path etc.

[roji]

It may be a good idea to look at standardized SQL/JSON support: https://wiki.postgresql.org/wiki/Postgres_Professional_roadmap#SQL.2FJSON_standard. This may even be a cross-database thing.

[roji]

Superceded by #334