Remote relationships are now supported on SQL Server and BigQuery. The major change though is the re-architecture of remote join execution logic. Prior to this PR, each backend is responsible for processing the remote relationships that are part of their AST.
This is not ideal as there is nothing specific about a remote join's execution that ties it to a backend. The only backend specific part is whether or not the specification of the remote relationship is valid (i.e, we'll need to validate whether the scalars are compatible).
The approach now changes to this:
1. Before delegating the AST to the backend, we traverse the AST, collect all the remote joins while modifying the AST to add necessary join fields where needed.
1. Once the remote joins are collected from the AST, the database call is made to fetch the response. The necessary data for the remote join(s) is collected from the database's response and one or more remote schema calls are constructed as necessary.
1. The remote schema calls are then executed and the data from the database and from the remote schemas is joined to produce the final response.
### Known issues
1. Ideally the traversal of the IR to collect remote joins should return an AST which does not include remote join fields. This operation can be type safe but isn't taken up as part of the PR.
1. There is a lot of code duplication between `Transport/HTTP.hs` and `Transport/Websocket.hs` which needs to be fixed ASAP. This too hasn't been taken up by this PR.
1. The type which represents the execution plan is only modified to handle our current remote joins and as such it will have to be changed to accommodate general remote joins.
1. Use of lenses would have reduced the boilerplate code to collect remote joins from the base AST.
1. The current remote join logic assumes that the join columns of a remote relationship appear with their names in the database response. This however is incorrect as they could be aliased. This can be taken up by anyone, I've left a comment in the code.
### Notes to the reviewers
I think it is best reviewed commit by commit.
1. The first one is very straight forward.
1. The second one refactors the remote join execution logic but other than moving things around, it doesn't change the user facing functionality. This moves Postgres specific parts to `Backends/Postgres` module from `Execute`. Some IR related code to `Hasura.RQL.IR` module. Simplifies various type class function signatures as a backend doesn't have to handle remote joins anymore
1. The third one fixes partial case matches that for some weird reason weren't shown as warnings before this refactor
1. The fourth one generalizes the validation logic of remote relationships and implements `scalarTypeGraphQLName` function on SQL Server and BigQuery which is used by the validation logic. This enables remote relationships on BigQuery and SQL Server.
https://github.com/hasura/graphql-engine-mono/pull/1497
GitOrigin-RevId: 77dd8eed326602b16e9a8496f52f46d22b795598
This reverts the remote schema type customisation and namespacing feature temporarily as we test for certain conditions.
GitOrigin-RevId: f8ee97233da4597f703970c3998664c03582d8e7
This is a minor refactor (part of `Internal/Parser.hs` is moved into `Internal/Input.hs`) to remove `Collect.hs-boot` and `Directives.hs-boot` files. Without these changes:
1. Most changes would trigger recompilation from the modules with hs-boot files.
1. haskell-language-server fails for some reason in the presence of hs-boot files.
GitOrigin-RevId: 77a2e443417b449c5d7d9d418fc75fcdf076a9ae
Multi source support had limited the availability of async action queries in subscriptions. This PR
adds support for async action query subscriptions with new implementation. Also addresses https://github.com/hasura/graphql-engine/issues/6460.
GitOrigin-RevId: 5ddc321073d224f287dc4b86ce2239ff55190b36
While debugging issues with HLS, Reed Mullanix noticed that we don't use relative paths. This leads to problems when using HLS + Emacs due to a bug in `lsp-mode` which prevents it from finding the correct project root.
However, it is still a good practice to use relative paths in TH for other reasons, including being able to import these modules in GHCI.
This PR should make it so HLS-1.0 & emacs provide type inference, imports, etc., in all modules in our codebase.
GitOrigin-RevId: 5f53b9a7ccf46df1ea7be94ff0a5c6ec861f4ead
Fixes https://github.com/hasura/graphql-engine-mono/issues/712
Main point of interest: the `Hasura.SQL.Backend` module.
This PR creates an `Exists` type indexed by indexed type and packed constraint while hiding all of its complexity by not exporting the constructor.
Existential constructors/types which are no longer (directly) existential:
- [X] BackendSourceInfo :: BackendSourceInfo
- [x] BackendSourceMetadata :: BackendSourceMetadata
- [x] MOSourceObjId :: MetadatObjId
- [x] SOSourceObj :: SchemaObjId
- [x] RFDB :: RootField
- [x] LQP :: LiveQueryPlan
- [x] ExecutionStep :: ExecStepDB
This PR also removes ALL usages of `Typeable.cast` from our codebase. We still need to derive `Typeable` in a few places in order to be able to derive `Data` in one place. I have not dug deeper to see why this is needed.
GitOrigin-RevId: bb47e957192e4bb0af4c4116aee7bb92f7983445
