When adding object relationships, we set the nullability of the generated GraphQL field based on whether the database backend enforces that the referenced data always exists. For manual relationships (corresponding to `manual_configuration`), the database backend is unaware of any relationship between data, and hence such fields are always set to be nullable.
For relationships generated from foreign key constraints (corresponding to `foreign_key_constraint_on`), we distinguish between two cases:
1. The "forward" object relationship from a referencing table (i.e. which has the foreign key constraint) to a referenced table. This should be set to be non-nullable when all referencing columns are non-nullable. But in fact, it used to set it to be non-nullable if *any* referencing column is non-nullable, which is only correct in Postgres when `MATCH FULL` is set (a flag we don't consider). This fixes that by changing a boolean conjunction to a disjunction.
2. The "reverse" object relationship from a referenced table to a referencing table which has the foreign key constraint. This should always be set to be nullable. But in fact, it used to always be set to non-nullable, as was reported in hasura/graphql-engine#7201. This fixes that.
Moreover, we have moved the computation of the nullability from `Hasura.RQL.DDL.Relationship` to `Hasura.GraphQL.Schema.Select`: this nullability used to be passed through the `riIsNullable` field of `RelInfo`, but for array relationships this information is not actually used, and moreover the remaining fields of `RelInfo` are already enough to deduce the nullability.
This also adds regression tests for both (1) and (2) above.
https://github.com/hasura/graphql-engine-mono/pull/2159
GitOrigin-RevId: 617f12765614f49746d18d3368f41dfae2f3e6ca
>
### Description
>
This PR supersedes https://github.com/hasura/graphql-engine-mono/pull/1484. Apply `limit` to the table selection before joining relationship rows to improve query performance.
### Changelog
- [x] `CHANGELOG.md` is updated with user-facing content relevant to this PR. If no changelog is required, then add the `no-changelog-required` label.
### Affected components
- [x] Server
### Related Issues
->
Fix https://github.com/hasura/graphql-engine/issues/5745
### Solution and Design
>
Prior to this change, we apply `LIMIT` and `OFFSET` to the outer selection from sub-query which includes joins for relationships. Now, we move `LIMIT` and `OFFSET` (if present) to inner selection of base table. But, this isn't done always! If there are order by relationships' columns we apply at the outer selection. To know more, please refer to [source code note](https://github.com/hasura/graphql-engine-mono/pull/2078/files#diff-46d868ee45d3eaac667cebb34731f573c77d5c9c8097bb9ccf1115fc07f65bfdR652).
```graphql
query {
article(limit: 2){
id
title
content
author{
name
}
}
}
```
Before:
```sql
SELECT
coalesce(json_agg("root"), '[]') AS "root"
FROM
(
SELECT
row_to_json(
(
SELECT
"_4_e"
FROM
(
SELECT
"_0_root.base"."id" AS "id",
"_0_root.base"."title" AS "title",
"_0_root.base"."content" AS "content",
"_3_root.or.author"."author" AS "author"
) AS "_4_e"
)
) AS "root"
FROM
(
SELECT
*
FROM
"public"."article"
WHERE
('true')
) AS "_0_root.base"
LEFT OUTER JOIN LATERAL (
SELECT
row_to_json(
(
SELECT
"_2_e"
FROM
(
SELECT
"_1_root.or.author.base"."name" AS "name"
) AS "_2_e"
)
) AS "author"
FROM
(
SELECT
*
FROM
"public"."author"
WHERE
(("_0_root.base"."author_id") = ("id"))
) AS "_1_root.or.author.base"
) AS "_3_root.or.author" ON ('true')
LIMIT
2
) AS "_5_root"
```
cost
```
Aggregate (cost=0.73..0.74 rows=1 width=32)
-> Limit (cost=0.15..0.71 rows=2 width=32)
-> Nested Loop Left Join (cost=0.15..223.96 rows=810 width=32)
-> Seq Scan on article (cost=0.00..18.10 rows=810 width=72)
-> Index Scan using author_pkey on author (cost=0.15..0.24 rows=1 width=36)
Index Cond: (article.author_id = id)
SubPlan 1
-> Result (cost=0.00..0.01 rows=1 width=32)
SubPlan 2
-> Result (cost=0.00..0.01 rows=1 width=32)
```
After:
```sql
SELECT
coalesce(json_agg("root"), '[]') AS "root"
FROM
(
SELECT
row_to_json(
(
SELECT
"_4_e"
FROM
(
SELECT
"_0_root.base"."id" AS "id",
"_0_root.base"."title" AS "title",
"_0_root.base"."content" AS "content",
"_3_root.or.author"."author" AS "author"
) AS "_4_e"
)
) AS "root"
FROM
(
SELECT
*
FROM
"public"."article"
WHERE
('true')
LIMIT
2
) AS "_0_root.base"
LEFT OUTER JOIN LATERAL (
SELECT
row_to_json(
(
SELECT
"_2_e"
FROM
(
SELECT
"_1_root.or.author.base"."name" AS "name"
) AS "_2_e"
)
) AS "author"
FROM
(
SELECT
*
FROM
"public"."author"
WHERE
(("_0_root.base"."author_id") = ("id"))
) AS "_1_root.or.author.base"
) AS "_3_root.or.author" ON ('true')
) AS "_5_root"
```
cost:
```
Aggregate (cost=16.47..16.48 rows=1 width=32)
-> Nested Loop Left Join (cost=0.15..16.44 rows=2 width=100)
-> Limit (cost=0.00..0.04 rows=2 width=72)
-> Seq Scan on article (cost=0.00..18.10 rows=810 width=72)
-> Index Scan using author_pkey on author (cost=0.15..8.18 rows=1 width=36)
Index Cond: (article.author_id = id)
SubPlan 1
-> Result (cost=0.00..0.01 rows=1 width=32)
SubPlan 2
-> Result (cost=0.00..0.01 rows=1 width=32)
```
https://github.com/hasura/graphql-engine-mono/pull/2078
Co-authored-by: Evie Ciobanu <1017953+eviefp@users.noreply.github.com>
GitOrigin-RevId: 47eaccdbfb3499efd2c9f733f3312ad31c77916f
GJ IR changes cherry-picked from the original GJ branch. There is a separate (can be merged independently) PR for metadata changes (#1727) and there will be a different PR upcoming PR for execution changes.
https://github.com/hasura/graphql-engine-mono/pull/1810
Co-authored-by: Vamshi Surabhi <6562944+0x777@users.noreply.github.com>
GitOrigin-RevId: c31956af29dc9c9b75d002aba7d93c230697c5f4
### Description
In our haste to generalize everything for MSSQL, we put every single "suspicious" type in Backend, including ones that weren't required. `Alias` is one of those: it's only used in a type alias, and is actually just an implementation detail of the translation layer. This PR removes it.
https://github.com/hasura/graphql-engine-mono/pull/1759
GitOrigin-RevId: fb348934ec65a51aae7f95d93c83c3bb704587b5
### Description
This PR removes all `fmapX` and `traverseX` functions from RQL.IR, favouring instead `Functor` and `Traversable` instances throughout the code. This was a relatively straightforward change, except for two small pain points: `AnnSelectG` and `AnnInsert`. Both were parametric over two types `a` and `v`, making it impossible to make them traversable functors... But it turns out that in every single use case, `a ~ f v`. By changing those types to take such an `f :: Type -> Type` as an argument instead of `a :: Type` makes it possible to make them functors.
The only small difference is for `AnnIns`, I had to introduce one `Identity` transformation for one of the `f` parameters. This is relatively straightforward.
### Notes
This PR fixes the most verbose BigQuery hint (`let` instead of `<- pure`).
https://github.com/hasura/graphql-engine-mono/pull/1668
GitOrigin-RevId: e632263a8c559aa04aeae10dcaec915b4a81ad1a
### Description
This PR adds the required IR for DB to DB joins, based on @paf31 and @0x777 's `feature/db-to-db` branch.
To do so, it also refactors the IR to introduce a new type parameter, `r`, which is used to recursively constructs the `v` parameter of remote QueryDBs. When collecting remote joins, we replace `r` with `Const Void`, indicating at the type level that there cannot be any leftover remote join.
Furthermore, this PR refactors IR.Select for readability, moves some code from IR.Root to IR.Select to avoid having to deal with circular dependencies, and makes it compile by adding `error` in all new cases in the execution pipeline.
The diff doesn't make it clear, but most of Select.hs is actually unchanged. Declarations have just been reordered by topic, in the following order:
- type declarations
- instance declarations
- type aliases
- constructor functions
- traverse functions
https://github.com/hasura/graphql-engine-mono/pull/1580
Co-authored-by: Phil Freeman <630306+paf31@users.noreply.github.com>
GitOrigin-RevId: bbdcb4119cec8bb3fc32f1294f91b8dea0728721
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
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
fixes#3868
docker image - `hasura/graphql-engine:inherited-roles-preview-48b73a2de`
Note:
To be able to use the inherited roles feature, the graphql-engine should be started with the env variable `HASURA_GRAPHQL_EXPERIMENTAL_FEATURES` set to `inherited_roles`.
Introduction
------------
This PR implements the idea of multiple roles as presented in this [paper](https://www.microsoft.com/en-us/research/wp-content/uploads/2016/02/FGALanguageICDE07.pdf). The multiple roles feature in this PR can be used via inherited roles. An inherited role is a role which can be created by combining multiple singular roles. For example, if there are two roles `author` and `editor` configured in the graphql-engine, then we can create a inherited role with the name of `combined_author_editor` role which will combine the select permissions of the `author` and `editor` roles and then make GraphQL queries using the `combined_author_editor`.
How are select permissions of different roles are combined?
------------------------------------------------------------
A select permission includes 5 things:
1. Columns accessible to the role
2. Row selection filter
3. Limit
4. Allow aggregation
5. Scalar computed fields accessible to the role
Suppose there are two roles, `role1` gives access to the `address` column with row filter `P1` and `role2` gives access to both the `address` and the `phone` column with row filter `P2` and we create a new role `combined_roles` which combines `role1` and `role2`.
Let's say the following GraphQL query is queried with the `combined_roles` role.
```graphql
query {
employees {
address
phone
}
}
```
This will translate to the following SQL query:
```sql
select
(case when (P1 or P2) then address else null end) as address,
(case when P2 then phone else null end) as phone
from employee
where (P1 or P2)
```
The other parameters of the select permission will be combined in the following manner:
1. Limit - Minimum of the limits will be the limit of the inherited role
2. Allow aggregations - If any of the role allows aggregation, then the inherited role will allow aggregation
3. Scalar computed fields - same as table column fields, as in the above example
APIs for inherited roles:
----------------------
1. `add_inherited_role`
`add_inherited_role` is the [metadata API](https://hasura.io/docs/1.0/graphql/core/api-reference/index.html#schema-metadata-api) to create a new inherited role. It accepts two arguments
`role_name`: the name of the inherited role to be added (String)
`role_set`: list of roles that need to be combined (Array of Strings)
Example:
```json
{
"type": "add_inherited_role",
"args": {
"role_name":"combined_user",
"role_set":[
"user",
"user1"
]
}
}
```
After adding the inherited role, the inherited role can be used like single roles like earlier
Note:
An inherited role can only be created with non-inherited/singular roles.
2. `drop_inherited_role`
The `drop_inherited_role` API accepts the name of the inherited role and drops it from the metadata. It accepts a single argument:
`role_name`: name of the inherited role to be dropped
Example:
```json
{
"type": "drop_inherited_role",
"args": {
"role_name":"combined_user"
}
}
```
Metadata
---------
The derived roles metadata will be included under the `experimental_features` key while exporting the metadata.
```json
{
"experimental_features": {
"derived_roles": [
{
"role_name": "manager_is_employee_too",
"role_set": [
"employee",
"manager"
]
}
]
}
}
```
Scope
------
Only postgres queries and subscriptions are supported in this PR.
Important points:
-----------------
1. All columns exposed to an inherited role will be marked as `nullable`, this is done so that cell value nullification can be done.
TODOs
-------
- [ ] Tests
- [ ] Test a GraphQL query running with a inherited role without enabling inherited roles in experimental features
- [] Tests for aggregate queries, limit, computed fields, functions, subscriptions (?)
- [ ] Introspection test with a inherited role (nullability changes in a inherited role)
- [ ] Docs
- [ ] Changelog
Co-authored-by: Vamshi Surabhi <6562944+0x777@users.noreply.github.com>
GitOrigin-RevId: 3b8ee1e11f5ceca80fe294f8c074d42fbccfec63
Fixes https://github.com/hasura/graphql-engine/issues/5704 by checking, for aggregate fields whether we are handling a numeric aggregation.
This PR also adds type information to `ColFld` such that we know the type of the field.
This is the second attempt. See #319 for a less invasive approach. @nicuveo suggested type information might be useful, and since it wasn't hard to add, I think this version is better as well.
GitOrigin-RevId: aa6a259fd5debe9466df6302839ddbbd0ea659b5
This PR is a combination of the following other PRs:
- #169: move HasHttpManager out of RQL.Types
- #170: move UserInfoM to Hasura.Session
- #179: delete dead code from RQL.Types
- #180: move event related code to EventTrigger
GitOrigin-RevId: d97608d7945f2c7a0a37e307369983653eb62eb1
This is an incremental PR towards https://github.com/hasura/graphql-engine/pull/5797
Co-authored-by: Anon Ray <ecthiender@users.noreply.github.com>
GitOrigin-RevId: a6cb8c239b2ff840a0095e78845f682af0e588a9
Generalize TableCoreInfoRM, TableCoreCacheRT, some table metadata data types, generalize fromPGCol to fromCol, generalize some schema cache functions, prepare some enum schema cache code for generalization
GitOrigin-RevId: a65112bc1688e00fd707d27af087cb2585961da2
This PR makes a bunch of schema generation code in Hasura.GraphQL.Schema backend-agnostic, by moving the backend-specific parts into a new BackendSchema type class. This way, the schema generation code can be reused for other backends, simply by implementing new instances of the BackendSchema type class.
This work is now in a state where the schema generators are sufficiently generic to accept the implementation of a new backend. That means that we can start exposing MS SQL schema. Execution is not implemented yet, of course.
The branch currently does not support computed fields or Relay. This is, in a sense, intentional: computed field support is normally baked into the schema generation (through the fieldSelection schema generator), and so this branch shows a programming technique that allows us to expose certain GraphQL schema depending on backend support. We can write support for computed fields and Relay at a later stage.
Co-authored-by: Antoine Leblanc <antoine@hasura.io>
GitOrigin-RevId: df369fc3d189cbda1b931d31678e9450a6601314
