Slow index request because fields are loaded despite defined fieldsForIndex

[m-lotze]

• Laravel Version: 9.19.0
• Nova Version: 4.11.0

Description:

When a resource defines fieldsForIndex the fields method is still executed for each resource on an index request. When you have a lot of fields and e.g. load relations and so on, this slows down the index request a lot. In our case changing the fields method like this improves the loading speed quite a bit:

public function fields(NovaRequest $request): array
{
    if ($request->isResourceIndexRequest()) {
        return [];
    }

   ...
}

I assume this is also the case for other methods like fieldsForDetail. I think Nova should only load fields if there are no other methods defined for the specific request.

[crynobone]

We uses fields to verify multiple logic but that's shouldn't have much affect. My guess you have some heavy processing code running under fields() which causes the performance issues.

[juse-less]

Depending on where you load the relationships, I recommend implementing Resource::indexQuery(), and/or Resource::detailQuery().

I couldn't find this directly referenced in the documentation right now, but you can see some examples for both pre-defined query methods, as well as dynamic ones at documentaion/resources/authorization.
Like indexQuery, and relatableQuery (which can be dynamically implemented).

Also keep in mind - if you'll always load relationships, regardless of page 'type', you can define the $with property, just like in Models.

// Keep in mind - only BelongsTo (and equivalent) relationships are presented on indexes.
// If you need to present a summary of a HasMany relationship, or so, you can load that as well.
public static function indexQuery(NovaRequest $request, $query)
{
    return parent::indexQuery($request, $query->with([
        'user',
        'someBelongsTo',
        'otherRelation',
        // ...
    ]));
}

// All relationships can be presented.
public static function detailQuery(NovaRequest $request, $query)
{
    return parent::detailQuery($request, $query->with([
        'user',
        'someHasMany',
        'otherRelation',
        // ...
    ]));
}