Eloquent Query Tuning Headache

Hi everyone, I'm currently knee-deep in developing a new reporting module for our 'Laravel Quick Fix & Consultation' service, which involves aggregating quite a bit of complex user data. We're running into some significant performance issues with a particular Eloquent query, and I'm looking for some advanced strategies for Laravel performance optimization.

The module's main goal is to fetch comprehensive data across several related models: users, their subscriptions, activities, and custom events. While the Eloquent query I've constructed is logically sound and retrieves the correct data, it's causing unacceptable load times, especially as our dataset grows. We're consistently observing query execution times exceeding 10-15 seconds for just a few thousand records, which is obviously not scalable.

Here’s what I’ve attempted so far to diagnose and mitigate the problem:

• Used DB::listen and Laravel Debugbar extensively to profile queries, which confirmed a specific aggregate query as the primary bottleneck.
• Implemented eager loading (with()) for all relevant relationships to minimize N+1 issues.
• Added appropriate database indexes to all foreign keys and frequently queried columns, based on analysis from EXPLAIN output.
• Tried breaking down the monolithic query into smaller, more manageable chunks, but the re-aggregation logic became overly complex and didn't yield significant performance gains.
• Explored direct raw SQL alternatives, but my preference is to stick with Eloquent for better maintainability and readability if at all possible.

Despite these efforts, I'm still hitting a wall. Here’s a simplified representation of the problematic Eloquent query’s structure and a snippet of the EXPLAIN output that indicates the core issue – a full table scan despite existing indexes:

// Simplified problematic Eloquent query structure
$reports = User::query()
    ->with(['subscriptions', 'activities', 'events'])
    ->whereHas('subscriptions', function ($query) {
        $query->where('status', 'active');
    })
    ->whereHas('activities', function ($query) {
        $query->where('type', 'login')->where('created_at', '>', now()->subMonths(3));
    })
    ->selectRaw('users.*, (SELECT COUNT(*) FROM subscriptions WHERE user_id = users.id AND status = "active") as active_subscriptions_count')
    ->orderBy('active_subscriptions_count', 'desc')
    ->paginate(50);

// EXPLAIN output snippet showing the bottleneck
+----+-------------+------------+------------+-------+-------------------------------------------------+---------------------+---------+-------------------+------+----------+--------------------------------------------------------+
| id | select_type | table      | partitions | type  | possible_keys                                   | key                 | key_len | ref               | rows | filtered | Extra                                                  |
+----+-------------+------------+------------+-------+-------------------------------------------------+---------------------+---------+-------------------+------+----------+--------------------------------------------------------+
|  1 | PRIMARY     | users      | NULL       | ALL   | NULL                                            | NULL                | NULL    | NULL              | 150K |   100.00 | Using temporary; Using filesort                        |
|  2 | SUBQUERY    | subscriptions | NULL    | ref   | subscriptions_user_id_foreign                   | subscriptions_user_id_foreign | 8       | example_db.users.id |    1 |    10.00 | Using where; Using index                               |
|  3 | DEPENDENT SUBQUERY | subscriptions | NULL | ref | subscriptions_user_id_foreign                   | subscriptions_user_id_foreign | 8       | example_db.users.id |    1 |    10.00 | Using where; Using index                               |
|  4 | DEPENDENT SUBQUERY | activities | NULL | ref | activities_user_id_foreign                      | activities_user_id_foreign | 8       | example_db.users.id |    1 |    10.00 | Using where; Using index                               |
+----+-------------+------------+------------+-------+-------------------------------------------------+---------------------+---------+-------------------+------+----------+--------------------------------------------------------+

The critical observation here is the PRIMARY select_type on the users table showing type: ALL and Using temporary; Using filesort. This strongly indicates a full table scan and inefficient sorting, which is confounding given that user_id indexes exist on all related tables. It seems the aggregate subquery within selectRaw combined with the orderBy on its alias is preventing effective index usage for the main `users` table.

My core question is: what advanced Eloquent or database-level strategies can be employed here for significant Eloquent query tuning? Are there specific Laravel techniques for handling complex aggregations and sorting on computed columns that avoid these performance pitfalls, or should I be seriously considering a different architectural approach like materialised views, a dedicated reporting database, or even pushing these aggregations into a NoSQL store for reporting? Any insights on how to optimize this particular pattern within a Laravel context would be immensely helpful.

Thanks in advance for any insights!