Performance Regression in Count Query with Indexed Field #3191

[mamtaRaiTech]

Description

I am experiencing a significant performance regression when counting documents in the reefer_measurements collection using the reefer_id index.

Details

Index Creation:

javascript
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db.reefer_measurements.createIndex({ reefer_id: 1 });

Count Query:

php
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$db = ReeferMeasurementModel::where('reefer_id', '=', $reefer->id);
$total = $db->count();

Performance Comparison:

Version | Execution Time -- | -- 4.8.0 | 3,869.62ms 5.0.0 | 22,550.24ms

Environment

• Laravel-mongodb Version: 5.0.0
• PHP Version: 8.2
• Laravel Version: 11.29.0
• MongoDB Extension Version: 1.20.0
• Collection: reefer_measurements
• Number of Documents: 4 million

Steps to Reproduce

1. Create a collection reefer_measurements with 4 million documents.
2. Create an index on the reefer_id field:

   javascript
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   db.reefer_measurements.createIndex({ reefer_id: 1 });
   

3. Execute the count query as shown above.
4. Compare the performance of the query between versions 4.8.0 and 5.0.0 of the Laravel MongoDB package.

Expected Behavior

The count query should be optimized to leverage the reefer_id index effectively, resulting in consistent or improved performance compared to version 4.8.0.

Actual Behavior

The execution time for the count query has significantly increased in version 5.0.0, leading to degraded application performance.

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Request for Assistance

I would appreciate guidance on:

• Potential causes for this performance regression in version 5.0.0.
• Recommendations for optimizing the count operation to restore or improve performance.

Thank you!

[alcaeus]

This is a carbon copy of #3191, including the issue number in the title. If you have a similar issue, please post updated information in the original issue, but don't copy someone else's problem into a new issue as it only creates noise. Thank you.