First 5Gb are not 5Gb 🤔 
Some datasets*, for example [vivym/midjourney-messages](https://huggingface.co/datasets/vivym/midjourney-messages) and [Open-Orca/OpenOrca](https://huggingface.co/datasets/Open-Orca/OpenOrca) are not fully converted or copied(?) to parquet export. 
These two are originally both in parquet format
* midjourney original parquet files are about 8-9Gb in total, so the part of the data for datasets-server should be about 5Gb for sure but the viewer shows 1.56Gb:
![image](https://github.com/huggingface/datasets-server/assets/16348744/b899d1ba-7264-494e-8f62-8dc26716d003)

* original OpenOrca is two parquet files about 4Gb in size total but the viewer shows 2.85Gb:
![image](https://github.com/huggingface/datasets-server/assets/16348744/9b5194b2-7e5c-4d1f-8ba6-25a29891b575)

Am I misunderstanding something or is it a bug?

*idk i assume there might be more of them but i have these two examples in mind.
First 5Gb are not 5Gb 🤔 : Some datasets*, for example [vivym/midjourney-messages](https://huggingface.co/datasets/vivym/midjourney-messages) and [Open-Orca/OpenOrca](https://huggingface.co/datasets/Open-Orca/OpenOrca) are not fully converted or copied(?) to parquet export. 
These two are originally both in parquet format
* midjourney original parquet files are about 8-9Gb in total, so the part of the data for datasets-server should be about 5Gb for sure but the viewer shows 1.56Gb:
![image](https://github.com/huggingface/datasets-server/assets/16348744/b899d1ba-7264-494e-8f62-8dc26716d003)

* original OpenOrca is two parquet files about 4Gb in size total but the viewer shows 2.85Gb:
![image](https://github.com/huggingface/datasets-server/assets/16348744/9b5194b2-7e5c-4d1f-8ba6-25a29891b575)

Am I misunderstanding something or is it a bug?

*idk i assume there might be more of them but i have these two examples in mind.