Persisting sorted parquet tables for future sort merge joins

I want to persist a large _sorted_ table to Parquet on S3 and then read this in and join it using the Sorted Merge Join strategy against another large sorted table. The problem is: even though I sort these tables on the join key beforehand, once I persist them to Parquet, they lose the

Persisting sorted parquet tables for future sort merge joins

I want to persist a large _sorted_ table to Parquet on S3 and then read this in and join it using the Sorted Merge Join strategy against another large sorted table. The problem is: even though I sort these tables on the join key beforehand, once I persist them to Parquet, they lose the