That last time I looked, pandas loaded everything. It would be reasonable to implement that iteratively, and fastparquet does have a specific method to do that.
Is there a way to do that query without knowing that row-group 1 is where you want to look
Parquet optionally stores columns max and min values for each row-group, so maybe
split_everyequal or lower than length of
chunksizeignores the uneven chunking of the array)