Copying CompressedPages to new file

[little-arhat]

Hello!

Thansk for this crate!

I'm writing concat tool to merge multiple parquet files into one.
When reading CompressedPages with PageReader, I get back CompessedPages with .selected_rows = None.

When I try to write those pages, write_page expects Some(selected_rows), and my program ultimately fails with "All data pages must declare the number of rows on it" --

parquet2/src/write/row_group.rs

Line 69 in 7a5fc27

Error::oos("All data pages must declare the number of rows on it")

.

Is this hard requirement of parquet format? Can I pass 0 instead, or do I have to decompress/deser & ser/compress pages to copy them to new file?

[little-arhat]

Any tips?