Module export 

Writing the view to an export file.

run takes the view’s plan to a committed file. Uncompressed CSV and Parquet stream: Polars’ sink encodes the plan batch by batch into the OutputFile, and no frame of the whole output is built. Everything else — compressed CSV, JSON, NDJSON, IPC, Avro, any export with the streaming engine off, and builds without it — collects the plan and encodes the frame. Either way the destination changes only at the commit, after the last byte, the encoder’s finish and the final flush have succeeded.

Streaming bounds what the export holds, not what the plan needs: a sort, a group-by or a join still gathers its input before its first row leaves.

Structs

ExportOptions

ExportRequest

One export: the file, its form, and whether it may replace a file there.

Enums

Route

How an export’s rows reach its file.

Functions

encode

Encode df into sink and finish: every buffer is drained, the encoder’s last block and trailer written and sink flushed before this returns, so a failure in any of them is an error here rather than one lost when a writer is dropped.

run

Run an export: plan lf as the format needs (ExportFormat::prepare), write it to the request’s path by its Route, and commit. written hears the bytes written so far: 0 as the write starts, then a few times a second. The destination changes only if every byte was written.