Module export 

Embeddable export writers (Epic #682)

This module hosts writers that convert query results into external file formats so that non-CLI consumers (projection services, the Python/Node bindings, library embedders) can produce them without shelling out to the CLI.

Feature flags

Submodule	Feature	In defaults?
arrow_convert	arrow	No
parquet	parquet	No
delta_schema	delta-scan + arrow	No
delta_parquet	delta-scan + parquet	No

The arrow feature pulls in the arrow crate as an optional dependency and exposes build_arrow_schema / rows_to_record_batch for use by any consumer that wants Arrow RecordBatches without Parquet.

The parquet feature depends on arrow and additionally pulls in the parquet crate; it is off by default so the default build’s dependency surface is unchanged.

The delta_parquet module (DS8, Issue #704) is compiled only when both delta-scan and parquet are enabled. It depends on delta_schema (DS7, Issue #703) for schema derivation and reuses the epic #682 Arrow writer machinery — no forked writer.

External-committer boundary

Per the decisions in docs/architecture/cassandra-sidecar-parquet-projections.md, CQLite produces Parquet files only. Committing those files to lakehouse table formats (Iceberg, Delta) — manifest/metadata transactions, snapshot management — is the job of an external committer and is deliberately out of scope for this crate.

Re-exports

pub use arrow_convert::build_arrow_schema;

pub use arrow_convert::rows_to_record_batch;

pub use arrow_convert::ArrowConvertError;

pub use delta_schema::derive_delta_schema;

pub use delta_schema::DeltaSchemaError;

pub use delta_schema::DeltaSchemaOpts;

pub use delta_parquet::write_delta_records_to_bytes;

pub use delta_parquet::DeltaParquetCompression;

pub use delta_parquet::DeltaParquetError;

pub use delta_parquet::DeltaParquetOptions;

pub use delta_parquet::DeltaParquetWriter;

Modules

arrow_convert

CQL → Arrow RecordBatch conversion (feature = “arrow”)

delta_parquet

Delta-scan Parquet writer (Epic #696, Issue #704).

delta_schema

Delta-scan Arrow schema derivation (Epic #696, Issue #703).

parquet

Parquet export writer for QueryResult (feature = “parquet”)