Module arrow_conversion 

Available on (crate features default-engine-native-tls or default-engine-rustls or arrow-conversion) and crate feature arrow-conversion only.

Conversions between kernel schema types and arrow schema types.

Two directions, used at the engine <-> kernel boundary:

• arrow -> kernel (TryFromArrow / TryIntoKernel): an example usage is converting a checkpoint Parquet file’s Arrow footer schema into a kernel StructType during log replay.

• kernel -> arrow (TryFromKernel / TryIntoArrow): an example usage is materializing a kernel StructType as an ArrowSchema to build a RecordBatch on the write path.

These conversions can be used on both logical and physical schemas. E.g. when writing a parquet file, the default engine converts the physical kernel schema to an Arrow schema and writes the data. When transforming physical data to logical data via an Expression, DefaultExpressionEvaluator converts the logical schema to an Arrow schema as the output schema.

Modules

scalar

Extract a kernel Scalar from a single row of an Arrow array.

Traits

TryFromArrow

Convert an arrow type into a kernel type (a similar TryIntoKernel trait is automatically implemented for all types that implement TryFromArrow)

TryFromKernel

Convert a kernel type into an arrow type (a similar TryIntoArrow trait is automatically implemented for all types that implement TryFromKernel)

TryIntoArrow

Convert a kernel type into an arrow type (automatically implemented for all types that implement TryFromKernel)

TryIntoKernel

Convert an arrow type into a kernel type (automatically implemented for all types that implement TryFromArrow)