Module batch_reader 

Arrow RecordBatch → EventRow bridge for Ring 0 input.

BatchRowReader decomposes columnar Arrow data into row-oriented EventRows allocated in a bump arena. This is the reverse of RowBatchBridge, which converts rows back to Arrow RecordBatch.

Usage

use std::sync::Arc;
use arrow_array::{Int64Array, Float64Array, RecordBatch};
use arrow_schema::{DataType, Field, Schema};
use bumpalo::Bump;
use laminar_core::compiler::row::RowSchema;
use laminar_core::compiler::batch_reader::BatchRowReader;

let schema = Arc::new(Schema::new(vec![
    Field::new("ts", DataType::Int64, false),
    Field::new("val", DataType::Float64, true),
]));
let batch = RecordBatch::try_new(
    Arc::clone(&schema),
    vec![
        Arc::new(Int64Array::from(vec![1000, 2000])),
        Arc::new(Float64Array::from(vec![Some(1.5), None])),
    ],
).unwrap();

let row_schema = RowSchema::from_arrow(&schema).unwrap();
let reader = BatchRowReader::new(&batch, &row_schema);
assert_eq!(reader.row_count(), 2);

let arena = Bump::new();
let row0 = reader.read_row(0, &arena);
assert_eq!(row0.get_i64(0), 1000);
assert!(!row0.is_null(1));

let row1 = reader.read_row(1, &arena);
assert!(row1.is_null(1));

Structs

BatchRowReader

Reads rows from an Arrow [RecordBatch] into EventRow format.