Module iterator 

Iterator-based query execution pipeline.

This module provides an iterator-based execution model for SQL queries, enabling streaming execution and reduced memory usage for large datasets.

Architecture

The execution pipeline is built from composable iterators:

• ScanIterator: Reads rows from storage
• FilterIterator: Filters rows based on predicates
• SortIterator: Sorts rows (requires materialization)
• LimitIterator: Applies LIMIT/OFFSET constraints

Each iterator implements the RowIterator trait, allowing them to be composed into a pipeline that processes rows one at a time.

Structs

FilterIterator

Iterator that filters rows based on a predicate expression.

LimitIterator

Iterator that applies LIMIT and OFFSET constraints.

ScanIterator

Iterator that reads rows from table storage.

SortIterator

Iterator that sorts rows according to ORDER BY expressions.

VecIterator

Iterator that wraps a Vec<Row> for testing and compatibility.

Traits

RowIterator

A trait for row-producing iterators in the query execution pipeline.