Module filter 

Filter pushdown support for Zarr queries

This module parses DataFusion filter expressions to extract coordinate equality filters (e.g., time = 1323647), which can be used to read only the relevant subset of Zarr arrays.

For a Zarr store with coordinates [time, hybrid, lat, lon], a filter like time = X AND hybrid = Y allows us to read only the slice of data where those coordinates match, dramatically reducing memory usage.

Structs

CoordFilter

Represents a parsed coordinate filter

CoordFilters

Collection of coordinate filters extracted from a WHERE clause

Enums

CoordValuesRef

Reference to coordinate values for searching

Functions

calculate_coord_ranges

Calculate which indices to read from each coordinate based on filters

calculate_filtered_rows

Calculate the total number of rows after applying coordinate filters

coord_ranges_to_array_ranges

Calculate Zarr array subset ranges from coordinate filter ranges

parse_coord_filters

Parse DataFusion filter expressions to extract coordinate equality filters