Module multi_property 

Utilities for managing and querying multi-properties.

A multi-property is a derived property composed of a tuple of other properties. They are primarily used to enable joint indexing and efficient multi-column style queries.

Normalization

To ensure that queries can efficiently find matching indexes, multi-properties that consist of the same set of component properties are considered equivalent, regardless of their definition order. Component properties are sorted alphabetically by property name to produce a canonical identity for that unordered component set. A query with the same component set can then resolve to the index (if it exists) of an equivalent (multi-)property regardless of the order client code provides the component values.

Query Integration

The querying subsystem uses the utilities in this module to detect when a query involving multiple individual properties can be satisfied by an existing multi-property index. If a match is found, the query can perform a fast index lookup instead of iterating over component properties.

Implementation Details

Multi-properties are defined using the define_multi_property! macro, which handles the registration and mapping between the property set and its representative property ID. This module provides the runtime registries and reordering logic used by both the macro-generated code and the query engine.

Functions

register_type_ids_to_multi_property_id

Registers the representative multi-property ID for an unordered component set.

static_apply_reordering

Reorders the values in place according to the ordering defined by indices. The indices is an ordering produced by sorted_indices/static_sorted_indices and encodes the sorted order of the keys (the names of the tag types).

static_inverse_indices

Returns the inverse of a reordering produced by static_sorted_indices.

static_reorder_by_keys

Reorder values in place according to the sorted order of keys.

static_sorted_indices

Returns the indices of keys in sorted order. These indices are used to reorder some other array according to the sorted order of the keys, e.g. by static_apply_reordering.

type_ids_to_multi_property_id

Looks up the representative multi-property ID for a sorted list of component TypeIds.