Module predicate 

Predicate types for lookup table query pushdown.

These types represent filter predicates that can be pushed down to LookupSource implementations. Sources that support predicate pushdown can filter data at the source, reducing network and deserialization costs.

Pushdown Flow

1. SQL planner extracts WHERE predicates from a lookup join
2. split_predicates classifies each predicate as pushable or local
3. Pushable predicates are sent to the source via LookupSource::query()
4. Local predicates are applied after fetching results

Structs

SourceCapabilities

Capabilities that a lookup source declares for predicate pushdown.

SplitPredicates

Result of splitting predicates into pushable and local sets.

Enums

Predicate

A filter predicate for lookup table queries.

ScalarValue

A scalar value used in predicate evaluation.

Functions

predicate_to_sql

Convert a predicate to a SQL WHERE clause fragment.

split_predicates

Classify predicates as pushable or local based on source capabilities.