R*-tree Index

The R*-tree is the spatial engine's primary index. It supports range queries, nearest neighbor search, and spatial predicate evaluation.

Creating a Spatial Index

-- Automatic via SPATIAL_INDEX column modifier
CREATE COLLECTION locations TYPE COLUMNAR (
    geom GEOMETRY SPATIAL_INDEX,
    name VARCHAR
);

-- Or add to any collection
CREATE SPATIAL INDEX ON restaurants FIELDS location;

Operations

• Range query — ST_DWithin, ST_Within, ST_Intersects
• Nearest neighbor — ORDER BY ST_Distance(geom, point) LIMIT k
• Bulk load — Optimized for batch inserts
• Spatial join — R*-tree probe join between two collections

Query Execution

When a spatial predicate is present, the R*-tree narrows the candidate set before the columnar sparse index does final refinement. Queries without spatial predicates read directly from the columnar memtable — the R*-tree is not involved.

-- R*-tree lookup → sparse refinement → result
SELECT name FROM locations WHERE ST_DWithin(geom, ST_Point(-73.98, 40.75), 500);

-- No spatial predicate → direct columnar scan
SELECT name FROM locations WHERE name LIKE 'Park%';