another attempt to use the index 2

Author: jdkent

store/backend/neurostore/resources/data.py

@@ -617,9 +617,9 @@ def ann_query_object(
             embedding_expr = PipelineEmbedding.embedding
 
         distance_expr = embedding_expr.op("<=>")(qvec)
-        distance = distance_expr.label("distance")
+        distance = sa.cast(distance_expr, sa.Float).label("distance")
 
-        # Build the ANN CTE
+        # Build the ANN subquery
         inner = (
             sa.select(
                 PipelineEmbedding.base_study_id,
@@ -638,7 +638,7 @@ def ann_query_object(
         q = (
             q.with_entities(BaseStudy)
             .join(nearest, BaseStudy.id == nearest.c.base_study_id)
-            .filter(sa.cast(nearest.c.distance, sa.Float) < thr)
+            .filter(nearest.c.distance < thr)
             .order_by(nearest.c.distance)
             .params(
                 qvec=qvec_value,