Efficient cone searches with Healpix-alchemy

[BOAS]

TL;DR

Implementation of a more efficient cone search using healpix-alchemy

I am trying to implement a cone search for a catalog with the HEALPix-alchemy package. I have the following models set up, based on the examples here: https://arxiv.org/pdf/2112.06947

class Field(Base):
        """
        Represents a collection of FieldTiles making up the area of interest.
        """
        id = Column(Integer, primary_key=True, autoincrement=True)
        tiles = relationship(lambda: FieldTile, order_by="FieldTile.id")


class FieldTile(Base):
    """
    A HEALPix tile that is a component of the Field being selected.
    """
    id = Column(ForeignKey(Field.id), primary_key=True)
    hpx = Column(Tile, index=True)
    pk = Column(Integer, primary_key=True, autoincrement=True)


class Source(Base):
    """
    Represents a source and its location.
    """
   
    id = mapped_column(Integer, primary_key=True, index=True, autoincrement=True)
    name = Column(String, unique=True)
    Heal_Pix_Position = Column(Point, index=True, nullable=False)

I am then using CDSHealpix to get the HEALPix cells contained within a specified cone.

I construct the Multi Order Coverage map from the HEALPix cells using MOCpy and extract the HEALPix tiles using HEALPix-alchemy.

I then populate the Field table with this collection of tiles.

Finally, I perform the following query:

query = db.query(Source).filter(FieldTile.hpx.contains(Source.Heal_Pix_Position)).all()

However, this is very inefficient as I am effectively checking each source in my catalog to see if it is contained within a FieldTile.

How can I modify my approach so that I am checking each tile and returning the sources that it contains?