feat(python)!: support inserting and upserting subschemas (#1965)

BREAKING CHANGE: For a field "vector", list of integers will now be converted to binary (uint8) vectors instead of f32 vectors. Use float values instead for f32 vectors. * Adds proper support for inserting and upserting subsets of the full schema. I thought I had previously implemented this in #1827, but it turns out I had not tested carefully enough. * Refactors `_santize_data` and other utility functions to be simpler and not require `numpy` or `combine_chunks()`. * Added a new suite of unit tests to validate sanitization utilities. ## Examples ```python import pandas as pd import lancedb db = lancedb.connect("memory://demo") intial_data = pd.DataFrame({ "a": [1, 2, 3], "b": [4, 5, 6], "c": [7, 8, 9] }) table = db.create_table("demo", intial_data) # Insert a subschema new_data = pd.DataFrame({"a": [10, 11]}) table.add(new_data) table.to_pandas() ``` ``` a b c 0 1 4.0 7.0 1 2 5.0 8.0 2 3 6.0 9.0 3 10 NaN NaN 4 11 NaN NaN ``` ```python # Upsert a subschema upsert_data = pd.DataFrame({ "a": [3, 10, 15], "b": [6, 7, 8], }) table.merge_insert(on="a").when_matched_update_all().when_not_matched_insert_all().execute(upsert_data) table.to_pandas() ``` ``` a b c 0 1 4.0 7.0 1 2 5.0 8.0 2 3 6.0 9.0 3 10 7.0 NaN 4 11 NaN NaN 5 15 8.0 NaN ```
2026-01-02 18:02:58 +00:00 · 2025-01-08 10:11:10 -08:00
parent 3c0a64be8f
commit c557e77f09
10 changed files with 874 additions and 292 deletions
--- a/python/python/lancedb/db.py
+++ b/python/python/lancedb/db.py
@@ -784,10 +784,6 @@ class AsyncConnection(object):
            registry = EmbeddingFunctionRegistry.get_instance()
            metadata = registry.get_table_metadata(embedding_functions)

-        data, schema = sanitize_create_table(
-            data, schema, metadata, on_bad_vectors, fill_value
-        )
-
        # Defining defaults here and not in function prototype.  In the future
        # these defaults will move into rust so better to keep them as None.
        if on_bad_vectors is None:
--- a/python/python/lancedb/embeddings/registry.py
+++ b/python/python/lancedb/embeddings/registry.py
@@ -108,9 +108,14 @@ class EmbeddingFunctionRegistry:
            An empty dict is returned if input is None or does not
            contain b"embedding_functions".
        """
-        if metadata is None or b"embedding_functions" not in metadata:
+        if metadata is None:
+            return {}
+        # Look at both bytes and string keys, since we might use either
+        serialized = metadata.get(
+            b"embedding_functions", metadata.get("embedding_functions")
+        )
+        if serialized is None:
            return {}
-        serialized = metadata[b"embedding_functions"]
        raw_list = json.loads(serialized.decode("utf-8"))
        return {
            obj["vector_column"]: EmbeddingFunctionConfig(
--- a/python/python/lancedb/query.py
+++ b/python/python/lancedb/query.py
@@ -472,7 +472,7 @@ class LanceQueryBuilder(ABC):
        --------
        >>> import lancedb
        >>> db = lancedb.connect("./.lancedb")
-        >>> table = db.create_table("my_table", [{"vector": [99, 99]}])
+        >>> table = db.create_table("my_table", [{"vector": [99.0, 99]}])
        >>> query = [100, 100]
        >>> plan = table.search(query).explain_plan(True)
        >>> print(plan) # doctest: +ELLIPSIS, +NORMALIZE_WHITESPACE
--- a/python/python/lancedb/table.py
+++ b/python/python/lancedb/table.py
@@ -25,7 +25,6 @@ from urllib.parse import urlparse
 import lance
 from lancedb.background_loop import LOOP
 from .dependencies import _check_for_pandas
-import numpy as np
 import pyarrow as pa
 import pyarrow.compute as pc
 import pyarrow.fs as pa_fs
@@ -74,34 +73,17 @@ pl = safe_import_polars()
 QueryType = Literal["vector", "fts", "hybrid", "auto"]


-def _pd_schema_without_embedding_funcs(
-    schema: Optional[pa.Schema], columns: List[str]
-) -> Optional[pa.Schema]:
-    """Return a schema without any embedding function columns"""
-    if schema is None:
-        return None
-    embedding_functions = EmbeddingFunctionRegistry.get_instance().parse_functions(
-        schema.metadata
-    )
-    if not embedding_functions:
-        return schema
-    return pa.schema([field for field in schema if field.name in columns])
-
-
-def _coerce_to_table(data, schema: Optional[pa.Schema] = None) -> pa.Table:
+def _into_pyarrow_table(data) -> pa.Table:
    if _check_for_hugging_face(data):
        # Huggingface datasets
        from lance.dependencies import datasets

        if isinstance(data, datasets.Dataset):
-            if schema is None:
-                schema = data.features.arrow_schema
+            schema = data.features.arrow_schema
            return pa.Table.from_batches(data.data.to_batches(), schema=schema)
        elif isinstance(data, datasets.dataset_dict.DatasetDict):
-            if schema is None:
-                schema = _schema_from_hf(data, schema)
+            schema = _schema_from_hf(data, schema)
            return pa.Table.from_batches(_to_batches_with_split(data), schema=schema)
-
    if isinstance(data, LanceModel):
        raise ValueError("Cannot add a single LanceModel to a table. Use a list.")

@@ -111,17 +93,15 @@ def _coerce_to_table(data, schema: Optional[pa.Schema] = None) -> pa.Table:
    if isinstance(data, list):
        # convert to list of dict if data is a bunch of LanceModels
        if isinstance(data[0], LanceModel):
-            if schema is None:
-                schema = data[0].__class__.to_arrow_schema()
+            schema = data[0].__class__.to_arrow_schema()
            data = [model_to_dict(d) for d in data]
            return pa.Table.from_pylist(data, schema=schema)
        elif isinstance(data[0], pa.RecordBatch):
-            return pa.Table.from_batches(data, schema=schema)
+            return pa.Table.from_batches(data)
        else:
-            return pa.Table.from_pylist(data, schema=schema)
-    elif _check_for_pandas(data) and isinstance(data, pd.DataFrame):  # type: ignore
-        raw_schema = _pd_schema_without_embedding_funcs(schema, data.columns.to_list())
-        table = pa.Table.from_pandas(data, preserve_index=False, schema=raw_schema)
+            return pa.Table.from_pylist(data)
+    elif _check_for_pandas(data) and isinstance(data, pd.DataFrame):
+        table = pa.Table.from_pandas(data, preserve_index=False)
        # Do not serialize Pandas metadata
        meta = table.schema.metadata if table.schema.metadata is not None else {}
        meta = {k: v for k, v in meta.items() if k != b"pandas"}
@@ -143,8 +123,13 @@ def _coerce_to_table(data, schema: Optional[pa.Schema] = None) -> pa.Table:
        and data.__class__.__name__ == "DataFrame"
    ):
        return data.to_arrow()
+    elif (
+        type(data).__module__.startswith("polars")
+        and data.__class__.__name__ == "LazyFrame"
+    ):
+        return data.collect().to_arrow()
    elif isinstance(data, Iterable):
-        return _process_iterator(data, schema)
+        return _iterator_to_table(data)
    else:
        raise TypeError(
            f"Unknown data type {type(data)}. "
@@ -154,27 +139,172 @@ def _coerce_to_table(data, schema: Optional[pa.Schema] = None) -> pa.Table:
        )


+def _iterator_to_table(data: Iterable) -> pa.Table:
+    batches = []
+    schema = None  # Will get schema from first batch
+    for batch in data:
+        batch_table = _into_pyarrow_table(batch)
+        if schema is not None:
+            if batch_table.schema != schema:
+                try:
+                    batch_table = batch_table.cast(schema)
+                except pa.lib.ArrowInvalid:
+                    raise ValueError(
+                        f"Input iterator yielded a batch with schema that "
+                        f"does not match the schema of other batches.\n"
+                        f"Expected:\n{schema}\nGot:\n{batch_table.schema}"
+                    )
+        else:
+            # Use the first schema for the remainder of the batches
+            schema = batch_table.schema
+        batches.append(batch_table)
+
+    if batches:
+        return pa.concat_tables(batches)
+    else:
+        raise ValueError("Input iterable is empty")
+
+
 def _sanitize_data(
-    data: Any,
-    schema: Optional[pa.Schema] = None,
+    data: "DATA",
+    target_schema: Optional[pa.Schema] = None,
    metadata: Optional[dict] = None,  # embedding metadata
-    on_bad_vectors: str = "error",
+    on_bad_vectors: Literal["error", "drop", "fill", "null"] = "error",
    fill_value: float = 0.0,
-) -> Tuple[pa.Table, pa.Schema]:
-    data = _coerce_to_table(data, schema)
+    *,
+    allow_subschema: bool = False,
+) -> pa.Table:
+    """
+    Handle input data, applying all standard transformations.
+
+    This includes:
+
+     * Converting the data to a PyArrow Table
+     * Adding vector columns defined in the metadata
+     * Adding embedding metadata into the schema
+     * Casting the table to the target schema
+     * Handling bad vectors
+
+    Parameters
+    ----------
+    target_schema : Optional[pa.Schema], default None
+        The schema to cast the table to. This is typically the schema of the table
+        if it already exists. Otherwise it might be a user-requested schema.
+    allow_subschema : bool, default False
+        If True, the input table is allowed to omit columns from the target schema.
+        The target schema will be filtered to only include columns that are present
+        in the input table before casting.
+    metadata : Optional[dict], default None
+        The embedding metadata to add to the schema.
+    on_bad_vectors : Literal["error", "drop", "fill", "null"], default "error"
+        What to do if any of the vectors are not the same size or contains NaNs.
+    fill_value : float, default 0.0
+        The value to use when filling vectors. Only used if on_bad_vectors="fill".
+        All entries in the vector will be set to this value.
+    """
+    # At this point, the table might not match the schema we are targeting:
+    # 1. There might be embedding columns missing that will be added
+    #    in the add_embeddings step.
+    # 2. If `allow_subschemas` is True, there might be columns missing.
+    table = _into_pyarrow_table(data)
+
+    table = _append_vector_columns(table, target_schema, metadata=metadata)
+
+    # This happens before the cast so we can fix vector columns with
+    # incorrect lengths before they are cast to FSL.
+    table = _handle_bad_vectors(
+        table,
+        on_bad_vectors=on_bad_vectors,
+        fill_value=fill_value,
+    )
+
+    if target_schema is None:
+        target_schema = _infer_target_schema(table)

    if metadata:
-        data = _append_vector_col(data, metadata, schema)
-        metadata.update(data.schema.metadata or {})
-        data = data.replace_schema_metadata(metadata)
+        new_metadata = target_schema.metadata or {}
+        new_metadata = new_metadata.update(metadata)
+        target_schema = target_schema.with_metadata(new_metadata)

-    # TODO improve the logics in _sanitize_schema
-    data = _sanitize_schema(data, schema, on_bad_vectors, fill_value)
-    if schema is None:
-        schema = data.schema
+    _validate_schema(target_schema)

-    _validate_schema(schema)
-    return data, schema
+    table = _cast_to_target_schema(table, target_schema, allow_subschema)
+
+    return table
+
+
+def _cast_to_target_schema(
+    table: pa.Table,
+    target_schema: pa.Schema,
+    allow_subschema: bool = False,
+) -> pa.Table:
+    # pa.Table.cast expects field order not to be changed.
+    # Lance doesn't care about field order, so we don't need to rearrange fields
+    # to match the target schema. We just need to correctly cast the fields.
+    if table.schema == target_schema:
+        # Fast path when the schemas are already the same
+        return table
+
+    fields = []
+    for field in table.schema:
+        target_field = target_schema.field(field.name)
+        if target_field is None:
+            raise ValueError(f"Field {field.name} not found in target schema")
+        fields.append(target_field)
+    reordered_schema = pa.schema(fields, metadata=target_schema.metadata)
+    if not allow_subschema and len(reordered_schema) != len(target_schema):
+        raise ValueError(
+            "Input table has different number of columns than target schema"
+        )
+
+    if allow_subschema and len(reordered_schema) != len(target_schema):
+        fields = _infer_subschema(
+            list(iter(table.schema)), list(iter(reordered_schema))
+        )
+        subschema = pa.schema(fields, metadata=target_schema.metadata)
+        return table.cast(subschema)
+    else:
+        return table.cast(reordered_schema)
+
+
+def _infer_subschema(
+    schema: List[pa.Field],
+    reference_fields: List[pa.Field],
+) -> List[pa.Field]:
+    """
+    Transform the list of fields so the types match the reference_fields.
+
+    The order of the fields is preserved.
+
+    ``schema`` may have fewer fields than `reference_fields`, but it may not have
+    more fields.
+
+    """
+    fields = []
+    lookup = {f.name: f for f in reference_fields}
+    for field in schema:
+        reference = lookup.get(field.name)
+        if reference is None:
+            raise ValueError("Unexpected field in schema: {}".format(field))
+
+        if pa.types.is_struct(reference.type):
+            new_type = pa.struct(
+                _infer_subschema(
+                    field.type.fields,
+                    reference.type.fields,
+                )
+            )
+            new_field = pa.field(
+                field.name,
+                new_type,
+                reference.nullable,
+            )
+        else:
+            new_field = reference
+
+        fields.append(new_field)
+
+    return fields


 def sanitize_create_table(
@@ -193,13 +323,14 @@ def sanitize_create_table(
    if data is not None:
        if metadata is None and schema is not None:
            metadata = schema.metadata
-        data, schema = _sanitize_data(
+        data = _sanitize_data(
            data,
            schema,
            metadata=metadata,
            on_bad_vectors=on_bad_vectors,
            fill_value=fill_value,
        )
+        schema = data.schema
    else:
        if schema is not None:
            data = pa.Table.from_pylist([], schema)
@@ -211,6 +342,8 @@ def sanitize_create_table(

    if metadata:
        schema = schema.with_metadata(metadata)
+        # Need to apply metadata to the data as well
+        data = data.replace_schema_metadata(metadata)

    return data, schema

@@ -246,12 +379,22 @@ def _to_batches_with_split(data):
                yield b


-def _append_vector_col(data: pa.Table, metadata: dict, schema: Optional[pa.Schema]):
+def _append_vector_columns(
+    data: pa.Table,
+    schema: Optional[pa.Schema] = None,
+    *,
+    metadata: Optional[dict] = None,
+) -> pa.Table:
    """
-    Use the embedding function to automatically embed the source column and add the
-    vector column to the table.
+    Use the embedding function to automatically embed the source columns and add the
+    vector columns to the table.
    """
+    if schema is None:
+        metadata = metadata or {}
+    else:
+        metadata = schema.metadata or metadata or {}
    functions = EmbeddingFunctionRegistry.get_instance().parse_functions(metadata)
+
    for vector_column, conf in functions.items():
        func = conf.function
        no_vector_column = vector_column not in data.column_names
@@ -790,9 +933,9 @@ class Table(ABC):
        --------
        >>> import lancedb
        >>> data = [
-        ...    {"x": 1, "vector": [1, 2]},
-        ...    {"x": 2, "vector": [3, 4]},
-        ...    {"x": 3, "vector": [5, 6]}
+        ...    {"x": 1, "vector": [1.0, 2]},
+        ...    {"x": 2, "vector": [3.0, 4]},
+        ...    {"x": 3, "vector": [5.0, 6]}
        ... ]
        >>> db = lancedb.connect("./.lancedb")
        >>> table = db.create_table("my_table", data)
@@ -854,7 +997,7 @@ class Table(ABC):
        --------
        >>> import lancedb
        >>> import pandas as pd
-        >>> data = pd.DataFrame({"x": [1, 2, 3], "vector": [[1, 2], [3, 4], [5, 6]]})
+        >>> data = pd.DataFrame({"x": [1, 2, 3], "vector": [[1.0, 2], [3, 4], [5, 6]]})
        >>> db = lancedb.connect("./.lancedb")
        >>> table = db.create_table("my_table", data)
        >>> table.to_pandas()
@@ -862,7 +1005,7 @@ class Table(ABC):
        0  1  [1.0, 2.0]
        1  2  [3.0, 4.0]
        2  3  [5.0, 6.0]
-        >>> table.update(where="x = 2", values={"vector": [10, 10]})
+        >>> table.update(where="x = 2", values={"vector": [10.0, 10]})
        >>> table.to_pandas()
           x        vector
        0  1    [1.0, 2.0]
@@ -1880,9 +2023,9 @@ class LanceTable(Table):
        --------
        >>> import lancedb
        >>> data = [
-        ...    {"x": 1, "vector": [1, 2]},
-        ...    {"x": 2, "vector": [3, 4]},
-        ...    {"x": 3, "vector": [5, 6]}
+        ...    {"x": 1, "vector": [1.0, 2]},
+        ...    {"x": 2, "vector": [3.0, 4]},
+        ...    {"x": 3, "vector": [5.0, 6]}
        ... ]
        >>> db = lancedb.connect("./.lancedb")
        >>> table = db.create_table("my_table", data)
@@ -1971,7 +2114,7 @@ class LanceTable(Table):
        --------
        >>> import lancedb
        >>> import pandas as pd
-        >>> data = pd.DataFrame({"x": [1, 2, 3], "vector": [[1, 2], [3, 4], [5, 6]]})
+        >>> data = pd.DataFrame({"x": [1, 2, 3], "vector": [[1.0, 2], [3, 4], [5, 6]]})
        >>> db = lancedb.connect("./.lancedb")
        >>> table = db.create_table("my_table", data)
        >>> table.to_pandas()
@@ -1979,7 +2122,7 @@ class LanceTable(Table):
        0  1  [1.0, 2.0]
        1  2  [3.0, 4.0]
        2  3  [5.0, 6.0]
-        >>> table.update(where="x = 2", values={"vector": [10, 10]})
+        >>> table.update(where="x = 2", values={"vector": [10.0, 10]})
        >>> table.to_pandas()
           x        vector
        0  1    [1.0, 2.0]
@@ -2165,74 +2308,49 @@ class LanceTable(Table):
        LOOP.run(self._table.migrate_v2_manifest_paths())


-def _sanitize_schema(
-    data: pa.Table,
-    schema: pa.Schema = None,
-    on_bad_vectors: str = "error",
+def _handle_bad_vectors(
+    table: pa.Table,
+    on_bad_vectors: Literal["error", "drop", "fill", "null"] = "error",
    fill_value: float = 0.0,
 ) -> pa.Table:
-    """Ensure that the table has the expected schema.
-
-    Parameters
-    ----------
-    data: pa.Table
-        The table to sanitize.
-    schema: pa.Schema; optional
-        The expected schema. If not provided, this just converts the
-        vector column to fixed_size_list(float32) if necessary.
-    on_bad_vectors: str, default "error"
-        What to do if any of the vectors are not the same size or contains NaNs.
-        One of "error", "drop", "fill", "null".
-    fill_value: float, default 0.
-        The value to use when filling vectors. Only used if on_bad_vectors="fill".
-    """
-    if schema is not None:
-        # cast the columns to the expected types
-        data = data.combine_chunks()
-        for field in schema:
-            # TODO: we're making an assumption that fixed size list of 10 or more
-            # is a vector column. This is definitely a bit hacky.
-            likely_vector_col = (
-                pa.types.is_fixed_size_list(field.type)
-                and pa.types.is_float32(field.type.value_type)
-                and field.type.list_size >= 10
+    for field in table.schema:
+        # They can provide a 'vector' column that isn't yet a FSL
+        named_vector_col = (
+            (
+                pa.types.is_list(field.type)
+                or pa.types.is_large_list(field.type)
+                or pa.types.is_fixed_size_list(field.type)
            )
-            is_default_vector_col = field.name == VECTOR_COLUMN_NAME
-            if field.name in data.column_names and (
-                likely_vector_col or is_default_vector_col
-            ):
-                data = _sanitize_vector_column(
-                    data,
-                    vector_column_name=field.name,
-                    on_bad_vectors=on_bad_vectors,
-                    fill_value=fill_value,
-                    table_schema=schema,
-                )
-        return pa.Table.from_arrays(
-            [data[name] for name in schema.names], schema=schema
+            and pa.types.is_floating(field.type.value_type)
+            and field.name == VECTOR_COLUMN_NAME
+        )
+        # TODO: we're making an assumption that fixed size list of 10 or more
+        # is a vector column. This is definitely a bit hacky.
+        likely_vector_col = (
+            pa.types.is_fixed_size_list(field.type)
+            and pa.types.is_floating(field.type.value_type)
+            and (field.type.list_size >= 10)
        )

-    # just check the vector column
-    if VECTOR_COLUMN_NAME in data.column_names:
-        return _sanitize_vector_column(
-            data,
-            vector_column_name=VECTOR_COLUMN_NAME,
-            on_bad_vectors=on_bad_vectors,
-            fill_value=fill_value,
-        )
+        if named_vector_col or likely_vector_col:
+            table = _handle_bad_vector_column(
+                table,
+                vector_column_name=field.name,
+                on_bad_vectors=on_bad_vectors,
+                fill_value=fill_value,
+            )

-    return data
+    return table


-def _sanitize_vector_column(
+def _handle_bad_vector_column(
    data: pa.Table,
    vector_column_name: str,
-    table_schema: Optional[pa.Schema] = None,
    on_bad_vectors: str = "error",
    fill_value: float = 0.0,
 ) -> pa.Table:
    """
-    Ensure that the vector column exists and has type fixed_size_list(float32)
+    Ensure that the vector column exists and has type fixed_size_list(float)

    Parameters
    ----------
@@ -2246,141 +2364,118 @@ def _sanitize_vector_column(
    fill_value: float, default 0.0
        The value to use when filling vectors. Only used if on_bad_vectors="fill".
    """
-    # ChunkedArray is annoying to work with, so we combine chunks here
-    vec_arr = data[vector_column_name].combine_chunks()
-    if table_schema is not None:
-        field = table_schema.field(vector_column_name)
-    else:
-        field = None
-    typ = data[vector_column_name].type
-    if pa.types.is_list(typ) or pa.types.is_large_list(typ):
-        # if it's a variable size list array,
-        # we make sure the dimensions are all the same
-        has_jagged_ndims = len(vec_arr.values) % len(data) != 0
-        if has_jagged_ndims:
-            data = _sanitize_jagged(
-                data, fill_value, on_bad_vectors, vec_arr, vector_column_name
-            )
-            vec_arr = data[vector_column_name].combine_chunks()
-        vec_arr = ensure_fixed_size_list(vec_arr)
-        data = data.set_column(
-            data.column_names.index(vector_column_name), vector_column_name, vec_arr
-        )
-    elif not pa.types.is_fixed_size_list(vec_arr.type):
-        raise TypeError(f"Unsupported vector column type: {vec_arr.type}")
+    vec_arr = data[vector_column_name]

-    if pa.types.is_float16(vec_arr.values.type):
-        # Use numpy to check for NaNs, because as pyarrow does not have `is_nan`
-        # kernel over f16 types yet.
-        values_np = vec_arr.values.to_numpy(zero_copy_only=True)
-        if np.isnan(values_np).any():
-            data = _sanitize_nans(
-                data, fill_value, on_bad_vectors, vec_arr, vector_column_name
-            )
-    else:
-        if (
-            field is not None
-            and not field.nullable
-            and pc.any(pc.is_null(vec_arr.values)).as_py()
-        ) or (pc.any(pc.is_nan(vec_arr.values)).as_py()):
-            data = _sanitize_nans(
-                data, fill_value, on_bad_vectors, vec_arr, vector_column_name
-            )
-    return data
+    has_nan = has_nan_values(vec_arr)

-
-def ensure_fixed_size_list(vec_arr) -> pa.FixedSizeListArray:
-    values = vec_arr.values
-    if not (pa.types.is_float16(values.type) or pa.types.is_float32(values.type)):
-        values = values.cast(pa.float32())
    if pa.types.is_fixed_size_list(vec_arr.type):
-        list_size = vec_arr.type.list_size
+        dim = vec_arr.type.list_size
    else:
-        list_size = len(values) / len(vec_arr)
-    vec_arr = pa.FixedSizeListArray.from_arrays(values, list_size)
-    return vec_arr
+        dim = _modal_list_size(vec_arr)
+    has_wrong_dim = pc.not_equal(pc.list_value_length(vec_arr), dim)

+    has_bad_vectors = pc.any(has_nan).as_py() or pc.any(has_wrong_dim).as_py()

-def _sanitize_jagged(data, fill_value, on_bad_vectors, vec_arr, vector_column_name):
-    """Sanitize jagged vectors."""
-    if on_bad_vectors == "error":
-        raise ValueError(
-            f"Vector column {vector_column_name} has variable length vectors "
-            "Set on_bad_vectors='drop' to remove them, or "
-            "set on_bad_vectors='fill' and fill_value=<value> to replace them."
-        )
-
-    lst_lengths = pc.list_value_length(vec_arr)
-    ndims = pc.max(lst_lengths).as_py()
-    correct_ndims = pc.equal(lst_lengths, ndims)
-
-    if on_bad_vectors == "fill":
-        if fill_value is None:
-            raise ValueError(
-                "`fill_value` must not be None if `on_bad_vectors` is 'fill'"
+    if has_bad_vectors:
+        is_bad = pc.or_(has_nan, has_wrong_dim)
+        if on_bad_vectors == "error":
+            if pc.any(has_wrong_dim).as_py():
+                raise ValueError(
+                    f"Vector column '{vector_column_name}' has variable length "
+                    "vectors. Set on_bad_vectors='drop' to remove them, "
+                    "set on_bad_vectors='fill' and fill_value=<value> to replace them, "
+                    "or set on_bad_vectors='null' to replace them with null."
+                )
+            else:
+                raise ValueError(
+                    f"Vector column '{vector_column_name}' has NaNs. "
+                    "Set on_bad_vectors='drop' to remove them, "
+                    "set on_bad_vectors='fill' and fill_value=<value> to replace them, "
+                    "or set on_bad_vectors='null' to replace them with null."
+                )
+        elif on_bad_vectors == "null":
+            vec_arr = pc.if_else(
+                is_bad,
+                pa.scalar(None),
+                vec_arr,
            )
-        fill_arr = pa.scalar([float(fill_value)] * ndims)
-        vec_arr = pc.if_else(correct_ndims, vec_arr, fill_arr)
-        data = data.set_column(
-            data.column_names.index(vector_column_name), vector_column_name, vec_arr
-        )
-    elif on_bad_vectors == "drop":
-        data = data.filter(correct_ndims)
-    elif on_bad_vectors == "null":
-        data = data.set_column(
-            data.column_names.index(vector_column_name),
-            vector_column_name,
-            pc.if_else(correct_ndims, vec_arr, pa.scalar(None)),
-        )
-    return data
-
-
-def _sanitize_nans(
-    data,
-    fill_value,
-    on_bad_vectors,
-    vec_arr: pa.FixedSizeListArray,
-    vector_column_name: str,
-):
-    """Sanitize NaNs in vectors"""
-    assert pa.types.is_fixed_size_list(vec_arr.type)
-    if on_bad_vectors == "error":
-        raise ValueError(
-            f"Vector column {vector_column_name} has NaNs. "
-            "Set on_bad_vectors='drop' to remove them, or "
-            "set on_bad_vectors='fill' and fill_value=<value> to replace them. "
-            "Or set on_bad_vectors='null' to replace them with null."
-        )
-    elif on_bad_vectors == "fill":
-        if fill_value is None:
-            raise ValueError(
-                "`fill_value` must not be None if `on_bad_vectors` is 'fill'"
+        elif on_bad_vectors == "drop":
+            data = data.filter(pc.invert(is_bad))
+            vec_arr = data[vector_column_name]
+        elif on_bad_vectors == "fill":
+            if fill_value is None:
+                raise ValueError(
+                    "`fill_value` must not be None if `on_bad_vectors` is 'fill'"
+                )
+            vec_arr = pc.if_else(
+                is_bad,
+                pa.scalar([fill_value] * dim),
+                vec_arr,
            )
-        fill_value = float(fill_value)
-        values = pc.if_else(pc.is_nan(vec_arr.values), fill_value, vec_arr.values)
-        ndims = len(vec_arr[0])
-        vec_arr = pa.FixedSizeListArray.from_arrays(values, ndims)
-        data = data.set_column(
-            data.column_names.index(vector_column_name), vector_column_name, vec_arr
-        )
-    elif on_bad_vectors == "drop":
-        # Drop is very slow to be able to filter out NaNs in a fixed size list array
-        np_arr = np.isnan(vec_arr.values.to_numpy(zero_copy_only=False))
-        np_arr = np_arr.reshape(-1, vec_arr.type.list_size)
-        not_nulls = np.any(np_arr, axis=1)
-        data = data.filter(~not_nulls)
-    elif on_bad_vectors == "null":
-        # null = pa.nulls(len(vec_arr)).cast(vec_arr.type)
-        # values = pc.if_else(pc.is_nan(vec_arr.values), fill_value, vec_arr.values)
-        np_arr = np.isnan(vec_arr.values.to_numpy(zero_copy_only=False))
-        np_arr = np_arr.reshape(-1, vec_arr.type.list_size)
-        no_nans = np.any(np_arr, axis=1)
-        data = data.set_column(
-            data.column_names.index(vector_column_name),
-            vector_column_name,
-            pc.if_else(no_nans, vec_arr, pa.scalar(None)),
-        )
-    return data
+        else:
+            raise ValueError(f"Invalid value for on_bad_vectors: {on_bad_vectors}")
+
+    position = data.column_names.index(vector_column_name)
+    return data.set_column(position, vector_column_name, vec_arr)
+
+
+def has_nan_values(arr: Union[pa.ListArray, pa.ChunkedArray]) -> pa.BooleanArray:
+    if isinstance(arr, pa.ChunkedArray):
+        values = pa.chunked_array([chunk.flatten() for chunk in arr.chunks])
+    else:
+        values = arr.flatten()
+    if pa.types.is_float16(values.type):
+        # is_nan isn't yet implemented for f16, so we cast to f32
+        # https://github.com/apache/arrow/issues/45083
+        values_has_nan = pc.is_nan(values.cast(pa.float32()))
+    else:
+        values_has_nan = pc.is_nan(values)
+    values_indices = pc.list_parent_indices(arr)
+    has_nan_indices = pc.unique(pc.filter(values_indices, values_has_nan))
+    indices = pa.array(range(len(arr)), type=pa.uint32())
+    return pc.is_in(indices, has_nan_indices)
+
+
+def _infer_target_schema(table: pa.Table) -> pa.Schema:
+    schema = table.schema
+
+    for i, field in enumerate(schema):
+        if (
+            field.name == VECTOR_COLUMN_NAME
+            and (pa.types.is_list(field.type) or pa.types.is_large_list(field.type))
+            and pa.types.is_floating(field.type.value_type)
+        ):
+            # Use the most common length of the list as the dimensions
+            dim = _modal_list_size(table.column(i))
+
+            new_field = pa.field(
+                VECTOR_COLUMN_NAME,
+                pa.list_(pa.float32(), dim),
+                nullable=field.nullable,
+            )
+
+            schema = schema.set(i, new_field)
+        elif (
+            field.name == VECTOR_COLUMN_NAME
+            and (pa.types.is_list(field.type) or pa.types.is_large_list(field.type))
+            and pa.types.is_integer(field.type.value_type)
+        ):
+            # Use the most common length of the list as the dimensions
+            dim = _modal_list_size(table.column(i))
+            new_field = pa.field(
+                VECTOR_COLUMN_NAME,
+                pa.list_(pa.uint8(), dim),
+                nullable=field.nullable,
+            )
+
+            schema = schema.set(i, new_field)
+
+    return schema
+
+
+def _modal_list_size(arr: Union[pa.ListArray, pa.ChunkedArray]) -> int:
+    # Use the most common length of the list as the dimensions
+    return pc.mode(pc.list_value_length(arr))[0].as_py()["mode"]


 def _validate_schema(schema: pa.Schema):
@@ -2410,28 +2505,6 @@ def _validate_metadata(metadata: dict):
            _validate_metadata(v)


-def _process_iterator(data: Iterable, schema: Optional[pa.Schema] = None) -> pa.Table:
-    batches = []
-    for batch in data:
-        batch_table = _coerce_to_table(batch, schema)
-        if schema is not None:
-            if batch_table.schema != schema:
-                try:
-                    batch_table = batch_table.cast(schema)
-                except pa.lib.ArrowInvalid:  # type: ignore
-                    raise ValueError(
-                        f"Input iterator yielded a batch with schema that "
-                        f"does not match the expected schema.\nExpected:\n{schema}\n"
-                        f"Got:\n{batch_table.schema}"
-                    )
-        batches.append(batch_table)
-
-    if batches:
-        return pa.concat_tables(batches)
-    else:
-        raise ValueError("Input iterable is empty")
-
-
 class AsyncTable:
    """
    An AsyncTable is a collection of Records in a LanceDB Database.
@@ -2678,16 +2751,17 @@ class AsyncTable:
            on_bad_vectors = "error"
        if fill_value is None:
            fill_value = 0.0
-        table_and_schema: Tuple[pa.Table, pa.Schema] = _sanitize_data(
+        data = _sanitize_data(
            data,
            schema,
            metadata=schema.metadata,
            on_bad_vectors=on_bad_vectors,
            fill_value=fill_value,
+            allow_subschema=True,
        )
-        tbl, schema = table_and_schema
-        if isinstance(tbl, pa.Table):
-            data = pa.RecordBatchReader.from_batches(schema, tbl.to_batches())
+        if isinstance(data, pa.Table):
+            data = data.to_reader()
+
        await self._inner.add(data, mode or "append")

    def merge_insert(self, on: Union[str, Iterable[str]]) -> LanceMergeInsertBuilder:
@@ -2822,12 +2896,13 @@ class AsyncTable:
            on_bad_vectors = "error"
        if fill_value is None:
            fill_value = 0.0
-        data, _ = _sanitize_data(
+        data = _sanitize_data(
            new_data,
            schema,
            metadata=schema.metadata,
            on_bad_vectors=on_bad_vectors,
            fill_value=fill_value,
+            allow_subschema=True,
        )
        if isinstance(data, pa.Table):
            data = pa.RecordBatchReader.from_batches(data.schema, data.to_batches())
@@ -2862,9 +2937,9 @@ class AsyncTable:
        --------
        >>> import lancedb
        >>> data = [
-        ...    {"x": 1, "vector": [1, 2]},
-        ...    {"x": 2, "vector": [3, 4]},
-        ...    {"x": 3, "vector": [5, 6]}
+        ...    {"x": 1, "vector": [1.0, 2]},
+        ...    {"x": 2, "vector": [3.0, 4]},
+        ...    {"x": 3, "vector": [5.0, 6]}
        ... ]
        >>> db = lancedb.connect("./.lancedb")
        >>> table = db.create_table("my_table", data)
--- a/python/python/lancedb/util.py
+++ b/python/python/lancedb/util.py
@@ -223,9 +223,7 @@ def inf_vector_column_query(schema: pa.Schema) -> str:
    vector_col_count = 0
    for field_name in schema.names:
        field = schema.field(field_name)
-        if pa.types.is_fixed_size_list(field.type) and pa.types.is_floating(
-            field.type.value_type
-        ):
+        if pa.types.is_fixed_size_list(field.type):
            vector_col_count += 1
            if vector_col_count > 1:
                raise ValueError(
--- a/python/python/tests/docs/test_binary_vector.py
+++ b/python/python/tests/docs/test_binary_vector.py
@@ -21,7 +21,7 @@ def test_binary_vector():
    ]
    tbl = db.create_table("my_binary_vectors", data=data)
    query = np.random.randint(0, 256, size=16)
-    tbl.search(query).to_arrow()
+    tbl.search(query).metric("hamming").to_arrow()
    # --8<-- [end:sync_binary_vector]
    db.drop_table("my_binary_vectors")

@@ -39,6 +39,6 @@ async def test_binary_vector_async():
    ]
    tbl = await db.create_table("my_binary_vectors", data=data)
    query = np.random.randint(0, 256, size=16)
-    await tbl.query().nearest_to(query).to_arrow()
+    await tbl.query().nearest_to(query).distance_type("hamming").to_arrow()
    # --8<-- [end:async_binary_vector]
    await db.drop_table("my_binary_vectors")
--- a/python/python/tests/docs/test_guide_index.py
+++ b/python/python/tests/docs/test_guide_index.py
@@ -118,9 +118,9 @@ def test_scalar_index():
    # --8<-- [end:search_with_scalar_index]
    # --8<-- [start:vector_search_with_scalar_index]
    data = [
-        {"book_id": 1, "vector": [1, 2]},
-        {"book_id": 2, "vector": [3, 4]},
-        {"book_id": 3, "vector": [5, 6]},
+        {"book_id": 1, "vector": [1.0, 2]},
+        {"book_id": 2, "vector": [3.0, 4]},
+        {"book_id": 3, "vector": [5.0, 6]},
    ]

    table = db.create_table("book_with_embeddings", data)
@@ -156,9 +156,9 @@ async def test_scalar_index_async():
    # --8<-- [end:search_with_scalar_index_async]
    # --8<-- [start:vector_search_with_scalar_index_async]
    data = [
-        {"book_id": 1, "vector": [1, 2]},
-        {"book_id": 2, "vector": [3, 4]},
-        {"book_id": 3, "vector": [5, 6]},
+        {"book_id": 1, "vector": [1.0, 2]},
+        {"book_id": 2, "vector": [3.0, 4]},
+        {"book_id": 3, "vector": [5.0, 6]},
    ]
    async_tbl = await async_db.create_table("book_with_embeddings_async", data)
    (await async_tbl.query().where("book_id != 3").nearest_to([1, 2]).to_pandas())
--- a/python/python/tests/test_embeddings.py
+++ b/python/python/tests/test_embeddings.py
@@ -198,7 +198,6 @@ def test_embedding_function_with_pandas(tmp_path):
        {
            "text": ["hello world", "goodbye world"],
            "val": [1, 2],
-            "not-used": ["s1", "s3"],
        }
    )
    db = lancedb.connect(tmp_path)
@@ -212,7 +211,6 @@ def test_embedding_function_with_pandas(tmp_path):
        {
            "text": ["extra", "more"],
            "val": [4, 5],
-            "misc-col": ["s1", "s3"],
        }
    )
    tbl.add(df)
--- a/python/python/tests/test_table.py
+++ b/python/python/tests/test_table.py
@@ -242,8 +242,8 @@ def test_add_subschema(mem_db: DBConnection):

    data = {"price": 10.0, "item": "foo"}
    table.add([data])
-    data = {"price": 2.0, "vector": [3.1, 4.1]}
-    table.add([data])
+    data = pd.DataFrame({"price": [2.0], "vector": [[3.1, 4.1]]})
+    table.add(data)
    data = {"price": 3.0, "vector": [5.9, 26.5], "item": "bar"}
    table.add([data])

@@ -259,7 +259,7 @@ def test_add_subschema(mem_db: DBConnection):

    data = {"item": "foo"}
    # We can't omit a column if it's not nullable
-    with pytest.raises(RuntimeError, match="Invalid user input"):
+    with pytest.raises(RuntimeError, match="Append with different schema"):
        table.add([data])

    # We can add it if we make the column nullable
@@ -292,6 +292,7 @@ def test_add_nullability(mem_db: DBConnection):
        ]
    )
    table = mem_db.create_table("test", schema=schema)
+    assert table.schema.field("vector").nullable is False

    nullable_schema = pa.schema(
        [
@@ -320,7 +321,10 @@ def test_add_nullability(mem_db: DBConnection):
        schema=nullable_schema,
    )
    # We can't add nullable schema if it contains nulls
-    with pytest.raises(Exception, match="Vector column vector has NaNs"):
+    with pytest.raises(
+        Exception,
+        match="Casting field 'vector' with null values to non-nullable",
+    ):
        table.add(data)

    # But we can make it nullable
@@ -776,6 +780,38 @@ def test_merge_insert(mem_db: DBConnection):
    assert table.to_arrow().sort_by("a") == expected


+# We vary the data format because there are slight differences in how
+# subschemas are handled in different formats
+@pytest.mark.parametrize(
+    "data_format",
+    [
+        lambda table: table,
+        lambda table: table.to_pandas(),
+        lambda table: table.to_pylist(),
+    ],
+    ids=["pa.Table", "pd.DataFrame", "rows"],
+)
+def test_merge_insert_subschema(mem_db: DBConnection, data_format):
+    initial_data = pa.table(
+        {"id": range(3), "a": [1.0, 2.0, 3.0], "c": ["x", "x", "x"]}
+    )
+    table = mem_db.create_table("my_table", data=initial_data)
+
+    new_data = pa.table({"id": [2, 3], "c": ["y", "y"]})
+    new_data = data_format(new_data)
+    (
+        table.merge_insert(on="id")
+        .when_matched_update_all()
+        .when_not_matched_insert_all()
+        .execute(new_data)
+    )
+
+    expected = pa.table(
+        {"id": [0, 1, 2, 3], "a": [1.0, 2.0, 3.0, None], "c": ["x", "x", "y", "y"]}
+    )
+    assert table.to_arrow().sort_by("id") == expected
+
+
@pytest.mark.asyncio
 async def test_merge_insert_async(mem_db_async: AsyncConnection):
    data = pa.table({"a": [1, 2, 3], "b": ["a", "b", "c"]})
--- a/python/python/tests/test_util.py
+++ b/python/python/tests/test_util.py
@@ -13,10 +13,27 @@

 import os
 import pathlib
+from typing import Optional

+import lance
+from lancedb.conftest import MockTextEmbeddingFunction
+from lancedb.embeddings.base import EmbeddingFunctionConfig
+from lancedb.embeddings.registry import EmbeddingFunctionRegistry
+from lancedb.table import (
+    _append_vector_columns,
+    _cast_to_target_schema,
+    _handle_bad_vectors,
+    _into_pyarrow_table,
+    _sanitize_data,
+    _infer_target_schema,
+)
+import pyarrow as pa
+import pandas as pd
+import polars as pl
 import pytest
 import lancedb
 from lancedb.util import get_uri_scheme, join_uri, value_to_sql
+from utils import exception_output


 def test_normalize_uri():
@@ -111,3 +128,460 @@ def test_value_to_sql_string(tmp_path):
    for value in values:
        table.update(where=f"search = {value_to_sql(value)}", values={"replace": value})
        assert table.to_pandas().query("search == @value")["replace"].item() == value
+
+
+def test_append_vector_columns():
+    registry = EmbeddingFunctionRegistry.get_instance()
+    registry.register("test")(MockTextEmbeddingFunction)
+    conf = EmbeddingFunctionConfig(
+        source_column="text",
+        vector_column="vector",
+        function=MockTextEmbeddingFunction(),
+    )
+    metadata = registry.get_table_metadata([conf])
+
+    schema = pa.schema(
+        {
+            "text": pa.string(),
+            "vector": pa.list_(pa.float64(), 10),
+        }
+    )
+    data = pa.table(
+        {
+            "text": ["hello"],
+            "vector": [None],  # Replaces null
+        },
+        schema=schema,
+    )
+    output = _append_vector_columns(
+        data,
+        schema,  # metadata passed separate from schema
+        metadata=metadata,
+    )
+    assert output.schema == schema
+    assert output["vector"].null_count == 0
+
+    # Adds if missing
+    data = pa.table({"text": ["hello"]})
+    output = _append_vector_columns(
+        data,
+        schema.with_metadata(metadata),
+    )
+    assert output.schema == schema
+    assert output["vector"].null_count == 0
+
+    # doesn't embed if already there
+    data = pa.table(
+        {
+            "text": ["hello"],
+            "vector": [[42.0] * 10],
+        },
+        schema=schema,
+    )
+    output = _append_vector_columns(
+        data,
+        schema.with_metadata(metadata),
+    )
+    assert output == data  # No change
+
+    # No provided schema
+    data = pa.table(
+        {
+            "text": ["hello"],
+        }
+    )
+    output = _append_vector_columns(
+        data,
+        metadata=metadata,
+    )
+    expected_schema = pa.schema(
+        {
+            "text": pa.string(),
+            "vector": pa.list_(pa.float32(), 10),
+        }
+    )
+    assert output.schema == expected_schema
+    assert output["vector"].null_count == 0
+
+
+@pytest.mark.parametrize("on_bad_vectors", ["error", "drop", "fill", "null"])
+def test_handle_bad_vectors_jagged(on_bad_vectors):
+    vector = pa.array([[1.0, 2.0], [3.0], [4.0, 5.0]])
+    schema = pa.schema({"vector": pa.list_(pa.float64())})
+    data = pa.table({"vector": vector}, schema=schema)
+
+    if on_bad_vectors == "error":
+        with pytest.raises(ValueError) as e:
+            output = _handle_bad_vectors(
+                data,
+                on_bad_vectors=on_bad_vectors,
+            )
+        output = exception_output(e)
+        assert output == (
+            "ValueError: Vector column 'vector' has variable length vectors. Set "
+            "on_bad_vectors='drop' to remove them, set on_bad_vectors='fill' "
+            "and fill_value=<value> to replace them, or set on_bad_vectors='null' "
+            "to replace them with null."
+        )
+        return
+    else:
+        output = _handle_bad_vectors(
+            data,
+            on_bad_vectors=on_bad_vectors,
+            fill_value=42.0,
+        )
+
+    if on_bad_vectors == "drop":
+        expected = pa.array([[1.0, 2.0], [4.0, 5.0]])
+    elif on_bad_vectors == "fill":
+        expected = pa.array([[1.0, 2.0], [42.0, 42.0], [4.0, 5.0]])
+    elif on_bad_vectors == "null":
+        expected = pa.array([[1.0, 2.0], None, [4.0, 5.0]])
+
+    assert output["vector"].combine_chunks() == expected
+
+
+@pytest.mark.parametrize("on_bad_vectors", ["error", "drop", "fill", "null"])
+def test_handle_bad_vectors_nan(on_bad_vectors):
+    vector = pa.array([[1.0, float("nan")], [3.0, 4.0]])
+    data = pa.table({"vector": vector})
+
+    if on_bad_vectors == "error":
+        with pytest.raises(ValueError) as e:
+            output = _handle_bad_vectors(
+                data,
+                on_bad_vectors=on_bad_vectors,
+            )
+        output = exception_output(e)
+        assert output == (
+            "ValueError: Vector column 'vector' has NaNs. Set "
+            "on_bad_vectors='drop' to remove them, set on_bad_vectors='fill' "
+            "and fill_value=<value> to replace them, or set on_bad_vectors='null' "
+            "to replace them with null."
+        )
+        return
+    else:
+        output = _handle_bad_vectors(
+            data,
+            on_bad_vectors=on_bad_vectors,
+            fill_value=42.0,
+        )
+
+    if on_bad_vectors == "drop":
+        expected = pa.array([[3.0, 4.0]])
+    elif on_bad_vectors == "fill":
+        expected = pa.array([[42.0, 42.0], [3.0, 4.0]])
+    elif on_bad_vectors == "null":
+        expected = pa.array([None, [3.0, 4.0]])
+
+    assert output["vector"].combine_chunks() == expected
+
+
+def test_handle_bad_vectors_noop():
+    # ChunkedArray should be preserved as-is
+    vector = pa.chunked_array(
+        [[[1.0, 2.0], [3.0, 4.0]]], type=pa.list_(pa.float64(), 2)
+    )
+    data = pa.table({"vector": vector})
+    output = _handle_bad_vectors(data)
+    assert output["vector"] == vector
+
+
+class TestModel(lancedb.pydantic.LanceModel):
+    a: Optional[int]
+    b: Optional[int]
+
+
+# TODO: huggingface,
+@pytest.mark.parametrize(
+    "data",
+    [
+        lambda: [{"a": 1, "b": 2}],
+        lambda: pa.RecordBatch.from_pylist([{"a": 1, "b": 2}]),
+        lambda: pa.table({"a": [1], "b": [2]}),
+        lambda: pa.table({"a": [1], "b": [2]}).to_reader(),
+        lambda: iter(pa.table({"a": [1], "b": [2]}).to_batches()),
+        lambda: (
+            lance.write_dataset(
+                pa.table({"a": [1], "b": [2]}),
+                "memory://test",
+            )
+        ),
+        lambda: (
+            lance.write_dataset(
+                pa.table({"a": [1], "b": [2]}),
+                "memory://test",
+            ).scanner()
+        ),
+        lambda: pd.DataFrame({"a": [1], "b": [2]}),
+        lambda: pl.DataFrame({"a": [1], "b": [2]}),
+        lambda: pl.LazyFrame({"a": [1], "b": [2]}),
+        lambda: [TestModel(a=1, b=2)],
+    ],
+    ids=[
+        "rows",
+        "pa.RecordBatch",
+        "pa.Table",
+        "pa.RecordBatchReader",
+        "batch_iter",
+        "lance.LanceDataset",
+        "lance.LanceScanner",
+        "pd.DataFrame",
+        "pl.DataFrame",
+        "pl.LazyFrame",
+        "pydantic",
+    ],
+)
+def test_into_pyarrow_table(data):
+    expected = pa.table({"a": [1], "b": [2]})
+    output = _into_pyarrow_table(data())
+    assert output == expected
+
+
+def test_infer_target_schema():
+    example = pa.schema(
+        {
+            "vec1": pa.list_(pa.float64(), 2),
+            "vector": pa.list_(pa.float64()),
+        }
+    )
+    data = pa.table(
+        {
+            "vec1": [[0.0] * 2],
+            "vector": [[0.0] * 2],
+        },
+        schema=example,
+    )
+    expected = pa.schema(
+        {
+            "vec1": pa.list_(pa.float64(), 2),
+            "vector": pa.list_(pa.float32(), 2),
+        }
+    )
+    output = _infer_target_schema(data)
+    assert output == expected
+
+    # Handle large list and use modal size
+    # Most vectors are of length 2, so we should infer that as the target dimension
+    example = pa.schema(
+        {
+            "vector": pa.large_list(pa.float64()),
+        }
+    )
+    data = pa.table(
+        {
+            "vector": [[0.0] * 2, [0.0], [0.0] * 2],
+        },
+        schema=example,
+    )
+    expected = pa.schema(
+        {
+            "vector": pa.list_(pa.float32(), 2),
+        }
+    )
+    output = _infer_target_schema(data)
+    assert output == expected
+
+    # ignore if not list
+    example = pa.schema(
+        {
+            "vector": pa.float64(),
+        }
+    )
+    data = pa.table(
+        {
+            "vector": [0.0],
+        },
+        schema=example,
+    )
+    expected = example
+    output = _infer_target_schema(data)
+    assert output == expected
+
+
+@pytest.mark.parametrize(
+    "data",
+    [
+        [{"id": 1, "text": "hello"}],
+        pa.RecordBatch.from_pylist([{"id": 1, "text": "hello"}]),
+        pd.DataFrame({"id": [1], "text": ["hello"]}),
+        pl.DataFrame({"id": [1], "text": ["hello"]}),
+    ],
+    ids=["rows", "pa.RecordBatch", "pd.DataFrame", "pl.DataFrame"],
+)
+@pytest.mark.parametrize(
+    "schema",
+    [
+        None,
+        pa.schema(
+            {
+                "id": pa.int32(),
+                "text": pa.string(),
+                "vector": pa.list_(pa.float32(), 10),
+            }
+        ),
+        pa.schema(
+            {
+                "id": pa.int64(),
+                "text": pa.string(),
+                "vector": pa.list_(pa.float32(), 10),
+                "extra": pa.int64(),
+            }
+        ),
+    ],
+    ids=["infer", "explicit", "subschema"],
+)
+@pytest.mark.parametrize("with_embedding", [True, False])
+def test_sanitize_data(
+    data,
+    schema: Optional[pa.Schema],
+    with_embedding: bool,
+):
+    if with_embedding:
+        registry = EmbeddingFunctionRegistry.get_instance()
+        registry.register("test")(MockTextEmbeddingFunction)
+        conf = EmbeddingFunctionConfig(
+            source_column="text",
+            vector_column="vector",
+            function=MockTextEmbeddingFunction(),
+        )
+        metadata = registry.get_table_metadata([conf])
+    else:
+        metadata = None
+
+    if schema is not None:
+        to_remove = schema.get_field_index("extra")
+        if to_remove >= 0:
+            expected_schema = schema.remove(to_remove)
+        else:
+            expected_schema = schema
+    else:
+        expected_schema = pa.schema(
+            {
+                "id": pa.int64(),
+                "text": pa.large_utf8()
+                if isinstance(data, pl.DataFrame)
+                else pa.string(),
+                "vector": pa.list_(pa.float32(), 10),
+            }
+        )
+
+    if not with_embedding:
+        to_remove = expected_schema.get_field_index("vector")
+        if to_remove >= 0:
+            expected_schema = expected_schema.remove(to_remove)
+
+    expected = pa.table(
+        {
+            "id": [1],
+            "text": ["hello"],
+            "vector": [[0.0] * 10],
+        },
+        schema=expected_schema,
+    )
+
+    output_data = _sanitize_data(
+        data,
+        target_schema=schema,
+        metadata=metadata,
+        allow_subschema=True,
+    )
+
+    assert output_data == expected
+
+
+def test_cast_to_target_schema():
+    original_schema = pa.schema(
+        {
+            "id": pa.int32(),
+            "struct": pa.struct(
+                [
+                    pa.field("a", pa.int32()),
+                ]
+            ),
+            "vector": pa.list_(pa.float64()),
+            "vec1": pa.list_(pa.float64(), 2),
+            "vec2": pa.list_(pa.float32(), 2),
+        }
+    )
+    data = pa.table(
+        {
+            "id": [1],
+            "struct": [{"a": 1}],
+            "vector": [[0.0] * 2],
+            "vec1": [[0.0] * 2],
+            "vec2": [[0.0] * 2],
+        },
+        schema=original_schema,
+    )
+
+    target = pa.schema(
+        {
+            "id": pa.int64(),
+            "struct": pa.struct(
+                [
+                    pa.field("a", pa.int64()),
+                ]
+            ),
+            "vector": pa.list_(pa.float32(), 2),
+            "vec1": pa.list_(pa.float32(), 2),
+            "vec2": pa.list_(pa.float32(), 2),
+        }
+    )
+    output = _cast_to_target_schema(data, target)
+    expected = pa.table(
+        {
+            "id": [1],
+            "struct": [{"a": 1}],
+            "vector": [[0.0] * 2],
+            "vec1": [[0.0] * 2],
+            "vec2": [[0.0] * 2],
+        },
+        schema=target,
+    )
+
+    # Data can be a subschema of the target
+    target = pa.schema(
+        {
+            "id": pa.int64(),
+            "struct": pa.struct(
+                [
+                    pa.field("a", pa.int64()),
+                    # Additional nested field
+                    pa.field("b", pa.int64()),
+                ]
+            ),
+            "vector": pa.list_(pa.float32(), 2),
+            "vec1": pa.list_(pa.float32(), 2),
+            "vec2": pa.list_(pa.float32(), 2),
+            # Additional field
+            "extra": pa.int64(),
+        }
+    )
+    with pytest.raises(Exception):
+        _cast_to_target_schema(data, target)
+    output = _cast_to_target_schema(data, target, allow_subschema=True)
+    expected_schema = pa.schema(
+        {
+            "id": pa.int64(),
+            "struct": pa.struct(
+                [
+                    pa.field("a", pa.int64()),
+                ]
+            ),
+            "vector": pa.list_(pa.float32(), 2),
+            "vec1": pa.list_(pa.float32(), 2),
+            "vec2": pa.list_(pa.float32(), 2),
+        }
+    )
+    expected = pa.table(
+        {
+            "id": [1],
+            "struct": [{"a": 1}],
+            "vector": [[0.0] * 2],
+            "vec1": [[0.0] * 2],
+            "vec2": [[0.0] * 2],
+        },
+        schema=expected_schema,
+    )
+    assert output == expected