feat: expose list-element FTS document granularity (#4050)

## Summary

LanceDB could not request Lance's list-element FTS document granularity
through Python or Remote APIs, and generic nested-field resolution
exposed Arrow's internal `item` segment instead of the public field
path.

This exposes typed `row | list_element` configuration for Python FTS
index creation and match/phrase queries, preserves `_doc_index`, and
keeps nested FTS paths public (for example, `docs.content`). Remote
list-element requests require server API version 0.6.0 so older servers
cannot silently execute them with row semantics; explicit row requests
remain compatible.

## Compatibility

Omitted index and query parameters retain row granularity. Remote row
index creation omits the new wire field.

## Tracking


[ENT-2342](https://linear.app/lancedb/issue/ENT-2342/expose-list-element-fts-document-granularity-end-to-end)
This commit is contained in:
Xuanwo
2026-08-26 23:27:39 +08:00
committed by GitHub
parent 06872463cf
commit b78f2a5044
15 changed files with 723 additions and 55 deletions
+12
View File
@@ -7,6 +7,7 @@ from typing import List, Literal, Optional
from ._lancedb import (
IndexConfig,
)
from .query import DocumentGranularity
from .types import BaseTokenizerType
lang_mapping = {
@@ -121,6 +122,11 @@ class FTS:
>>> config = FTS(block_size=256)
Create an index that treats each deepest-list element as one document:
>>> from lancedb.query import DocumentGranularity
>>> config = FTS(document_granularity=DocumentGranularity.LIST_ELEMENT)
Attributes
----------
with_position : bool, default False
@@ -172,6 +178,11 @@ class FTS:
roughly half of the available CPU cores. The effective value is
limited by the available compute capacity. This build-only setting is
not persisted with the index and does not apply to remote tables.
document_granularity : DocumentGranularity, default ROW
``ROW`` treats the selected text in one table row as one document.
``LIST_ELEMENT`` treats each element of the deepest list on the indexed
field path as one document and returns its physical coordinates in
``_doc_index`` for matching queries.
Notes
-----
@@ -196,6 +207,7 @@ class FTS:
custom_stop_words: Optional[List[str]] = None
memory_limit: Optional[int] = None
num_workers: Optional[int] = None
document_granularity: DocumentGranularity = DocumentGranularity.ROW
@dataclass
+23
View File
@@ -375,6 +375,13 @@ class FullTextOperator(str, Enum):
OR = "OR"
class DocumentGranularity(str, Enum):
"""The unit treated as one full-text-search document."""
ROW = "row"
LIST_ELEMENT = "list_element"
class Occur(str, Enum):
SHOULD = "SHOULD"
MUST = "MUST"
@@ -478,6 +485,10 @@ class MatchQuery(FullTextQuery):
prefix_length : int, optional
The number of beginning characters being unchanged for fuzzy matching.
This is useful to achieve prefix matching.
document_granularity : DocumentGranularity, optional
Explicitly select row or deepest-list-element documents. If omitted,
the indexed granularity is inferred. When both granularities are indexed
for the field, this must be specified. With no index, row granularity is used.
"""
query: str
@@ -487,6 +498,9 @@ class MatchQuery(FullTextQuery):
max_expansions: int = pydantic.Field(50, kw_only=True)
operator: FullTextOperator = pydantic.Field(FullTextOperator.OR, kw_only=True)
prefix_length: int = pydantic.Field(0, kw_only=True)
document_granularity: Optional[DocumentGranularity] = pydantic.Field(
None, kw_only=True
)
def query_type(self) -> FullTextQueryType:
return FullTextQueryType.MATCH
@@ -503,11 +517,20 @@ class PhraseQuery(FullTextQuery):
The query string to match against.
column : str
The name of the column to match against.
slop : int, default 0
The maximum number of intervening positions permitted in the phrase.
document_granularity : DocumentGranularity, optional
Explicitly select row or deepest-list-element documents. If omitted,
the indexed granularity is inferred. When both granularities are indexed
for the field, this must be specified. With no index, row granularity is used.
"""
query: str
column: str
slop: int = pydantic.Field(0, kw_only=True)
document_granularity: Optional[DocumentGranularity] = pydantic.Field(
None, kw_only=True
)
def query_type(self) -> FullTextQueryType:
return FullTextQueryType.MATCH_PHRASE
+3
View File
@@ -61,6 +61,7 @@ from lancedb.table import _normalize_progress
from ..query import (
AnalyzePlanDistributedMetrics,
DocumentGranularity,
LanceQueryBuilder,
LanceTakeQueryBuilder,
LanceVectorQueryBuilder,
@@ -349,6 +350,7 @@ class RemoteTable(Table):
ngram_max_length: int = 3,
prefix_only: bool = False,
block_size: int = 128,
document_granularity: DocumentGranularity = DocumentGranularity.ROW,
name: Optional[str] = None,
):
"""Create a full-text search index on a column.
@@ -371,6 +373,7 @@ class RemoteTable(Table):
ngram_max_length=ngram_max_length,
prefix_only=prefix_only,
block_size=block_size,
document_granularity=document_granularity,
)
LOOP.run(
self._table.create_index(
+13 -1
View File
@@ -85,6 +85,7 @@ from .query import (
AsyncQuery,
AsyncTakeQuery,
AsyncVectorQuery,
DocumentGranularity,
FullTextQuery,
LanceEmptyQueryBuilder,
LanceFtsQueryBuilder,
@@ -1168,6 +1169,7 @@ class Table(ABC):
ngram_max_length: int = 3,
prefix_only: bool = False,
block_size: int = 128,
document_granularity: DocumentGranularity = DocumentGranularity.ROW,
wait_timeout: Optional[timedelta] = None,
name: Optional[str] = None,
):
@@ -1246,6 +1248,11 @@ class Table(ABC):
The number of documents per compressed posting block. Must be 128
or 256. A value of 256 uses the experimental FTS V3 format and
may introduce breaking changes.
document_granularity: DocumentGranularity, default ROW
``ROW`` treats the selected text in one table row as one document.
``LIST_ELEMENT`` treats each element of the deepest list on the field
path as one document and returns its physical coordinates in
``_doc_index`` for matching queries.
wait_timeout: timedelta, optional
The timeout to wait if indexing is asynchronous.
name: str, optional
@@ -3273,6 +3280,7 @@ class LanceTable(Table):
ngram_max_length: int = 3,
prefix_only: bool = False,
block_size: int = 128,
document_granularity: DocumentGranularity = DocumentGranularity.ROW,
name: Optional[str] = None,
):
"""Create a full-text search index on a column.
@@ -3324,7 +3332,11 @@ class LanceTable(Table):
tokenizer_configs = self.infer_tokenizer_configs(tokenizer_name)
tokenizer_configs["custom_stop_words"] = custom_stop_words
config = FTS(block_size=block_size, **tokenizer_configs)
config = FTS(
block_size=block_size,
document_granularity=document_granularity,
**tokenizer_configs,
)
try:
LOOP.run(
+77
View File
@@ -25,6 +25,7 @@ from lancedb.db import DBConnection
from lancedb.index import FTS
from lancedb.query import (
BoostQuery,
DocumentGranularity,
MatchQuery,
MultiMatchQuery,
PhraseQuery,
@@ -245,6 +246,55 @@ def test_create_inverted_index_rejects_invalid_block_size(table):
table.create_index("text", config=FTS(block_size=129))
def test_list_element_document_granularity(tmp_path):
docs_type = pa.list_(pa.struct([pa.field("content", pa.string())]))
docs = pa.array(
[
[
{"content": "alpha beta"},
None,
{"content": ""},
{"content": "the and"},
{"content": "alpha beta"},
]
],
type=docs_type,
)
table = ldb.connect(tmp_path).create_table(
"list_element_docs", pa.table({"id": [0], "docs": docs})
)
row_table = ldb.connect(tmp_path).create_table(
"row_docs", pa.table({"id": [0], "docs": docs})
)
row_table.create_index("docs.content", config=FTS())
row_result = row_table.search(MatchQuery("alpha", "docs.content")).to_arrow()
assert row_result.num_rows == 1
assert "_doc_index" not in row_result.column_names
granularity = DocumentGranularity.LIST_ELEMENT
table.create_index(
"docs.content",
config=FTS(with_position=True, document_granularity=granularity),
)
assert table.list_indices()[0].columns == ["docs.content"]
def coordinates(query):
result = table.search(query).limit(10).to_arrow()
doc_index_type = result.schema.field("_doc_index").type
assert pa.types.is_list(doc_index_type)
assert doc_index_type.value_type == pa.uint32()
return sorted(result["_doc_index"].to_pylist())
assert coordinates(
MatchQuery("alpha", "docs.content", document_granularity=granularity)
) == [[0], [4]]
assert coordinates(
PhraseQuery("alpha beta", "docs.content", document_granularity=granularity)
) == [[0], [4]]
assert coordinates(MatchQuery("alpha", "docs.content")) == [[0], [4]]
assert FTS().document_granularity is DocumentGranularity.ROW
def test_create_inverted_index_respects_build_memory_limit(table):
with pytest.raises(ValueError, match="exceeds worker memory limit"):
table.create_index(
@@ -1089,6 +1139,20 @@ def test_fts_query_to_json():
)
assert json_str == expected
# Test MatchQuery with list-element document granularity
match_query = MatchQuery(
"hello world",
"text",
document_granularity=DocumentGranularity.LIST_ELEMENT,
)
json_str = match_query.to_json()
expected = (
'{"match":{"column":"text","terms":"hello world","boost":1.0,'
'"fuzziness":0,"max_expansions":50,"operator":"Or","prefix_length":0,'
'"document_granularity":"list_element"}}'
)
assert json_str == expected
# Test MatchQuery with options
match_query = MatchQuery("puppy", "text", fuzziness=2, boost=1.5, prefix_length=3)
json_str = match_query.to_json()
@@ -1098,6 +1162,19 @@ def test_fts_query_to_json():
)
assert json_str == expected
# Test PhraseQuery with list-element document granularity
phrase_query = PhraseQuery(
"quick brown fox",
"title",
document_granularity=DocumentGranularity.LIST_ELEMENT,
)
json_str = phrase_query.to_json()
expected = (
'{"phrase":{"column":"title","terms":"quick brown fox","slop":0,'
'"document_granularity":"list_element"}}'
)
assert json_str == expected
# Test PhraseQuery
phrase_query = PhraseQuery("quick brown fox", "title")
json_str = phrase_query.to_json()
+43
View File
@@ -1618,6 +1618,49 @@ def test_query_sync_fts():
)
def test_query_sync_fts_document_granularity():
from lancedb.query import DocumentGranularity, MatchQuery
def handler(body):
assert body == {
"full_text_query": {
"query": {
"match": {
"column": "docs.content",
"terms": "alpha",
"boost": 1.0,
"fuzziness": 0,
"max_expansions": 50,
"operator": "Or",
"prefix_length": 0,
"document_granularity": "list_element",
}
}
},
"k": 10,
"prefilter": True,
"vector": [],
"version": None,
}
return pa.table(
{
"id": [1, 1],
"_doc_index": pa.array([[0], [4]], type=pa.list_(pa.uint32())),
}
)
with query_test_table(handler, server_version=Version("0.6.0")) as table:
result = table.search(
MatchQuery(
"alpha",
"docs.content",
document_granularity=DocumentGranularity.LIST_ELEMENT,
)
).to_arrow()
assert result["_doc_index"].to_pylist() == [[0], [4]]
def test_query_sync_hybrid():
def handler(body):
if "full_text_query" in body:
+8 -2
View File
@@ -8,7 +8,7 @@ use lancedb::index::vector::{
};
use lancedb::index::{
Index as LanceDbIndex,
scalar::{BTreeIndexBuilder, FmIndexBuilder, FtsIndexBuilder},
scalar::{BTreeIndexBuilder, DocumentGranularity, FmIndexBuilder, FtsIndexBuilder},
};
use pyo3::IntoPyObject;
use pyo3::types::PyStringMethods;
@@ -60,7 +60,11 @@ pub fn extract_index_params(source: &Option<Bound<'_, PyAny>>) -> PyResult<Lance
.ngram_min_length(params.ngram_min_length)
.ngram_max_length(params.ngram_max_length)
.ngram_prefix_only(params.prefix_only)
.custom_stop_words(params.custom_stop_words);
.custom_stop_words(params.custom_stop_words)
.document_granularity(
DocumentGranularity::try_from(params.document_granularity.as_str())
.map_err(|err| PyValueError::new_err(err.to_string()))?,
);
if let Some(memory_limit) = params.memory_limit {
inner_opts = inner_opts.memory_limit_mb(memory_limit);
}
@@ -221,6 +225,7 @@ struct FtsParams {
block_size: usize,
memory_limit: Option<u64>,
num_workers: Option<usize>,
document_granularity: String,
}
#[derive(FromPyObject)]
@@ -481,6 +486,7 @@ mod tests {
block_size = 128
memory_limit = 2048
num_workers = 7
document_granularity = 'row'
config = FTS()",
None,
+45 -12
View File
@@ -16,8 +16,8 @@ use arrow::pyarrow::FromPyArrow;
use arrow::pyarrow::IntoPyArrow;
use arrow::pyarrow::ToPyArrow;
use lancedb::index::scalar::{
BooleanQuery, BoostQuery, FtsQuery, FullTextSearchQuery, MatchQuery, MultiMatchQuery, Occur,
Operator, PhraseQuery,
BooleanQuery, BoostQuery, DocumentGranularity, FtsQuery, FullTextSearchQuery, MatchQuery,
MultiMatchQuery, Occur, Operator, PhraseQuery,
};
use lancedb::query::AnalyzePlanDistributedMetrics;
use lancedb::query::QueryBase;
@@ -76,8 +76,16 @@ impl<'a, 'py> FromPyObject<'a, 'py> for PyLanceDB<FtsQuery> {
let max_expansions = ob.getattr("max_expansions")?.extract()?;
let operator = ob.getattr("operator")?.extract::<String>()?;
let prefix_length = ob.getattr("prefix_length")?.extract()?;
let document_granularity = ob
.getattr("document_granularity")?
.extract::<Option<String>>()?
.map(|value| {
DocumentGranularity::try_from(value.as_str())
.map_err(|err| PyValueError::new_err(err.to_string()))
})
.transpose()?;
Ok(Self(
let mut query =
MatchQuery::new(query)
.with_column(Some(column))
.with_boost(boost)
@@ -86,21 +94,32 @@ impl<'a, 'py> FromPyObject<'a, 'py> for PyLanceDB<FtsQuery> {
.with_operator(Operator::try_from(operator.as_str()).map_err(|e| {
PyValueError::new_err(format!("Invalid operator: {}", e))
})?)
.with_prefix_length(prefix_length)
.into(),
))
.with_prefix_length(prefix_length);
if let Some(document_granularity) = document_granularity {
query = query.with_document_granularity(document_granularity);
}
Ok(Self(query.into()))
}
"PhraseQuery" => {
let query = ob.getattr("query")?.extract()?;
let column = ob.getattr("column")?.extract()?;
let slop = ob.getattr("slop")?.extract()?;
let document_granularity = ob
.getattr("document_granularity")?
.extract::<Option<String>>()?
.map(|value| {
DocumentGranularity::try_from(value.as_str())
.map_err(|err| PyValueError::new_err(err.to_string()))
})
.transpose()?;
Ok(Self(
PhraseQuery::new(query)
.with_column(Some(column))
.with_slop(slop)
.into(),
))
let mut query = PhraseQuery::new(query)
.with_column(Some(column))
.with_slop(slop);
if let Some(document_granularity) = document_granularity {
query = query.with_document_granularity(document_granularity);
}
Ok(Self(query.into()))
}
"BoostQuery" => {
let positive: Self = ob.getattr("positive")?.extract()?;
@@ -167,6 +186,13 @@ impl<'py> IntoPyObject<'py> for PyLanceDB<FtsQuery> {
kwargs.set_item("max_expansions", query.max_expansions)?;
kwargs.set_item::<_, &str>("operator", query.operator.into())?;
kwargs.set_item("prefix_length", query.prefix_length)?;
if let Some(document_granularity) = query.document_granularity {
let value = match document_granularity {
DocumentGranularity::Row => "row",
DocumentGranularity::ListElement => "list_element",
};
kwargs.set_item("document_granularity", value)?;
}
namespace
.getattr(intern!(py, "MatchQuery"))?
.call((query.terms, query.column.unwrap()), Some(&kwargs))
@@ -174,6 +200,13 @@ impl<'py> IntoPyObject<'py> for PyLanceDB<FtsQuery> {
FtsQuery::Phrase(query) => {
let kwargs = PyDict::new(py);
kwargs.set_item("slop", query.slop)?;
if let Some(document_granularity) = query.document_granularity {
let value = match document_granularity {
DocumentGranularity::Row => "row",
DocumentGranularity::ListElement => "list_element",
};
kwargs.set_item("document_granularity", value)?;
}
namespace
.getattr(intern!(py, "PhraseQuery"))?
.call((query.terms, query.column.unwrap()), Some(&kwargs))