feat(python): add opt-in request batching to TypeSafeReranker (#4316)

Adds opt-in `batch_size=40`: 80 non-null candidates use **2 requests
instead of 80**. Default `batch_size=1` preserves the existing payload.
Each batched question sees only its document and the shared query;
instructions/criteria stay unchanged. Prompts referencing
`state.document` need adaptation. Concurrency still limits requests;
retries remain SDK-managed. Batch-local IDs and ordered results preserve
duplicate documents; invalid IDs/probabilities raise without fallback.

Validation: **124 automated tests passed**, plus live search
integrations in both modes. A **100-query live subset test of the
initial implementation** (6,851 candidate pairs; `jev-1.13.0`, SDK
0.7.1, concurrency 32) passed: unbatched/batched calls **6,851/199**,
median **877/351 ms**, p95 **9,446/598 ms**. Hybrid Hit@5/Hit@10 was
**83%/89% vs 84%/90%**; vector/FTS results and exact configuration are
in the [test
report](https://github.com/lancedb/lancedb/blob/typesafe-request-batching/python/benchmarks/typesafe_batching.md).
Ruff and MkDocs passed. The simplified batching flow also passed a fresh
four-query live check: 292 candidate pairs, with 292 unbatched versus 8
batched calls.

Builds on #4209; motivated by [research
#7](https://github.com/lancedb/research/pull/7).
This commit is contained in:
Taylor
2026-09-24 13:53:52 +05:30
committed by GitHub
parent b3f0e12e32
commit a6dcbba49e
8 changed files with 1070 additions and 26 deletions
+27 -12
View File
@@ -536,28 +536,43 @@ class _FakeTypeSafeClient:
def system_one(self, state, questions, model):
self.requests.append((state, questions, model))
query_words = set(state["query"].lower().split())
doc_words = set(state["document"].lower().split())
noul = len(query_words & doc_words) / len(query_words)
answers = {key: type("NoulAnswer", (), {"noul": noul})() for key in questions}
answers = {}
for key, question in questions.items():
document = (
state["document"]
if "document" in state
else question["instructions"]["document"]
)
doc_words = set(document.lower().split())
noul = len(query_words & doc_words) / len(query_words)
answers[key] = type("NoulAnswer", (), {"noul": noul})()
return type("SystemOneResponse", (), {"answers": answers})()
def test_typesafe_reranker_with_fake_client(tmp_path):
reranker = TypeSafeReranker(max_concurrency=4)
@pytest.mark.parametrize("batch_size", [1, 40])
@pytest.mark.parametrize("return_score", ["relevance", "all"])
def test_typesafe_reranker_with_fake_client(tmp_path, batch_size, return_score):
reranker = TypeSafeReranker(
max_concurrency=4, batch_size=batch_size, return_score=return_score
)
reranker._client = _FakeTypeSafeClient()
table, schema = get_test_table(tmp_path)
_run_test_reranker(reranker, table, "single player experience", None, schema)
state, questions, model = reranker._client.requests[0]
assert model == "jev-latest"
assert set(state) == {"query", "document"}
assert questions == {
"relevance": {
"type": "noul",
"instructions": reranker.instructions,
"criteria": reranker.criteria,
if batch_size == 1:
assert set(state) == {"query", "document"}
assert questions == {
"relevance": {
"type": "noul",
"instructions": reranker.instructions,
"criteria": reranker.criteria,
}
}
}
else:
assert set(state) == {"query"}
assert 1 <= len(questions) <= batch_size
def test_typesafe_reranker_scores_each_row():
@@ -0,0 +1,338 @@
# SPDX-License-Identifier: Apache-2.0
# SPDX-FileCopyrightText: Copyright The LanceDB Authors
import json
from threading import Barrier, Event, Lock
from types import SimpleNamespace
from unittest.mock import Mock
import lancedb
import pyarrow as pa
import pytest
from lancedb.index import FTS
from lancedb.rerankers import TypeSafeReranker
def response(questions, probability=0.5):
return SimpleNamespace(
answers={key: SimpleNamespace(noul=probability) for key in reversed(questions)}
)
def vector_results(documents):
return pa.table(
{
"text": pa.array(documents, type=pa.string()),
"_rowid": pa.array(range(len(documents)), type=pa.uint64()),
"_distance": pa.array(range(len(documents)), type=pa.float32()),
}
)
def fake_reranker(**kwargs):
reranker = TypeSafeReranker(**kwargs)
reranker._client = Mock()
reranker._client.system_one.side_effect = lambda **kw: response(kw["questions"])
return reranker
@pytest.mark.parametrize("batch_size", [0, -1, 1.5, 40.0, True, False, "40", None])
def test_invalid_batch_size(batch_size):
with pytest.raises(ValueError, match="batch_size must be a positive integer"):
TypeSafeReranker(batch_size=batch_size)
@pytest.mark.parametrize("batch_size", [1, 7, 40])
@pytest.mark.parametrize("count", [0, 1, 39, 40, 41, 80, 81])
def test_request_counts_and_boundaries(batch_size, count):
reranker = fake_reranker(batch_size=batch_size)
docs = [f"candidate {i}" for i in range(count)]
result = reranker.rerank_vector("query", vector_results(docs))
calls = reranker._client.system_one.call_args_list
assert len(calls) == (count + batch_size - 1) // batch_size
assert sorted(len(call.kwargs["questions"]) for call in calls) == sorted(
min(batch_size, count - start) for start in range(0, count, batch_size)
)
assert result["_rowid"].to_pylist() == list(range(count))
@pytest.mark.parametrize("batch_size", [1, 40])
@pytest.mark.parametrize(
"criteria", [{}, {"true": " state.document fits\nexactly", "false": "No!"}]
)
def test_payload_isolation_and_custom_prompts(batch_size, criteria):
instructions = "Read state.document and state.query.\n Preserve this text. "
reranker = fake_reranker(
batch_size=batch_size,
instructions=instructions,
criteria=criteria,
model_name="jev-1.13.0",
column="body",
)
docs = [f"UNIQUE_CANDIDATE_{i}" for i in range(41)]
table = vector_results(docs).rename_columns(["body", "_rowid", "_distance"])
reranker.rerank_vector("shared query", table)
seen = []
for call in reranker._client.system_one.call_args_list:
state, questions = call.kwargs["state"], call.kwargs["questions"]
assert call.kwargs["model"] == "jev-1.13.0"
if batch_size == 1:
doc = state["document"]
assert state == {"query": "shared query", "document": doc}
assert list(questions) == ["relevance"]
expected_instructions = instructions
else:
assert state == {"query": "shared query"}
for question in questions.values():
if batch_size > 1:
doc = question["instructions"]["document"]
expected_instructions = {"question": instructions, "document": doc}
expected = {"type": "noul", "instructions": expected_instructions}
if criteria:
expected["criteria"] = criteria
# Exact equality rules out other candidates anywhere in this question.
assert question == expected
seen.append(doc)
assert sorted(seen) == sorted(docs)
assert reranker.instructions == instructions
assert reranker.criteria == criteria
def test_default_payload():
reranker = fake_reranker()
reranker.rerank_vector("query", vector_results(["document"]))
reranker._client.system_one.assert_called_once_with(
state={"query": "query", "document": "document"},
questions={
"relevance": {
"type": "noul",
"instructions": reranker.instructions,
"criteria": reranker.criteria,
}
},
model="jev-latest",
)
def test_response_mapping_with_duplicates_and_nulls():
reranker = fake_reranker(batch_size=2, max_concurrency=2, return_score="all")
second_batch_scored = Event()
def score(**kw):
questions = kw["questions"]
documents = [
question["instructions"]["document"] for question in questions.values()
]
if documents == ["same", "same"]:
# Prepare the later batch first; result order must still match input.
assert second_batch_scored.wait(timeout=10)
scores = [0.0, 0.5]
else:
assert documents == ["different", "same"]
scores = [0.75, 1.0]
result = SimpleNamespace(
answers={
key: SimpleNamespace(noul=value)
for key, value in reversed(list(zip(questions, scores)))
}
)
second_batch_scored.set()
return result
reranker._client.system_one.side_effect = score
result = reranker.rerank_vector(
"query", vector_results(["same", None, "same", "different", "same"])
)
assert result["_rowid"].to_pylist() == [4, 3, 2, 0, 1]
assert result["_distance"].to_pylist() == [4, 3, 2, 0, 1]
assert result["_relevance_score"].to_pylist() == [1, 0.75, 0.5, 0, 0]
assert reranker._client.system_one.call_count == 2
@pytest.mark.parametrize("batch_size", [1, 40])
@pytest.mark.parametrize("problem", ["missing", "unexpected", "replaced", "no_noul"])
def test_invalid_answers(batch_size, problem):
reranker = fake_reranker(batch_size=batch_size)
def invalid(**kw):
result = response(kw["questions"])
key = next(iter(result.answers))
if problem in ("missing", "replaced"):
del result.answers[key]
if problem in ("unexpected", "replaced"):
result.answers["unknown"] = SimpleNamespace(noul=0.5)
if problem == "no_noul":
result.answers[key] = SimpleNamespace()
return result
reranker._client.system_one.side_effect = invalid
with pytest.raises(ValueError, match="invalid relevance|answer IDs"):
reranker.rerank_vector("query", vector_results(["one", "two"]))
@pytest.mark.parametrize("batch_size", [1, 40])
@pytest.mark.parametrize(
"probability",
[None, True, False, "0.5", -0.01, 1.01, float("nan"), float("inf"), -float("inf")],
)
def test_invalid_probabilities(batch_size, probability):
reranker = fake_reranker(batch_size=batch_size)
reranker._client.system_one.side_effect = lambda **kw: response(
kw["questions"], probability
)
with pytest.raises(ValueError, match="invalid relevance probability"):
reranker.rerank_vector("query", vector_results(["one", "two"]))
@pytest.mark.parametrize("batch_size", [1, 40])
def test_api_failure_propagates(batch_size):
reranker = fake_reranker(batch_size=batch_size)
error = RuntimeError("SDK exhausted retries")
reranker._client.system_one.side_effect = error
with pytest.raises(RuntimeError) as caught:
reranker.rerank_vector("query", vector_results(["one"]))
assert caught.value is error
assert reranker._client.system_one.call_count == 1
@pytest.mark.parametrize("batch_size", [1, 40])
def test_concurrency_limits_requests(batch_size):
reranker = fake_reranker(batch_size=batch_size, max_concurrency=2)
barrier, lock = Barrier(2), Lock()
active = peak = 0
def blocking(**kw):
nonlocal active, peak
with lock:
active += 1
peak = max(peak, active)
barrier.wait(timeout=10)
with lock:
active -= 1
return response(kw["questions"])
reranker._client.system_one.side_effect = blocking
reranker.rerank_vector("query", vector_results(["doc"] * (6 * batch_size)))
assert peak == 2
assert active == 0
assert reranker._client.system_one.call_count == 6
@pytest.mark.parametrize("batch_size", [1, 40])
@pytest.mark.parametrize("return_score", ["relevance", "all"])
@pytest.mark.parametrize("method", ["vector", "fts", "hybrid"])
@pytest.mark.parametrize("docs", [[], [None, None], [None, "", None]])
def test_empty_and_null_inputs(batch_size, return_score, method, docs):
reranker = fake_reranker(batch_size=batch_size, return_score=return_score)
vector = vector_results(docs)
fts = vector.rename_columns(["text", "_rowid", "_score"])
args = (
(vector, fts)
if method == "hybrid"
else (vector if method == "vector" else fts,)
)
result = getattr(reranker, f"rerank_{method}")("query", *args)
assert len(result) == len(docs)
assert result["_relevance_score"].type == pa.float32()
assert sorted(result["_relevance_score"].to_pylist()) == sorted(
0 if doc is None else 0.5 for doc in docs
)
assert reranker._client.system_one.call_count == docs.count("")
if return_score == "relevance":
assert "_distance" not in result.column_names
assert "_score" not in result.column_names
@pytest.mark.parametrize("batch_size", [1, 40])
@pytest.mark.parametrize("return_score", ["relevance", "all"])
def test_hybrid_deduplicates_by_row_id_and_keeps_scores(batch_size, return_score):
reranker = fake_reranker(batch_size=batch_size, return_score=return_score)
vector = vector_results(["same", "same", "third"])
fts = vector.slice(1).rename_columns(["text", "_rowid", "_score"])
result = reranker.rerank_hybrid("query", vector.slice(0, 2), fts)
assert result["_rowid"].to_pylist() == [0, 1, 2]
assert (
sum(
len(call.kwargs["questions"])
for call in reranker._client.system_one.call_args_list
)
== 3
)
assert reranker._client.system_one.call_count == (3 if batch_size == 1 else 1)
if return_score == "all":
assert result["_distance"].to_pylist() == [0, 1, None]
assert result["_score"].to_pylist() == [None, 1, 2]
else:
assert result.column_names == ["text", "_rowid", "_relevance_score"]
@pytest.mark.asyncio
@pytest.mark.parametrize("batch_size", [1, 40])
async def test_async_search_integrations(tmp_path, batch_size):
db = await lancedb.connect_async(tmp_path)
table = await db.create_table(
"docs",
[
{"text": "cat naps", "vector": [1.0, 0.0]},
{"text": "cat plays", "vector": [0.0, 1.0]},
],
)
await table.create_index("text", config=FTS())
reranker = fake_reranker(batch_size=batch_size)
queries = [
table.query().nearest_to([1.0, 0.0]).rerank(reranker, query_string="cat"),
table.query().nearest_to_text("cat").rerank(reranker),
table.query().nearest_to([1.0, 0.0]).nearest_to_text("cat").rerank(reranker),
]
for query in queries:
reranker._client.system_one.reset_mock()
result = await query.with_row_id().to_arrow()
assert sorted(result["_rowid"].to_pylist()) == [0, 1]
assert result["_relevance_score"].to_pylist() == [0.5, 0.5]
assert "_distance" not in result.column_names
assert "_score" not in result.column_names
assert reranker._client.system_one.call_count == (2 if batch_size == 1 else 1)
@pytest.mark.parametrize("batch_size", [1, 40])
@pytest.mark.parametrize("retry_once", [False, True])
def test_sdk_transport_and_retries(batch_size, retry_once):
sdk = pytest.importorskip("typesafe_sdk")
httpx = pytest.importorskip("httpx2")
payloads = []
def handle(request):
payload = json.loads(request.content)
payloads.append(payload)
if retry_once and len(payloads) == 1:
return httpx.Response(503, headers={"retry-after-ms": "0"})
return httpx.Response(
200,
json={
"model": "jev-1.13.0",
"usage": {},
"answers": {
key: {"type": "noul", "noul": 0.5}
for key in reversed(payload["questions"])
},
},
)
with sdk.TypeSafeClient(
api_key="test-key", transport=httpx.MockTransport(handle)
) as client:
reranker = TypeSafeReranker(batch_size=batch_size, max_concurrency=1)
reranker._client = client
result = reranker.rerank_vector("query", vector_results(["document"] * 80))
assert len(payloads) == (80 if batch_size == 1 else 2) + int(retry_once)
assert result["_relevance_score"].to_pylist() == [0.5] * 80
if retry_once:
assert payloads[0] == payloads[1]
for payload in payloads:
assert len(payload["questions"]) == batch_size
if batch_size == 40:
assert payload["state"] == {"query": "query"}
assert all(
question["instructions"]["document"] == "document"
for question in payload["questions"].values()
)