Files
lancedb/python/python/tests/test_materialized_views.py
T
Jack Ye 7e8f0d4982 refactor: always fully refresh materialized views (#4373)
Simplify experimental materialized views to one output-only storage
layout and one full-rebuild refresh implementation.

## Current layout

Local materialized views currently maintain incremental-refresh state
alongside the materialized values:

- an internal `__source_row_id` column for source provenance;
- `mv.definition` plus `mv.incarnation`;
- source version/timestamp, view version, and last-refresh watermarks;
- optional `mv.staging` state for table-function sources; and
- stable-row-ID requirements on the source table.

Refresh classifies source changes, appends or evicts rows when possible,
and falls back to a rebuild for unsupported deltas. Remote
create/refresh also use separate REST mutation paths.

## New layout

An MV is an ordinary Lance backing table containing only:

- the defining query's output columns;
- its current data fragments; and
- `mv.definition`, encoded as a versioned SQL envelope such as
`{"kind":"query","format":1,"query":"SELECT ..."}`.

There is no provenance column, incarnation, source/view watermark,
staging metadata, or stable-row-ID requirement. Local refresh may still
pin a source version for reproducibility, but it always recomputes the
complete result.

Full refresh streams the new result into uncommitted fragments and then
publishes a single transaction that removes every old fragment and
installs the new set. A shared conflict token prevents concurrent
replacements from both committing. This fragment-replacement primitive
is also used by Sophon's SQL worker.

## New remote create workflow

```text
Connection::create_materialized_view(...)
        -> builder renders the defining SELECT
        -> remote Database receives a CreateMaterializedViewRequest
        -> submit CREATE MATERIALIZED VIEW ... AS ... through Flight SQL
        -> retain the SQL Query handle while the Job is running
        -> consume the durable SQL-job result
        -> open the created table and read mv.definition
        -> return MaterializedView
```

Remote refresh similarly submits `REFRESH MATERIALIZED VIEW` through
Flight SQL. Cancelling either wrapper forwards cancellation to the
retained SQL query before aborting the local task, so the server
operation is not silently left running.

## API changes

- remove incremental/no-op modes and the `full` switch;
- remove distributed grouped/partitioned refresh APIs and native
vector-source MV APIs;
- keep full-refresh results across Rust, Python, and TypeScript;
- preserve list/describe/drop as object-management operations while
routing create/refresh mutations through SQL.

The storage contract is experimental and has no compatibility shim;
views using the removed layout must be recreated.
2026-10-05 21:33:34 -07:00

512 lines
17 KiB
Python

# SPDX-License-Identifier: Apache-2.0
# SPDX-FileCopyrightText: Copyright The LanceDB Authors
import contextlib
import http.server
import json
import threading
import lancedb
import pytest
from lancedb.materialized_view import MaterializedViewDefinition
from lancedb.remote.db import RemoteDBConnection
STABLE_ROW_IDS = {"new_table_enable_stable_row_ids": "true"}
def make_db(tmp_path):
db = lancedb.connect(tmp_path, storage_options=STABLE_ROW_IDS)
db.create_table(
"people",
[
{"name": "ada", "age": 36},
{"name": "kid", "age": 7},
{"name": "grace", "age": 85},
],
)
return db
@contextlib.contextmanager
def mock_remote_materialized_views():
requests = []
class Handler(http.server.BaseHTTPRequestHandler):
def log_message(self, *args):
pass
def do_GET(self):
requests.append(self.path)
encoded = json.dumps({"views": ["daily_sales"]}).encode()
self.send_response(200)
self.send_header("Content-Type", "application/json")
self.send_header("Content-Length", str(len(encoded)))
self.end_headers()
self.wfile.write(encoded)
with http.server.HTTPServer(("localhost", 0), Handler) as server:
thread = threading.Thread(target=server.serve_forever)
thread.start()
try:
yield f"http://localhost:{server.server_address[1]}", requests
finally:
server.shutdown()
thread.join()
@contextlib.contextmanager
def mock_remote_materialized_view_create():
requests = []
class Handler(http.server.BaseHTTPRequestHandler):
def log_message(self, *args):
pass
def do_POST(self):
length = int(self.headers.get("Content-Length", 0))
body = json.loads(self.rfile.read(length) or b"{}")
requests.append((self.path, body))
job_id = "mv-drop-123" if self.path.endswith("/drop") else "mv-create-123"
encoded = json.dumps({"job_id": job_id}).encode()
self.send_response(202)
self.send_header("Content-Type", "application/json")
self.send_header("Content-Length", str(len(encoded)))
self.end_headers()
self.wfile.write(encoded)
with http.server.HTTPServer(("localhost", 0), Handler) as server:
thread = threading.Thread(target=server.serve_forever)
thread.start()
try:
yield f"http://localhost:{server.server_address[1]}", requests
finally:
server.shutdown()
thread.join()
def test_remote_list_uses_namespace_route():
with mock_remote_materialized_views() as (host, requests):
db = lancedb.connect(
"db://dev",
api_key="fake",
host_override=host,
client_config={"retry_config": {"retries": 0}},
)
assert db.list_materialized_views() == ["daily_sales"]
assert requests == ["/v1/namespace/$/materialized_view/list"]
def test_remote_drop_async_returns_server_job():
with mock_remote_materialized_view_create() as (host, requests):
db = lancedb.connect(
"db://dev",
api_key="fake",
host_override=host,
client_config={"retry_config": {"retries": 0}},
)
job = db.drop_materialized_view_async("adults")
assert job.id == "mv-drop-123"
assert requests == [("/v1/materialized_view/adults/drop", {})]
def test_sync_remote_create_uses_public_async_connection():
calls = []
class StubAsyncTable:
name = "adults"
class StubAsyncMaterializedView:
table = StubAsyncTable()
class StrictAsyncConnection:
async def create_materialized_view(
self,
name,
source,
*,
select=None,
where=None,
limit=None,
with_no_data=False,
):
calls.append((name, source, select, where, limit, with_no_data))
return StubAsyncMaterializedView()
async def drop_materialized_view(self, name, *, namespace_path=None):
calls.append(("drop", name, namespace_path))
db = RemoteDBConnection.__new__(RemoteDBConnection)
db._conn = StrictAsyncConnection()
db.db_name = "example"
db.serialize = lambda: "{}"
view = db.create_materialized_view(
"adults",
"people",
select=["name"],
where="age >= 18",
limit=10,
with_no_data=True,
)
assert view.name == "adults"
assert calls == [("adults", "people", ["name"], "age >= 18", 10, True)]
db.drop_materialized_view("adults", namespace_path=["analytics"])
assert calls[-1] == ("drop", "adults", ["analytics"])
def test_create_refresh_and_query(tmp_path):
db = make_db(tmp_path)
view = db.create_materialized_view(
"adults",
"people",
select=["name", ("shout", "upper(name)")],
where="age >= 18",
)
assert view.name == "adults"
assert view.table.count_rows() == 2
rows = view.table.search().to_list()
assert sorted(row["shout"] for row in rows) == ["ADA", "GRACE"]
def test_create_and_refresh_jobs(tmp_path):
db = make_db(tmp_path)
create_job = db.create_materialized_view_async(
"adults", "people", where="age >= 18", with_no_data=True
)
assert create_job.id is None
assert create_job.wait() is None
view = db.open_materialized_view("adults")
refresh_job = view.refresh_async()
assert refresh_job.id is None
result = refresh_job.wait()
assert result.mode == "rebuild"
assert result.rows_written == 2
assert view.table.count_rows() == 2
drop_job = db.drop_materialized_view_async("adults")
assert drop_job.id is None
assert drop_job.wait() is None
assert "adults" not in db.list_materialized_views()
def test_definition_round_trips(tmp_path):
db = make_db(tmp_path)
db.create_materialized_view("adults", "people", where="age >= 18")
view = db.open_materialized_view("adults")
assert view.definition == MaterializedViewDefinition(
query="SELECT name, age FROM people WHERE age >= 18"
)
def test_full_refresh_after_append(tmp_path):
db = make_db(tmp_path)
view = db.create_materialized_view("copy", "people", with_no_data=True)
view.refresh()
db.open_table("people").add([{"name": "alan", "age": 41}])
result = view.refresh()
assert result.mode == "rebuild"
assert result.rows_written == 4
assert view.table.count_rows() == 4
assert view.refresh().mode == "rebuild"
def test_full_refresh_after_update(tmp_path):
db = make_db(tmp_path)
view = db.create_materialized_view("copy", "people", with_no_data=True)
view.refresh()
db.open_table("people").update(where="name = 'kid'", values={"age": 8})
result = view.refresh()
assert result.mode == "rebuild"
assert result.rows_written == 3
rows = view.table.search().to_list()
assert sorted(row["age"] for row in rows) == [8, 36, 85]
def test_legacy_storage_source_update_rebuilds(tmp_path):
db = lancedb.connect(
tmp_path,
storage_options={**STABLE_ROW_IDS, "new_table_data_storage_version": "legacy"},
)
db.create_table("people", [{"name": "ada", "age": 36}, {"name": "kid", "age": 7}])
view = db.create_materialized_view("copy", "people", with_no_data=True)
view.refresh()
db.open_table("people").update(where="name = 'kid'", values={"age": 8})
result = view.refresh()
assert result.mode == "rebuild"
rows = view.table.search().to_list()
assert sorted(row["age"] for row in rows) == [8, 36]
def test_list_and_not_a_view(tmp_path):
db = make_db(tmp_path)
db.create_materialized_view("adults", "people", where="age >= 18")
assert db.list_materialized_views() == ["adults"]
with pytest.raises(ValueError, match="not a materialized view"):
db.open_materialized_view("people")
with pytest.raises(ValueError, match="not a materialized view"):
db.drop_materialized_view("people")
db.drop_materialized_view("adults")
assert db.list_materialized_views() == []
def test_invalid_expression_fails_at_create(tmp_path):
db = make_db(tmp_path)
with pytest.raises(Exception, match="missing"):
db.create_materialized_view("bad", "people", select=[("x", "missing + 1")])
assert "bad" not in db.list_tables().tables
@pytest.mark.asyncio
async def test_async_create_refresh_and_open(tmp_path):
db = await lancedb.connect_async(tmp_path, storage_options=STABLE_ROW_IDS)
await db.create_table("people", [{"name": "ada", "age": 36}])
view = await db.create_materialized_view(
"shouts",
"people",
select=[("shout", "upper(name)")],
with_no_data=True,
)
result = await view.refresh()
assert result.mode == "rebuild"
assert result.rows_written == 1
reopened = await db.open_materialized_view("shouts")
definition = await reopened.definition()
assert definition.query == "SELECT upper(name) AS shout FROM people"
assert await db.list_materialized_views() == ["shouts"]
@pytest.mark.asyncio
async def test_async_create_and_refresh_jobs(tmp_path):
db = await lancedb.connect_async(tmp_path, storage_options=STABLE_ROW_IDS)
await db.create_table("people", [{"name": "ada", "age": 36}])
create_job = await db.create_materialized_view_async(
"adults", "people", with_no_data=True
)
assert create_job.id is None
assert await create_job.wait() is None
view = await db.open_materialized_view("adults")
refresh_job = await view.refresh_async()
assert refresh_job.id is None
result = await refresh_job.wait()
assert result.mode == "rebuild"
assert result.rows_written == 1
drop_job = await db.drop_materialized_view_async("adults")
assert drop_job.id is None
assert await drop_job.wait() is None
assert "adults" not in await db.list_materialized_views()
@pytest.mark.asyncio
async def test_async_refresh_rebuilds(tmp_path):
db = await lancedb.connect_async(tmp_path)
await db.create_table("people", [{"name": "ada", "age": 36}])
view = await db.create_materialized_view("copy", "people", with_no_data=True)
await view.refresh()
table = await db.open_table("people")
await table.add([{"name": "alan", "age": 41}])
result = await view.refresh()
assert result.mode == "rebuild"
assert result.rows_written == 2
def test_source_does_not_require_stable_row_ids(tmp_path):
db = lancedb.connect(tmp_path)
db.create_table("plain", [{"x": 1}])
view = db.create_materialized_view("v", "plain")
assert view.table.count_rows() == 1
def test_bare_select_names_are_quoted(tmp_path):
db = lancedb.connect(tmp_path, storage_options=STABLE_ROW_IDS)
db.create_table("odd_names", [{"order item": "widget", "select": 2}])
view = db.create_materialized_view(
"quoted",
"odd_names",
select=["order item", "select"],
with_no_data=True,
)
result = view.refresh()
assert result.rows_written == 1
rows = view.table.search().to_list()
assert rows[0]["order item"] == "widget"
assert rows[0]["select"] == 2
def test_scalar_select_is_one_column(tmp_path):
db = make_db(tmp_path)
view = db.create_materialized_view("just_name", "people", select="name")
view.refresh()
rows = view.table.search().to_list()
assert set(rows[0]) == {"name"}
assert sorted(row["name"] for row in rows) == ["ada", "grace", "kid"]
@pytest.mark.asyncio
async def test_async_scalar_select_is_one_column(tmp_path):
db = await lancedb.connect_async(tmp_path, storage_options=STABLE_ROW_IDS)
await db.create_table("people", [{"name": "ada", "age": 36}])
view = await db.create_materialized_view("just_name", "people", select="name")
await view.refresh()
rows = await view.table.query().to_list()
assert set(rows[0]) == {"name"}
def test_limit_above_i64_max_is_refused(tmp_path):
db = make_db(tmp_path)
with pytest.raises(ValueError, match="exceeds the maximum"):
db.create_materialized_view("too_big", "people", limit=2**63)
# The boundary is fine, and zero still means an empty view.
db.create_materialized_view("at_max", "people", limit=2**63 - 1)
empty = db.create_materialized_view("none", "people", limit=0)
empty.refresh()
assert empty.table.count_rows() == 0
def _namespace_db(tmp_path):
return lancedb.connect_namespace(
"dir",
{"root": str(tmp_path)},
storage_options=STABLE_ROW_IDS,
)
def test_namespace_connection_materialized_views(tmp_path):
db = _namespace_db(tmp_path)
db.create_table(
"people",
[{"name": "ada", "age": 36}, {"name": "kid", "age": 7}],
storage_options=STABLE_ROW_IDS,
)
view = db.create_materialized_view("adults", "people", where="age >= 18")
view.refresh()
assert view.table.count_rows() == 1
assert db.list_materialized_views() == ["adults"]
reopened = db.open_materialized_view("adults")
assert reopened.definition.query.startswith("SELECT name, age FROM ")
with pytest.raises(ValueError, match="not a materialized view"):
db.open_materialized_view("people")
create_job = db.create_materialized_view_async(
"job_view", "people", with_no_data=True
)
assert create_job.wait() is None
refresh_job = db.open_materialized_view("job_view").refresh_async()
assert refresh_job.wait().rows_written == 2
assert db.drop_materialized_view_async("job_view").wait() is None
db.drop_materialized_view("adults")
assert db.list_materialized_views() == []
@pytest.mark.asyncio
async def test_async_namespace_connection_materialized_views(tmp_path):
db = lancedb.connect_namespace_async(
"dir",
{"root": str(tmp_path)},
storage_options=STABLE_ROW_IDS,
)
await db.create_table(
"people",
[{"name": "ada", "age": 36}, {"name": "kid", "age": 7}],
storage_options=STABLE_ROW_IDS,
)
view = await db.create_materialized_view("adults", "people", where="age >= 18")
await view.refresh()
assert await view.table.count_rows() == 1
assert await db.list_materialized_views() == ["adults"]
reopened = await db.open_materialized_view("adults")
assert (await reopened.definition()).query.startswith("SELECT name, age FROM ")
# The view's table came through the namespace, not straight from the
# inner connection: a bare inner table carries no namespace context, so
# its pushdown routing differs from a table the namespace opened.
through_namespace = await db.open_table("adults")
for handle in (view.table, reopened.table):
assert (
handle._route_pushdown_to_rust == through_namespace._route_pushdown_to_rust
)
assert handle._namespace_path == through_namespace._namespace_path
create_job = await db.create_materialized_view_async(
"job_view", "people", with_no_data=True
)
assert await create_job.wait() is None
job_view = await db.open_materialized_view("job_view")
refresh_job = await job_view.refresh_async()
assert (await refresh_job.wait()).rows_written == 2
drop_job = await db.drop_materialized_view_async("job_view")
assert await drop_job.wait() is None
await db.drop_materialized_view("adults")
assert await db.list_materialized_views() == []
def test_stored_queries_and_legacy_layouts_are_read():
import json
import pyarrow as pa
from lancedb.materialized_view import _definition_from_schema
def read(definition: dict) -> MaterializedViewDefinition:
schema = pa.schema([pa.field("id", pa.int32())]).with_metadata(
{b"mv.definition": json.dumps(definition).encode()}
)
return _definition_from_schema(schema, "v")
query = "SELECT id, c.chunk FROM ns.docs, UNNEST(chunks) AS c WHERE id > 1"
assert read({"format": 1, "query": query}).query == query
# The structured layout written before the format number reads as the
# query it described, under either of its kind tags.
assert (
read(
{
"kind": "namespaced_select",
"source_table": "people",
"source_namespace": ["ns"],
"projections": [
{"output": "name", "expression": "`name`"},
{"output": "Shout", "expression": "upper(name)"},
],
"filter": "age >= 18",
"limit": 10,
}
).query
== "SELECT `name`, upper(name) AS `Shout` FROM ns.people "
"WHERE age >= 18 LIMIT 10"
)
assert read({"kind": "select", "source_table": "people"}).query == (
"SELECT * FROM people"
)
# A newer writer's layout is reported, never guessed at.
for newer in (
{"format": 3, "query": query},
{"kind": "select_v3", "source_table": "people"},
):
with pytest.raises(NotImplementedError, match="cannot refresh"):
read(newer)