Files
lancedb/nodejs/__test__/materialized_view.test.ts
T
Wyatt Alt f5e589bbe0 feat: define a materialized view by its query, with UNNEST for table-valued Functions
A view definition was a structured record under a `kind` tag, one kind
per query shape, and a Function returning `list<struct>` was about to
add a third. That names shapes instead of describing a relation.

A materialized view is now a relation defined by a query, stored as one
canonical SQL string under a format number:

    SELECT columns FROM [ns.]table [, UNNEST(column) AS alias]
      [WHERE predicate] [LIMIT n]

Any other clause is refused at parse time. Older readers report the view
as unrefreshable, the pre-format layouts still read, and a legacy view is
rewritten on its next refresh that commits, rebuilt only where its raw
text meant something else under lance's parser.

UNNEST is the first operator past project and filter: projections plan
against the source with the list column replaced by its element under
the alias, and refresh unnests, filters and projects each batch itself.
Row ids repeat per element, so eviction and incremental append are
unchanged. A limit is refused with UNNEST: a scan limit counts source rows.
2026-09-17 03:38:29 +00:00

183 lines
5.9 KiB
TypeScript

// SPDX-License-Identifier: Apache-2.0
// SPDX-FileCopyrightText: Copyright The LanceDB Authors
import * as tmp from "tmp";
import { Connection, connect } from "../lancedb";
import {
DEFINITION_META_KEY,
definitionFromMetadata,
} from "../lancedb/materialized_view";
describe("materialized views", () => {
let tmpDir: tmp.DirResult;
let db: Connection;
beforeEach(async () => {
tmpDir = tmp.dirSync({ unsafeCleanup: true });
db = await connect(tmpDir.name);
await db.createTable(
"people",
[
{ name: "ada", age: 36 },
{ name: "kid", age: 7 },
{ name: "grace", age: 85 },
],
{ storageOptions: { newTableEnableStableRowIds: "true" } },
);
});
afterEach(() => tmpDir.removeCallback());
it("reads stored queries and legacy layouts", () => {
const read = (stored: string) =>
definitionFromMetadata(new Map([[DEFINITION_META_KEY, stored]]), "v");
const query =
"SELECT id, c.chunk FROM ns.docs, UNNEST(chunks) AS c WHERE id > 1";
expect(read(`{"format":1,"query":${JSON.stringify(query)}}`).query).toBe(
query,
);
// The structured layout written before the format number reads as the
// query it described, under either of its kind tags.
expect(
read(
'{"kind":"namespaced_select","source_table":"people","source_namespace":["ns"],' +
'"projections":[{"output":"name","expression":"`name`"},' +
'{"output":"Shout","expression":"upper(name)"}],"filter":"age >= 18","limit":42}',
).query,
).toBe(
"SELECT `name`, upper(name) AS `Shout` FROM ns.people WHERE age >= 18 LIMIT 42",
);
expect(read('{"kind":"select","source_table":"people"}').query).toBe(
"SELECT * FROM people",
);
// A newer writer's layout is reported, never guessed at.
for (const newer of [
`{"format":2,"query":${JSON.stringify(query)}}`,
'{"kind":"select_v3","source_table":"people"}',
]) {
expect(() => read(newer)).toThrow(/cannot refresh/);
}
});
it("rejects a stored limit a number cannot carry", () => {
const big = new Map([
[
DEFINITION_META_KEY,
'{"kind":"select","source_table":"people","limit":9007199254740993}',
],
]);
expect(() => definitionFromMetadata(big, "v")).toThrow(
/too large to represent exactly/,
);
});
it("creates, refreshes and queries a view", async () => {
const view = await db.createMaterializedView("adults", "people", {
select: ["name", ["shout", "upper(name)"]],
where: "age >= 18",
});
expect(view.name).toBe("adults");
expect(await view.table().countRows()).toBe(2);
const rows = await view.table().query().toArray();
expect(rows.map((r) => r.shout).sort()).toEqual(["ADA", "GRACE"]);
});
it("round-trips the definition", async () => {
await db.createMaterializedView("adults", "people", {
where: "age >= 18",
});
const view = await db.openMaterializedView("adults");
const definition = await view.definition();
expect(definition.query).toBe(
"SELECT name, age FROM people WHERE age >= 18",
);
});
it("refreshes incrementally after an append", async () => {
const view = await db.createMaterializedView("copy", "people", {
withNoData: true,
});
await view.refresh();
const people = await db.openTable("people");
await people.add([{ name: "alan", age: 41 }]);
const result = await view.refresh();
expect(result.mode).toBe("incremental");
expect(Number(result.rowsWritten)).toBe(1);
expect(await view.table().countRows()).toBe(4);
expect((await view.refresh()).mode).toBe("no_op");
});
it("lists views and rejects non-views", async () => {
await db.createMaterializedView("adults", "people", {
where: "age >= 18",
});
expect(await db.listMaterializedViews()).toEqual(["adults"]);
await expect(db.openMaterializedView("people")).rejects.toThrow(
"not a materialized view",
);
await expect(db.dropMaterializedView("people")).rejects.toThrow(
"not a materialized view",
);
await db.dropMaterializedView("adults");
expect(await db.listMaterializedViews()).toEqual([]);
});
it("returns a job when dropping a view asynchronously", async () => {
await db.createMaterializedView("adults", "people");
const job = await db.dropMaterializedViewAsync("adults");
expect(job.id).toBeNull();
await job.wait();
expect(await db.listMaterializedViews()).toEqual([]);
});
it("rejects an invalid expression at create time", async () => {
await expect(
db.createMaterializedView("bad", "people", {
select: [["x", "missing + 1"]],
}),
).rejects.toThrow("missing");
});
it("rejects invalid numeric options before creating anything", async () => {
for (const limit of [-5, 1.5, Infinity, NaN]) {
await expect(
db.createMaterializedView("bad", "people", { limit }),
).rejects.toThrow("non-negative integer");
}
expect(await db.listMaterializedViews()).toEqual([]);
const view = await db.createMaterializedView("copy", "people");
for (const sourceVersion of [-1, 1.5, Infinity, NaN]) {
await expect(view.refresh({ sourceVersion })).rejects.toThrow(
"non-negative integer",
);
}
});
it("quotes bare select names", async () => {
await db.createTable("odd_names", [{ "order item": "widget" }], {
storageOptions: { newTableEnableStableRowIds: "true" },
});
const view = await db.createMaterializedView("quoted", "odd_names", {
select: ["order item"],
withNoData: true,
});
const result = await view.refresh();
expect(Number(result.rowsWritten)).toBe(1);
});
it("requires stable row ids on the source", async () => {
await db.createTable("plain", [{ x: 1 }]);
await expect(db.createMaterializedView("v", "plain")).rejects.toThrow(
"stable row ids",
);
});
});