Jack YeandXuanwo
6a07f88980
Add a `Catalog` trait and `RemoteCatalog` for managing databases,
exposed through Rust, synchronous/asynchronous Python, and TypeScript. A
remote catalog represents the server's root namespace, and each database
is one child namespace. Create/connect return ordinary LanceDB
connections, so existing table APIs work unchanged.
## Rust API
`Catalog` is an object-safe async trait with `create_database`,
`connect_database`, `list_databases`, and `drop_database`. Backend
create/connect methods return `Arc<dyn Database>`; the public
`CatalogConnection` wraps them as `Connection` values and shares its
embedding registry with those connections. `RemoteCatalog` implements
the trait; `connect_catalog` is the convenience builder, available with
the `remote` feature.
```rust
use lancedb::catalog::{
CreateDatabaseRequest, DropDatabaseRequest, ListDatabasesRequest,
};
let catalog = lancedb::connect_catalog("https://my-server.example")
.api_key("my-api-key")
.execute()
.await?;
let db = catalog.create_database(
CreateDatabaseRequest::new("analytics").exist_ok(true),
).await?;
let connected = catalog.connect_database("analytics").await?;
let page = catalog.list_databases(
ListDatabasesRequest::default().limit(20),
).await?;
// page.databases: Vec<String>; page.page_token: Option<String>
catalog.drop_database(
DropDatabaseRequest::new("analytics").ignore_missing(true),
).await?;
```
Create/drop also accept a plain name for default behavior, e.g.
`catalog.create_database("analytics").await?`. Existing names fail
creation unless `exist_ok` is enabled; missing names fail drop unless
`ignore_missing` is enabled. Drop always requires an empty database.
## Python API
```python
import lancedb
catalog = lancedb.connect_catalog(
"https://my-server.example", api_key="my-api-key"
)
db = catalog.create_database("analytics", exist_ok=True)
connected = catalog.connect_database("analytics")
page = catalog.list_databases(limit=20)
# page.databases: list[str]; page.page_token: Optional[str]
if page.page_token is not None:
next_page = catalog.list_databases(limit=20, page_token=page.page_token)
catalog.drop_database("analytics", ignore_missing=True)
```
`connect_catalog` returns `Catalog`; create/connect return the existing
`DBConnection` API. The async equivalent is `catalog = await
lancedb.connect_catalog_async(...)`, returning `AsyncCatalog`; await
each of the same four methods, with create/connect returning
`AsyncConnection`.
## TypeScript API
```typescript
import { connectCatalog } from "@lancedb/lancedb";
const catalog = await connectCatalog("https://my-server.example", {
apiKey: "my-api-key",
});
const db = await catalog.createDatabase("analytics", { existOk: true });
const connected = await catalog.connectDatabase("analytics");
const page = await catalog.listDatabases({ limit: 20 });
// page.databases: string[]; page.pageToken?: string
if (page.pageToken !== undefined) {
const nextPage = await catalog.listDatabases({
limit: 20, pageToken: page.pageToken,
});
}
await catalog.dropDatabase("analytics", { ignoreMissing: true });
```
Create/connect return the existing `Connection` API. All four methods
are asynchronous.
## REST mapping
All paths below are relative to the catalog endpoint. `{name}` is the
logical database name encoded as one URL path component. The default
namespace delimiter is `$`, so the root identifier is encoded as `%24`.
| Catalog operation | Existing REST route | Request |
| --- | --- | --- |
| `create_database(name)` | `POST /v1/namespace/{name}/create` |
`{"mode":"Create"}`; `exist_ok=true` sends `{"mode":"ExistOk"}` |
| `connect_database(name)` | `POST /v1/namespace/{name}/describe` |
`{}`; verifies existence before returning a scoped connection |
| `list_databases(...)` | `GET /v1/namespace/%24/list` | Optional
`limit` and `page_token` query parameters |
| `drop_database(name)` | `POST /v1/namespace/{name}/drop` |
`{"mode":"Fail","behavior":"Restrict"}`; `ignore_missing=true` changes
mode to `"Skip"` |
For example, database `team/search` uses
`/v1/namespace/team%2Fsearch/create`. A paginated root listing can use
`/v1/namespace/%24/list?limit=20&page_token=a%2Fb`. The list response
retains the existing namespace wire shape,
`{"namespaces":["analytics"],"page_token":"next"}`; the SDK exposes
`namespaces` as `databases` and preserves the opaque continuation token.
An absent or empty token ends pagination. Page limits must be between 1
and 2147483647. Create/drop accept a namespace JSON response or HTTP
204.
Catalog management requests omit both `x-lancedb-database` and
`x-lancedb-database-prefix`, including values supplied through static or
dynamic headers. Returned database connections set `x-lancedb-database`
to the exact logical name and keep independent scope. API keys, OAuth or
dynamic authentication, client settings, table read consistency
settings, and an optional SQL endpoint override carry over to those
connections. OAuth cannot be combined with an API key or a custom header
provider.
For SQL through an HTTPS catalog, configure the existing SQL endpoint
contract with Rust
`.sql_host_override("grpc+tls://sql.example.com:10026")` or Python
`sql_host_override="grpc+tls://sql.example.com:10026"`. TypeScript
catalog options expose the same setting as `sqlHostOverride`. It is
inherited by created/connected databases, retained by Python connection
serialization, and initialized lazily when SQL is executed.
Create HTTP 409 maps to `DatabaseAlreadyExists`; connect/drop HTTP 404
maps to `DatabaseNotFound`, except that `ignore_missing` suppresses a
missing-database drop. Other server errors propagate. The server
enforces restricted deletion; the client never requests cascading
deletion.
Database names preserve literal slashes as part of one name. They must
be nonempty ASCII, with no control characters, surrounding whitespace,
or configured namespace delimiter, and cannot be `.` or `..`. Endpoints
must be HTTP(S) URLs without embedded credentials, query parameters, or
fragments.
## Scope
This PR adds the client API and reuses existing namespace endpoints.
Local catalogs, `__catalog` storage, location generation/sanitization,
and `__manifest` lifecycle support remain deferred; the Lance dependency
is unchanged.
The PR also runs macOS Node tests serially to avoid existing
resource-contention timeouts reproduced across recent main runs.
---------
Co-authored-by: Xuanwo <github@xuanwo.io>
LanceDB Python SDK
A Python library for LanceDB.
Installation
pip install lancedb
Pre-Haswell x86_64 hosts: lancedb-compat
The default lancedb wheel targets x86-64-haswell (AVX2 + FMA + F16C) for full performance on modern hardware. Pre-Haswell hosts — Intel Sandy Bridge / Ivy Bridge / Westmere; AMD Bulldozer / Piledriver / Steamroller — don't have AVX2 and crash with Illegal instruction at import lancedb.
For those hosts, install the lancedb-compat package instead:
pip install lancedb-compat
Same Python API (import lancedb works as usual). The compat wheel is compiled at the x86-64-v2 baseline (Nehalem-class) and uses runtime SIMD dispatch in the embedded lance crate to pick the right kernel tier (scalar / AVX / AVX+FMA / AVX2+FMA / AVX-512) at load time, so it still goes fast on modern hardware while running cleanly on the pre-Haswell silicon. Use lance.simd_info() from Python to verify which tier was selected.
lancedb and lancedb-compat install to the same lancedb/ namespace and conflict at install time. Pick one. To switch, pip uninstall lancedb first, then pip install lancedb-compat (or vice-versa).
If you need a custom baseline (or lancedb-compat isn't yet published for your platform), build from source with the override:
RUSTFLAGS="-C target-cpu=x86-64-v2" maturin build --release
pip install ./target/wheels/lancedb-*.whl
Preview Releases
Stable releases are created about every 2 weeks. For the latest features and bug fixes, you can install the preview release. These releases receive the same level of testing as stable releases, but are not guaranteed to be available for more than 6 months after they are released. Once your application is stable, we recommend switching to stable releases.
pip install --pre --extra-index-url https://pypi.fury.io/lancedb/ lancedb
Threading in CPU-limited containers
LanceDB uses separate pools for compute work and storage I/O. On a container with two visible CPUs, current releases intentionally use one compute worker by default; no manual configuration is needed. If every query logs an I/O core reservation warning on a two-CPU container, upgrade from LanceDB 0.21.1 or earlier.
The two commonly tuned environment variables control different resources:
LANCE_CPU_THREADSoverrides the number of compute workers. One worker is the appropriate setting for a two-CPU container when an explicit override is needed.LANCE_IO_THREADScontrols concurrent storage operations, not reserved CPU cores. Its default can be greater than the number of CPUs because I/O workers spend much of their time waiting for storage.
Keep the defaults unless measurements show that the workload benefits from an override. See the Lance threading model for the current defaults and tuning guidance.
Usage
Basic Example
import lancedb
db = lancedb.connect('<PATH_TO_LANCEDB_DATASET>')
table = db.open_table('my_table')
results = table.search([0.1, 0.3]).limit(20).to_list()
print(results)
Development
See CONTRIBUTING.md for information on how to contribute to LanceDB.