Jack Ye
9af7757053
Remote materialized-view creation currently expects a REST response containing a registry job ID, while refresh already submits SQL. Route both through the SQL query backend and preserve Python's synchronous and asynchronous return types. ### Query to Job mapping `SqlClient::submit_as_job()` submits an `ExecuteQueryRequest` through the same backend as `execute_query_async()`. Once submission succeeds, it retains the returned `Query` and starts one client-side task that consumes its result reader to completion. `Job::from_query_task()` wraps that task, its cached outcome, a single ID and a cancellation callback. Python exposes this as `Job[T]` or `AsyncJob[T]`. The existing `job_type` property maps SQL-backed handles to the new `"query"` kind. The shared `id` contains that query's UUID string, so Python callers can inspect it with `db.describe_query(job.id)` on the submitting connection. No separate `query_id`, backend enum or `type()` API is added. | Handle | `job_type` | `id` | Available lookup | | --- | --- | --- | --- | | SQL-backed | `"query"`, known at submission | Connection-scoped query UUID string | `describe_query(job.id)` | | Registry-backed | Existing server-reported kind, after `status()` or `refresh()` | Registry job ID string | Registry job APIs, descriptions and events | | Local | `None` | `None` | The current in-process handle | | Job concept | SQL-backed behavior | | --- | --- | | Submission | Await initial SQL submission before returning the handle. Submission errors propagate immediately. | | `status()` | Tracks the adapter task: running during result consumption/finalization, finished after both succeed, failed if either fails, or cancelled after cancellation. | | `wait()` | Returns the operation's typed terminal result. One task consumes the query reader once; repeated waits reuse its cached outcome without resubmitting SQL or reopening the reader. | | `cancel()` | Delegates to `Query.cancel()`. Rejected or unsupported cancellation leaves the task running; an accepted request stops the task. Cancelling a finished operation is a no-op. | | Registry details | Query-backed handles expose no registry description, event history, pause/resume or reattachment after a client restart. `refresh()` updates cached lifecycle state. | The Job tracks command completion rather than exposing SQL batches. A wait timeout does not cancel the query. Query IDs remain scoped to the submitting connection and cannot be used with registry APIs or as durable resume tokens. Python `describe_query()` accepts both UUID objects and the string `id` exposed by query-backed jobs. Rust, Python and TypeScript expose the same classification through their existing job-type accessors. ### Materialized-view operations - **CREATE:** Render `CREATE MATERIALIZED VIEW` with the view namespace and optional auto-refresh settings. After command completion, resolve the job to `None`. Synchronous creation waits on the job, then opens and returns the materialized view. - **REFRESH:** Submit `REFRESH MATERIALIZED VIEW` through the same adapter. After command completion, read the refreshed table's version and row count to construct the existing typed refresh result. Synchronous refresh waits on the same path. Remote creation requires the SQL service. Execution placement remains a server decision. REST endpoints are unchanged. The job guide documents the ID/job-type contract and query-backed limitations. Regression coverage exercises SQL submission, namespaces, refresh options, job-type/ID preservation through typed result mapping, repeated waits, failures and cancellation rejection. No local builds or tests were run.
LanceDB Python SDK
A Python library for LanceDB.
Installation
pip install lancedb
If no wheel is published for your platform, pip builds lancedb from the source distribution. That build needs a Rust toolchain and protoc (the Protocol Buffers compiler) on your PATH, and can take a while.
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
If you also need the optional lance Python API, install the pylance extra
and include the Lance preview index:
pip install --pre \
--extra-index-url https://pypi.fury.io/lancedb/ \
--extra-index-url https://pypi.fury.io/lance-format/ \
"lancedb[pylance]"
With uv, also select the best matching version across the indexes:
uv pip install --prerelease allow \
--index https://pypi.fury.io/lancedb/ \
--index https://pypi.fury.io/lance-format/ \
--index-strategy unsafe-best-match \
"lancedb[pylance]"
The LanceDB preview index contains old pylance releases; current Lance previews
are published to the lance-format index. By default, uv only considers versions
from the first index containing a package, which can select an old pylance or
backtrack to an older LanceDB release. unsafe-best-match searches all configured
indexes, like pip; use it only with indexes you trust. Install the extra rather
than an unconstrained pylance so LanceDB's minimum supported version is enforced.
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.