feat: add table branch support (#3490)

### Description

Adds first-class support for table branches across the Rust core and the
Python and TypeScript SDKs.

Rust

```rust
use lance::dataset::refs::Ref;

// Create a branch from main and write to it — main is untouched.
let exp = table.create_branch("exp", Ref::Version(None, None)).await?;
exp.add(batches).await?;

// Reopen the branch later: check out from a table, or open it directly.
let exp = table.checkout_branch("exp").await?;
let exp = db.open_table("items").branch("exp").execute().await?;

let branches = table.list_branches().await?;
table.delete_branch("exp").await?;
```

Python

```python
# Create a branch from main and write to it
branch = await table.branches.create("exp", from_ref="main")
await branch.add(data)

# Reopen the branch later: check out from a table, or open it directly.
branch = await table.branches.checkout("exp")
branch = await db.open_table("items", branch="exp")

await table.branches.list()
await table.branches.delete("exp")
```

TypeScript

```typescript
const branches = await table.branches();

// Create a branch from main and write to it
const branch = await branches.create("exp");
await branch.add(data);

// Reopen the branch later: check out from a table, or open it directly.
const checkedOut = await branches.checkout("exp");
const opened = await db.openTable("items", undefined, { branch: "exp" });

await branches.list();
await branches.delete("exp");
```

### Testing
- Added unit tests
- ran smoke tests against python and typescript sdks on local machine


### Next steps
- Add RemoteTable support
- Add Branch Comparison support
- Merge Branching support
This commit is contained in:
Brendan Clement
2026-06-08 16:26:46 -07:00
committed by GitHub
parent 3e25f584eb
commit 53517b3aaa
24 changed files with 1275 additions and 35 deletions

View File

@@ -226,6 +226,9 @@ class Table:
async def close_lsm_writers(self) -> None: ...
@property
def tags(self) -> Tags: ...
@property
def branches(self) -> Branches: ...
def current_branch(self) -> Optional[str]: ...
def query(self) -> Query: ...
def take_offsets(self, offsets: list[int]) -> TakeQuery: ...
def take_row_ids(self, row_ids: list[int]) -> TakeQuery: ...
@@ -238,6 +241,17 @@ class Tags:
async def delete(self, tag: str): ...
async def update(self, tag: str, version: int): ...
class Branches:
async def list(self) -> Dict[str, Any]: ...
async def create(
self,
name: str,
from_ref: Optional[str] = None,
from_version: Optional[int] = None,
) -> Table: ...
async def checkout(self, name: str) -> Table: ...
async def delete(self, name: str) -> None: ...
class IndexConfig:
name: str
index_type: str

View File

@@ -416,6 +416,7 @@ class DBConnection(EnforceOverrides):
namespace_path: Optional[List[str]] = None,
storage_options: Optional[Dict[str, str]] = None,
index_cache_size: Optional[int] = None,
branch: Optional[str] = None,
) -> Table:
"""Open a Lance Table in the database.
@@ -444,6 +445,9 @@ class DBConnection(EnforceOverrides):
connection will be inherited by the table, but can be overridden here.
See available options at
<https://docs.lancedb.com/storage/>
branch: str, optional
If provided, open a handle scoped to this branch instead of the
default branch. Reads and writes operate in the branch's context.
Returns
-------
@@ -958,6 +962,7 @@ class LanceDBConnection(DBConnection):
namespace_path: Optional[List[str]] = None,
storage_options: Optional[Dict[str, str]] = None,
index_cache_size: Optional[int] = None,
branch: Optional[str] = None,
) -> LanceTable:
"""Open a table in the database.
@@ -968,6 +973,9 @@ class LanceDBConnection(DBConnection):
namespace_path: List[str], optional
The namespace to open the table from. When non-empty, the
table is resolved through the directory namespace client.
branch: str, optional
If provided, open a handle scoped to this branch instead of the
default branch. Reads and writes operate in the branch's context.
Returns
-------
@@ -987,20 +995,24 @@ class LanceDBConnection(DBConnection):
)
if namespace_path:
return self._namespace_conn().open_table(
tbl = self._namespace_conn().open_table(
name,
namespace_path=namespace_path,
storage_options=storage_options,
index_cache_size=index_cache_size,
)
else:
tbl = LanceTable.open(
self,
name,
namespace_path=namespace_path,
storage_options=storage_options,
index_cache_size=index_cache_size,
)
return LanceTable.open(
self,
name,
namespace_path=namespace_path,
storage_options=storage_options,
index_cache_size=index_cache_size,
)
if branch is not None:
return tbl.branches.checkout(branch)
return tbl
def clone_table(
self,
@@ -1641,6 +1653,7 @@ class AsyncConnection(object):
location: Optional[str] = None,
namespace_client: Optional[Any] = None,
managed_versioning: Optional[bool] = None,
branch: Optional[str] = None,
) -> AsyncTable:
"""Open a Lance Table in the database.
@@ -1676,6 +1689,9 @@ class AsyncConnection(object):
managed_versioning: bool, optional
Whether managed versioning is enabled for this table. If provided,
avoids a redundant describe_table call when namespace_client is set.
branch: str, optional
If provided, open a handle scoped to this branch instead of the
default branch. Reads and writes operate in the branch's context.
Returns
-------
@@ -1692,7 +1708,10 @@ class AsyncConnection(object):
namespace_client=namespace_client,
managed_versioning=managed_versioning,
)
return AsyncTable(table)
tbl = AsyncTable(table)
if branch is not None:
return await tbl.branches.checkout(branch)
return tbl
async def clone_table(
self,

View File

@@ -549,6 +549,7 @@ class LanceNamespaceDBConnection(DBConnection):
namespace_path: Optional[List[str]] = None,
storage_options: Optional[Dict[str, str]] = None,
index_cache_size: Optional[int] = None,
branch: Optional[str] = None,
) -> Table:
if namespace_path is None:
namespace_path = []
@@ -567,7 +568,7 @@ class LanceNamespaceDBConnection(DBConnection):
raise TableNotFoundError(f"Table not found: {'$'.join(table_id)}")
raise
return LanceTable(
tbl = LanceTable(
self,
name,
namespace_path=namespace_path,
@@ -575,6 +576,9 @@ class LanceNamespaceDBConnection(DBConnection):
pushdown_operations=self._namespace_client_pushdown_operations,
_async=async_table,
)
if branch is not None:
return tbl.branches.checkout(branch)
return tbl
@override
def drop_table(self, name: str, namespace_path: Optional[List[str]] = None):
@@ -984,6 +988,7 @@ class AsyncLanceNamespaceDBConnection:
namespace_path: Optional[List[str]] = None,
storage_options: Optional[Dict[str, str]] = None,
index_cache_size: Optional[int] = None,
branch: Optional[str] = None,
) -> AsyncTable:
"""Open an existing table from the namespace."""
if namespace_path is None:
@@ -1000,6 +1005,8 @@ class AsyncLanceNamespaceDBConnection:
table_id = namespace_path + [name]
raise TableNotFoundError(f"Table not found: {'$'.join(table_id)}")
raise
if branch is not None:
table = await table.branches.checkout(branch)
return table._set_namespace_context(
namespace_path=namespace_path,
namespace_client=self._namespace_client,

View File

@@ -383,6 +383,7 @@ class RemoteDBConnection(DBConnection):
namespace_path: Optional[List[str]] = None,
storage_options: Optional[Dict[str, str]] = None,
index_cache_size: Optional[int] = None,
branch: Optional[str] = None,
) -> Table:
"""Open a Lance Table in the database.
@@ -400,6 +401,9 @@ class RemoteDBConnection(DBConnection):
"""
from .table import RemoteTable
if branch is not None:
raise NotImplementedError("branching is not yet supported on remote tables")
if namespace_path is None:
namespace_path = []
if index_cache_size is not None:

View File

@@ -784,6 +784,15 @@ class Table(ABC):
"""
raise NotImplementedError
@property
def branches(self) -> "Branches":
"""Branch management for the table.
Branches are isolated, writable lines of history forked from another
branch (or version). Writes on a branch do not affect ``main``.
"""
raise NotImplementedError
def __len__(self) -> int:
"""The number of rows in this Table"""
return self.count_rows(None)
@@ -2112,22 +2121,27 @@ class LanceTable(Table):
"Please install with `pip install pylance`."
)
branch = self.current_branch()
version = None if branch is not None else self.version
if self._namespace_client is not None:
table_id = self._namespace_path + [self.name]
return lance.dataset(
version=self.version,
ds = lance.dataset(
version=version,
storage_options=self._conn.storage_options,
namespace_client=self._namespace_client,
table_id=table_id,
**kwargs,
)
return lance.dataset(
self._dataset_path,
version=self.version,
storage_options=self._conn.storage_options,
**kwargs,
)
else:
ds = lance.dataset(
self._dataset_path,
version=version,
storage_options=self._conn.storage_options,
**kwargs,
)
if branch is not None:
ds = ds.checkout_version((branch, self.version))
return ds
@property
def schema(self) -> pa.Schema:
@@ -2193,6 +2207,19 @@ class LanceTable(Table):
"""
return Tags(self._table)
@property
def branches(self) -> "Branches":
"""Branch management for the table.
``create``/``checkout`` return a new table handle scoped to the branch;
writes on it do not affect ``main``.
"""
return Branches(self)
def current_branch(self) -> Optional[str]:
"""The branch this table handle is scoped to, or ``None`` for ``main``."""
return self._table.current_branch()
def checkout(self, version: Union[int, str]):
"""Checkout a version of the table. This is an in-place operation.
@@ -3457,8 +3484,14 @@ class LanceTable(Table):
batch_size: Optional[int] = None,
timeout: Optional[timedelta] = None,
) -> pa.RecordBatchReader:
if _should_push_down_query_table(
self._namespace_client, self._pushdown_operations
# Branch queries run locally: the server-side query protocol can't
# carry a branch yet.
# TODO: push down server-side once it can (with remote table support).
if (
_should_push_down_query_table(
self._namespace_client, self._pushdown_operations
)
and self.current_branch() is None
):
from lancedb.namespace import _execute_server_side_query
@@ -4385,12 +4418,20 @@ class AsyncTable:
"Please install with `pip install pylance`."
)
return lance.dataset(
# lance.dataset() can't open a branch directly, so open the base table
# and check out the branch ref (a None branch resolves to main).
branch = self.current_branch()
table_version = await self.version()
version = None if branch is not None else table_version
ds = lance.dataset(
await self.uri(),
version=await self.version(),
version=version,
storage_options=await self.latest_storage_options(),
**kwargs,
)
if branch is not None:
ds = ds.checkout_version((branch, table_version))
return ds
async def to_pandas(self, blob_mode: BlobMode = "lazy", **kwargs) -> "pd.DataFrame":
"""Return the table as a pandas DataFrame.
@@ -5521,6 +5562,19 @@ class AsyncTable:
"""
return AsyncTags(self._inner)
@property
def branches(self) -> AsyncBranches:
"""Branch management for the table.
Branches are isolated, writable lines of history forked from another
branch (or version). Writes on a branch do not affect ``main``.
"""
return AsyncBranches(self._inner)
def current_branch(self) -> Optional[str]:
"""The branch this table handle is scoped to, or ``None`` for ``main``."""
return self._inner.current_branch()
async def optimize(
self,
*,
@@ -5853,6 +5907,65 @@ class Tags:
LOOP.run(self._table.tags.update(tag, version))
class Branches:
"""
Table branch manager.
"""
def __init__(self, parent: "LanceTable"):
self._parent = parent
self._table = parent._table
def list(self) -> Dict[str, Any]:
"""List all branches, mapping name to branch metadata."""
return LOOP.run(self._table.branches.list())
def create(
self,
name: str,
from_ref: Optional[str] = None,
from_version: Optional[int] = None,
) -> "LanceTable":
"""Create a branch and return a handle scoped to it.
Parameters
----------
name: str
Name of the new branch.
from_ref: str, optional
Source branch to fork from. Defaults to ``main``.
from_version: int, optional
A specific version on ``from_ref`` to fork from. Defaults to latest.
"""
async_table = LOOP.run(
self._table.branches.create(name, from_ref, from_version)
)
return self._wrap(async_table)
def checkout(self, name: str) -> "LanceTable":
"""Check out an existing branch and return a handle scoped to it."""
async_table = LOOP.run(self._table.branches.checkout(name))
return self._wrap(async_table)
def delete(self, name: str) -> None:
"""Delete a branch."""
LOOP.run(self._table.branches.delete(name))
def _wrap(self, async_table: "AsyncTable") -> "LanceTable":
# Reuse the parent's connection + namespace context; from_inner would drop
# it and break identity/query routing for namespace-backed tables.
parent = self._parent
return LanceTable(
parent._conn,
async_table.name,
namespace_path=parent._namespace_path,
namespace_client=parent._namespace_client,
pushdown_operations=parent._pushdown_operations,
location=parent._location,
_async=async_table,
)
class AsyncTags:
"""
Async table tag manager.
@@ -5920,3 +6033,47 @@ class AsyncTags:
The new table version to tag.
"""
await self._table.tags.update(tag, version)
class AsyncBranches:
"""Async table branch manager."""
def __init__(self, table):
self._table = table
async def list(self) -> Dict[str, Any]:
"""List all branches, mapping name to branch metadata."""
return await self._table.branches.list()
async def create(
self,
name: str,
from_ref: Optional[str] = None,
from_version: Optional[int] = None,
) -> "AsyncTable":
"""Create a branch and return a handle scoped to it.
Parameters
----------
name: str
Name of the new branch.
from_ref: str, optional
Source branch to fork from. Defaults to ``main``.
from_version: int, optional
A specific version on ``from_ref`` to fork from. Defaults to latest.
"""
# "main" and None are two spellings of the root branch in lance; normalize
# so from_ref="main" behaves identically to the default.
if from_ref == "main":
from_ref = None
inner = await self._table.branches.create(name, from_ref, from_version)
return AsyncTable(inner)
async def checkout(self, name: str) -> "AsyncTable":
"""Check out an existing branch and return a handle scoped to it."""
inner = await self._table.branches.checkout(name)
return AsyncTable(inner)
async def delete(self, name: str) -> None:
"""Delete a branch."""
await self._table.branches.delete(name)

View File

@@ -28,6 +28,10 @@ def _ipc_file(table: pa.Table = PUSHDOWN_DATA) -> bytes:
class _FailingSyncInner:
name = "hist"
def current_branch(self):
# The pushdown gate only routes server-side when on the default branch.
return None
async def schema(self):
return PUSHDOWN_DATA.schema

View File

@@ -928,6 +928,160 @@ async def test_async_tags(mem_db_async: AsyncConnection):
)
def test_branches(tmp_path):
db = lancedb.connect(tmp_path, read_consistency_interval=timedelta(0))
table = db.create_table(
"test",
data=[
{"vector": [3.1, 4.1], "item": "foo", "price": 10.0},
{"vector": [5.9, 26.5], "item": "bar", "price": 20.0},
],
)
assert table.count_rows() == 2
# fork an isolated, writable branch from main
branch = table.branches.create("exp")
assert branch.count_rows() == 2
branch.add(data=[{"vector": [10.0, 11.0], "item": "baz", "price": 30.0}])
# writes on the branch do not touch main
assert branch.count_rows() == 3
assert table.count_rows() == 2
# the branch is listed, with main (None) as its parent
branches = table.branches.list()
assert "exp" in branches
assert branches["exp"]["parent_branch"] is None
# from_ref="main" is equivalent to the default
table.branches.create("exp2", from_ref="main")
assert table.branches.list()["exp2"]["parent_branch"] is None
# checkout returns a handle scoped to the branch's latest
checked_out = table.branches.checkout("exp")
assert checked_out.count_rows() == 3
# delete removes it
table.branches.delete("exp")
table.branches.delete("exp2")
assert "exp" not in table.branches.list()
def test_branch_handle_tracks_concurrent_writes(tmp_path):
db = lancedb.connect(tmp_path, read_consistency_interval=timedelta(0))
table = db.create_table("t", [{"id": 1}])
# two independent handles on the same branch
writer = table.branches.create("exp")
reader = db.open_table("t", branch="exp")
assert reader.count_rows() == 1
# a concurrent write on the branch is visible to the other handle
writer.add([{"id": 2}])
assert reader.count_rows() == 2
# main is unaffected
assert table.count_rows() == 1
def test_branch_name_validation(tmp_path):
db = lancedb.connect(tmp_path)
table = db.create_table("t", [{"id": 1}])
with pytest.raises(ValueError, match="non-empty"):
table.branches.create("")
with pytest.raises(ValueError, match="non-empty"):
table.branches.checkout("")
with pytest.raises(ValueError, match="non-empty"):
table.branches.delete("")
def test_branches_preserve_namespace(tmp_path):
pytest.importorskip(
"lance"
) # namespace_path routes through lance's DirectoryNamespace
db = lancedb.connect(tmp_path)
table = db.create_table("t", [{"id": 1}], namespace_path=["ns1"])
assert table.namespace == ["ns1"]
branch = table.branches.create("exp")
assert branch.namespace == ["ns1"]
assert branch.id == table.id
# opening the branch directly also preserves namespace identity
opened = db.open_table("t", namespace_path=["ns1"], branch="exp")
assert opened.namespace == ["ns1"]
def test_open_table_with_branch(tmp_path):
db = lancedb.connect(tmp_path)
table = db.create_table("t", [{"i": 1}])
table.branches.create("exp").add([{"i": 2}])
# open_table(branch=...) returns a handle scoped to the branch
assert db.open_table("t", branch="exp").count_rows() == 2
# opening without branch still tracks main
assert db.open_table("t").count_rows() == 1
@pytest.mark.asyncio
async def test_async_namespace_open_table_with_branch(tmp_path):
pytest.importorskip("lance") # "dir" impl is lance.namespace.DirectoryNamespace
db = lancedb.connect_namespace_async("dir", {"root": str(tmp_path)})
await db.create_namespace(["ns1"])
table = await db.create_table("t", [{"id": 1}], namespace_path=["ns1"])
branch = await table.branches.create("exp")
await branch.add([{"id": 2}])
# open_table(branch=...) on the async namespace connection must work
opened = await db.open_table("t", namespace_path=["ns1"], branch="exp")
assert await opened.count_rows() == 2
def test_branch_to_lance_targets_branch(tmp_path):
pytest.importorskip("lance")
db = lancedb.connect(tmp_path)
table = db.create_table("t", [{"i": 1}])
branch = table.branches.create("exp")
branch.add([{"i": 2}]) # branch: 2 rows, main: 1 row
assert branch.to_lance().count_rows() == 2
assert table.to_lance().count_rows() == 1
@pytest.mark.asyncio
async def test_async_branches(tmp_path):
db = await lancedb.connect_async(tmp_path)
table = await db.create_table(
"test",
data=[
{"vector": [3.1, 4.1], "item": "foo", "price": 10.0},
{"vector": [5.9, 26.5], "item": "bar", "price": 20.0},
],
)
assert await table.count_rows() == 2
branch = await table.branches.create("exp")
assert await branch.count_rows() == 2
await branch.add(data=[{"vector": [10.0, 11.0], "item": "baz", "price": 30.0}])
assert await branch.count_rows() == 3
assert await table.count_rows() == 2
branches = await table.branches.list()
assert "exp" in branches
assert branches["exp"]["parent_branch"] is None
await table.branches.create("exp2", from_ref="main")
assert (await table.branches.list())["exp2"]["parent_branch"] is None
checked_out = await table.branches.checkout("exp")
assert await checked_out.count_rows() == 3
await table.branches.delete("exp")
await table.branches.delete("exp2")
assert "exp" not in await table.branches.list()
@patch("lancedb.table.AsyncTable.create_index")
def test_create_index_method(mock_create_index, mem_db: DBConnection):
table = mem_db.create_table(

View File

@@ -17,7 +17,7 @@ use arrow::{
};
use lancedb::table::{
AddDataMode, ColumnAlteration, Duration, FieldMetadataUpdate, NewColumnTransform,
OptimizeAction, OptimizeOptions, Table as LanceDbTable,
OptimizeAction, OptimizeOptions, Ref, Table as LanceDbTable,
};
use pyo3::{
Bound, FromPyObject, Py, PyAny, PyRef, PyResult, Python,
@@ -860,6 +860,15 @@ impl Table {
Ok(Tags::new(self.inner_ref()?.clone()))
}
pub fn current_branch(&self) -> PyResult<Option<String>> {
Ok(self.inner_ref()?.current_branch())
}
#[getter]
pub fn branches(&self) -> PyResult<Branches> {
Ok(Branches::new(self.inner_ref()?.clone()))
}
#[pyo3(signature = (offsets))]
pub fn take_offsets(self_: PyRef<'_, Self>, offsets: Vec<u64>) -> PyResult<TakeQuery> {
Ok(TakeQuery::new(
@@ -1261,3 +1270,66 @@ impl Tags {
})
}
}
#[pyclass]
pub struct Branches {
inner: LanceDbTable,
}
impl Branches {
pub fn new(table: LanceDbTable) -> Self {
Self { inner: table }
}
}
#[pymethods]
impl Branches {
pub fn list(self_: PyRef<'_, Self>) -> PyResult<Bound<'_, PyAny>> {
let inner = self_.inner.clone();
future_into_py(self_.py(), async move {
let res = inner.list_branches().await.infer_error()?;
Python::attach(|py| {
let py_dict = PyDict::new(py);
for (name, contents) in res {
let value = PyDict::new(py);
value.set_item("parent_branch", contents.parent_branch)?;
value.set_item("parent_version", contents.parent_version)?;
value.set_item("manifest_size", contents.manifest_size)?;
py_dict.set_item(name, value)?;
}
Ok(py_dict.unbind())
})
})
}
#[pyo3(signature = (name, from_ref=None, from_version=None))]
pub fn create(
self_: PyRef<'_, Self>,
name: String,
from_ref: Option<String>,
from_version: Option<u64>,
) -> PyResult<Bound<'_, PyAny>> {
let inner = self_.inner.clone();
future_into_py(self_.py(), async move {
let from = Ref::Version(from_ref, from_version);
let table = inner.create_branch(&name, from).await.infer_error()?;
Ok(Table::new(table))
})
}
pub fn checkout(self_: PyRef<'_, Self>, name: String) -> PyResult<Bound<'_, PyAny>> {
let inner = self_.inner.clone();
future_into_py(self_.py(), async move {
let table = inner.checkout_branch(&name).await.infer_error()?;
Ok(Table::new(table))
})
}
pub fn delete(self_: PyRef<'_, Self>, name: String) -> PyResult<Bound<'_, PyAny>> {
let inner = self_.inner.clone();
future_into_py(self_.py(), async move {
inner.delete_branch(&name).await.infer_error()?;
Ok(())
})
}
}