test(rust): guard parallel compaction fragment reservation

docs/src/python/python.md

@@ -17,25 +17,6 @@ The general flow of using the API is:
 pip install lancedb
 ```
 
-The core package does not require PyLance. When you need access to the underlying
-Lance dataset or GPU-accelerated indexing, add the `pylance` extra to the
-distribution you already installed.
-
-For the standard distribution:
-
-```shell
-pip install "lancedb[pylance]"
-```
-
-For the pre-Haswell compatibility distribution:
-
-```shell
-pip install "lancedb-compat[pylance]"
-```
-
-Use only the extra matching your installed distribution. Do not install both
-distributions because they share the `lancedb` namespace.
-
 The following methods describe the synchronous API client. There
 is also an [asynchronous API client](#connections-asynchronous).
 

python/README.md

@@ -8,25 +8,6 @@ A Python library for [LanceDB](https://github.com/lancedb/lancedb).
 pip install lancedb
 ```
 
-The core package does not require PyLance. When you need access to the underlying
-Lance dataset or GPU-accelerated indexing, add the `pylance` extra to the
-distribution you already installed.
-
-For the standard distribution:
-
-```bash
-pip install "lancedb[pylance]"
-```
-
-For the pre-Haswell compatibility distribution:
-
-```bash
-pip install "lancedb-compat[pylance]"
-```
-
-Use only the extra matching your installed distribution. Do not install both
-distributions because they share the `lancedb` namespace.
-
 ### 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`.

python/python/lancedb/table.py

@@ -117,14 +117,6 @@ _MODEL_BACKED_TOKENIZER_ERRORS = (
     "Failed to initialize default tokenizer",
 )
 
-_PYLANCE_INSTALL_ERROR = (
-    "The lance library is required to use this function. Install the PyLance "
-    "extra for the distribution already installed: "
-    '`pip install "lancedb[pylance]"` for `lancedb`, or '
-    '`pip install "lancedb-compat[pylance]"` for `lancedb-compat`. '
-    "Do not install both distributions because they share the `lancedb` namespace."
-)
-
 
 def _add_unique_note(exception: BaseException, note: str) -> None:
     existing_notes = getattr(exception, "__notes__", ()) or ()
@@ -2257,7 +2249,10 @@ class LanceTable(Table):
         try:
             import lance
         except ImportError:
-            raise ImportError(_PYLANCE_INSTALL_ERROR)
+            raise ImportError(
+                "The lance library is required to use this function. "
+                "Please install with `pip install pylance`."
+            )
 
         branch = self.current_branch()
         version = None if branch is not None else self.version
@@ -4762,7 +4757,10 @@ class AsyncTable:
         try:
             import lance
         except ImportError:
-            raise ImportError(_PYLANCE_INSTALL_ERROR)
+            raise ImportError(
+                "The lance library is required to use this function. "
+                "Please install with `pip install pylance`."
+            )
 
         # 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).

python/python/tests/test_import.py

@@ -1,30 +0,0 @@
-# SPDX-License-Identifier: Apache-2.0
-# SPDX-FileCopyrightText: Copyright The LanceDB Authors
-
-import subprocess
-import sys
-
-
-def test_import_lancedb_without_pylance():
-    script = """
-import sys
-
-
-class BlockLanceImports:
-    def find_spec(self, fullname, path=None, target=None):
-        if fullname == "lance" or fullname.startswith("lance."):
-            raise ModuleNotFoundError(f"blocked optional dependency: {fullname}")
-        return None
-
-
-sys.meta_path.insert(0, BlockLanceImports())
-import lancedb
-"""
-
-    result = subprocess.run(
-        [sys.executable, "-c", script],
-        capture_output=True,
-        text=True,
-    )
-
-    assert result.returncode == 0, result.stderr

python/python/tests/test_table.py

@@ -1258,24 +1258,6 @@ def test_branch_to_lance_targets_branch(tmp_path):
     assert table.to_lance().count_rows() == 1
 
 
-def _assert_pylance_install_error(error: ImportError):
-    message = str(error)
-    assert 'pip install "lancedb[pylance]"' in message
-    assert 'pip install "lancedb-compat[pylance]"' in message
-    assert "distribution already installed" in message
-    assert "Do not install both distributions" in message
-
-
-def test_to_lance_recommends_pylance_extra(tmp_db):
-    table = tmp_db.create_table("t", [{"i": 1}])
-
-    with patch("builtins.__import__", side_effect=ImportError):
-        with pytest.raises(ImportError) as exc_info:
-            table.to_lance()
-
-    _assert_pylance_install_error(exc_info.value)
-
-
 @pytest.mark.asyncio
 async def test_async_to_lance(tmp_path):
     pytest.importorskip("lance")
@@ -1287,18 +1269,6 @@ async def test_async_to_lance(tmp_path):
     assert dataset.count_rows() == 1
 
 
-@pytest.mark.asyncio
-async def test_async_to_lance_recommends_pylance_extra(tmp_path):
-    db = await lancedb.connect_async(tmp_path)
-    table = await db.create_table("t", [{"i": 1}])
-
-    with patch("builtins.__import__", side_effect=ImportError):
-        with pytest.raises(ImportError) as exc_info:
-            await table.to_lance()
-
-    _assert_pylance_install_error(exc_info.value)
-
-
 @pytest.mark.asyncio
 async def test_async_branch_to_lance_targets_branch(tmp_path):
     pytest.importorskip("lance")

rust/lancedb/src/table/optimize.rs

@@ -304,6 +304,68 @@ mod tests {
         assert_eq!(all_values, expected);
     }
 
+    #[tokio::test]
+    async fn test_parallel_compaction_reserves_fragment_ids_once() {
+        let conn = connect("memory://").execute().await.unwrap();
+        let schema = Arc::new(Schema::new(vec![Field::new("i", DataType::Int32, false)]));
+        let batch =
+            RecordBatch::try_new(schema, vec![Arc::new(Int32Array::from_iter_values(0..10))])
+                .unwrap();
+
+        let table = conn
+            .create_table("test_parallel_compaction", batch.clone())
+            .execute()
+            .await
+            .unwrap();
+
+        // Create 64 fragments. With a 20-row target, compaction plans 32 tasks,
+        // which is more than the commit retry limit that used to be exhausted
+        // when each parallel task reserved fragment IDs independently.
+        for _ in 1..64 {
+            table.add(batch.clone()).execute().await.unwrap();
+        }
+
+        // Legacy row IDs require fragment IDs before an index can be remapped.
+        assert!(
+            !table
+                .as_native()
+                .unwrap()
+                .manifest()
+                .await
+                .unwrap()
+                .uses_stable_row_ids()
+        );
+        table
+            .create_index(&["i"], Index::BTree(BTreeIndexBuilder::default()))
+            .execute()
+            .await
+            .unwrap();
+
+        let version_before = table.version().await.unwrap();
+        let stats = table
+            .optimize(OptimizeAction::Compact {
+                options: CompactionOptions {
+                    target_rows_per_fragment: 20,
+                    num_threads: Some(64),
+                    ..Default::default()
+                },
+                remap_options: None,
+            })
+            .await
+            .unwrap()
+            .compaction
+            .unwrap();
+
+        assert_eq!(stats.fragments_removed, 64);
+        assert_eq!(stats.fragments_added, 32);
+        assert_eq!(table.count_rows(None).await.unwrap(), 640);
+        assert_eq!(
+            table.version().await.unwrap(),
+            version_before + 2,
+            "parallel compaction should use one fragment reservation commit and one rewrite commit"
+        );
+    }
+
     #[tokio::test]
     async fn test_optimize_prune_versions() {
         let conn = connect("memory://").execute().await.unwrap();