fix(lancedb): treat a lance spill failure as retryable

src/everos/core/persistence/lancedb/repository.py

@@ -208,6 +208,23 @@ def _remove_empty_index_dirs(
     return removed
 
 
+_TRANSIENT_EXECUTION_MARKERS = ("Spill has sent an error",)
+"""Substrings of lance error messages that name a query-execution failure a
+retry clears. ``LanceError(IO): Execution error: Spill has sent an error`` is
+DataFusion's sort / merge spill to the OS temp dir failing mid-query; lancedb
+raises it as a bare ``RuntimeError``. Seen only on the Windows soak box under
+nine concurrent clients (187 / 180 / 34 times over three runs), never on an
+idle box, and the same row projected fine on the next attempt — yet the worker
+filed every one as unrecoverable, so ~200 md files per run needed a manual
+``cascade fix``. Match the exact phrase: a generic IO error (disk full, file
+gone) must stay permanent."""
+
+
+def _is_transient_execution_error(exc: BaseException) -> bool:
+    text = str(exc)
+    return any(marker in text for marker in _TRANSIENT_EXECUTION_MARKERS)
+
+
 class LanceRepoBase[T: BaseLanceTable]:
     """Generic CRUD repository for one LanceDB table.
 
@@ -296,6 +313,19 @@ async def _deadline(self, budget: float, op: str) -> AsyncIterator[None]:
             raise VectorStoreBusyError(
                 f"{op} on table {self.table_name!r} exceeded its {budget:g}s deadline"
             ) from exc
+        except RuntimeError as exc:
+            if not _is_transient_execution_error(exc):
+                raise
+            logger.warning(
+                "lancedb_transient_execution_error",
+                table=self.table_name,
+                op=op,
+                error=str(exc)[:200],
+            )
+            raise VectorStoreBusyError(
+                f"{op} on table {self.table_name!r} hit a transient lance "
+                f"execution error: {exc}"
+            ) from exc
 
     @asynccontextmanager
     async def _locked(self, budget: float, op: str) -> AsyncIterator[None]:

tests/unit/test_core/test_persistence/test_lancedb/test_transient_execution_errors.py

@@ -0,0 +1,47 @@
+"""A lance query-execution failure that a retry clears must reach the cascade
+worker as :class:`VectorStoreBusyError` (retried with backoff), not as a bare
+``RuntimeError`` (filed as unrecoverable, needing a manual ``cascade fix``).
+"""
+
+from __future__ import annotations
+
+from typing import ClassVar
+
+import pytest
+
+from everos.core.errors import VectorStoreBusyError
+from everos.core.persistence.lancedb import BaseLanceTable, LanceRepoBase
+from everos.core.persistence.lancedb import repository as repo_mod
+
+_SPILL = (
+    "lance error: LanceError(IO): Execution error: Spill has sent an error, "
+    "C:\\Users\\x\\everos-src\\.venv\\Lib\\site-packages\\lance\\..."
+)
+
+
+class _Note(BaseLanceTable):
+    TABLE_NAME: ClassVar[str] = "_note"
+    id: str
+
+
+class _Repo(LanceRepoBase[_Note]):
+    schema = _Note
+
+
+def test_only_the_spill_phrase_counts_as_transient() -> None:
+    assert repo_mod._is_transient_execution_error(RuntimeError(_SPILL))
+    assert not repo_mod._is_transient_execution_error(
+        RuntimeError("lance error: LanceError(IO): No space left on device")
+    )
+
+
+async def test_spill_failure_inside_a_read_becomes_a_busy_error() -> None:
+    with pytest.raises(VectorStoreBusyError, match="transient lance execution"):
+        async with _Repo()._deadline(1.0, "find_where"):
+            raise RuntimeError(_SPILL)
+
+
+async def test_other_runtime_errors_still_propagate_unchanged() -> None:
+    with pytest.raises(RuntimeError, match="No space left"):
+        async with _Repo()._deadline(1.0, "find_where"):
+            raise RuntimeError("lance error: LanceError(IO): No space left on device")