MemPalace/mempalace · error · ValueError

metadatas length {len(metadatas)} does not match ids length

Error message

metadatas length {len(metadatas)} does not match ids length {n}

What it means

Error "metadatas length {len(metadatas)} does not match ids length {n}" thrown in MemPalace/mempalace.

Source

Thrown at mempalace/backends/pgvector.py:304

                        return True
                stack.append(value)
            elif isinstance(value, list):
                stack.extend(item for item in value if isinstance(item, dict))
    return False


def _validate_write_batch(
    *,
    documents: list[str],
    ids: list[str],
    metadatas: Optional[list[dict]],
    embeddings: Optional[list[list[float]]],
) -> None:
    n = len(ids)
    if len(documents) != n:
        raise ValueError(f"documents length {len(documents)} does not match ids length {n}")
    if metadatas is not None and len(metadatas) != n:
        raise ValueError(f"metadatas length {len(metadatas)} does not match ids length {n}")
    if embeddings is not None and len(embeddings) != n:
        raise ValueError(f"embeddings length {len(embeddings)} does not match ids length {n}")


def _as_vector_array(vector: list[float]) -> np.ndarray:
    arr = np.asarray(vector, dtype=np.float32)
    if arr.ndim != 1 or arr.size == 0:
        raise ValueError("embedding must be a non-empty 1D vector")
    return arr


def _normalize_vectors(embeddings: list[list[float]]) -> tuple[list[list[float]], int]:
    vectors = []
    dims = set()
    for embedding in embeddings:
        arr = _as_vector_array(embedding)
        vectors.append(arr.astype(float).tolist())
        dims.add(int(arr.size))

View on GitHub (pinned to 06cb6987f0)

Solutions

1. Pass one metadata dict per id; align metadatas and ids list lengths

When it happens

Trigger: Thrown at mempalace/backends/pgvector.py:304 when the library encounters an invalid state.

Common situations: Metadatas list length diverged from ids list length.

AI-assisted analysis of MemPalace/mempalace@06cb6987f0 (2026-08-15). Data as JSON: /api/errors/a585c7de83b9c283. Report an issue: GitHub.