xai-org/x-algorithm · error · ValueError

enable_stale_post is unsupported on grpc_recsys, which does

Error message

enable_stale_post is unsupported on grpc_recsys, which does not transport per-post feature arrays (int64/bool/categorical/float)

What it means

The grpc_recsys dataset path builds a PhoenixGrpcDataset which does not transport per-post feature arrays (int64/bool/categorical/float). Setting enable_stale_post=True in mparams for a grpc_recsys config is therefore rejected at dataset construction time.

Source

Thrown at phoenix/xrex/configs/data_feeds.py:229

        history_seq_len=mparams["history_seq_len"],
        candidate_seq_len=mparams["candidate_seq_len"],
        input_vocab_size=mparams["input_vocab_size"],
        num_continuous_actions=mparams["num_continuous_actions"],
        num_negatives_per_example=mparams.get("num_negatives_per_example", 1),
        num_kafka_partitions=1024,
        output_vocab_size=mparams["output_vocab_size"],
        multimodal_embedding_type=mparams.get("multimodal_embedding_type"),
        use_post_sid=use_post_sid,
        sid_num_levels=sid_num_levels,
        compute_post_unexplored_label=mparams.get("compute_post_unexplored_label", False),
        enable_stale_post=mparams.get("enable_stale_post", False),
    )


def _ranking_grpc_recsys(mparams, hash_table, use_post_sid, sid_num_levels, config_name):
    del config_name
    if mparams.get("enable_stale_post", False):
        raise ValueError(
            "enable_stale_post is unsupported on grpc_recsys, which does not transport per-post feature arrays (int64/bool/categorical/float)"
        )
    return PhoenixGrpcDataset(
        hash_table=hash_table,
        history_seq_len=mparams["history_seq_len"],
        candidate_seq_len=mparams["candidate_seq_len"],
        server_address=_GRPC_DATALOADER_ADDRESS,
        input_vocab_size=mparams["input_vocab_size"],
        pad_token=PAD_TOKEN,
        output_vocab_size=mparams["output_vocab_size"],
        num_continuous_actions=mparams["num_continuous_actions"],
        num_negatives_per_example=mparams.get("num_negatives_per_example", 1),
        num_data_loaders=8,
        num_kafka_partitions=1024,
        multimodal_embedding_type=mparams.get("multimodal_embedding_type"),
        use_post_sid=use_post_sid,
        sid_num_levels=sid_num_levels,
    )

View on GitHub (pinned to 24c60942c5)

Solutions

Set enable_stale_post: False (or remove the key — it defaults to False) in the grpc_recsys config's mparams
If stale posts are required, switch dataset_type to a family that transports per-post feature arrays (e.g. aggregated_kafka)
Grep the target dataset class before enabling optional features: confirm the constructor accepts enable_stale_post

Example fix

# before
MODEL_CFGS = {..., "dataset_type": "grpc_recsys", "enable_stale_post": True}

# after
MODEL_CFGS = {..., "dataset_type": "grpc_recsys"}  # enable_stale_post defaults to False

Defensive patterns

Strategy: validation

Validate before calling

def validate_mparams(mparams: dict, dataset_type: str) -> None:
    if dataset_type == "grpc_recsys" and mparams.get("enable_stale_post", False):
        raise SystemExit(
            "enable_stale_post is not supported on grpc_recsys; remove it or switch dataset_type"
        )

Type guard

def supports_stale_post(dataset_type: str) -> bool:
    return dataset_type != "grpc_recsys"

Try / catch

try:
    ds = _make_dataset(mparams, dataset_type, hash_table, config_name)
except ValueError as e:
    if "enable_stale_post" in str(e):
        mparams = {k: v for k, v in mparams.items() if k != "enable_stale_post"}
        ds = _make_dataset(mparams, dataset_type, hash_table, config_name)  # degrade gracefully
    else:
        raise

Prevention

Keep per-dataset-type option whitelists instead of one shared mparams blob
When copying configs between dataset families, diff supported feature flags first
Document in each dataset class which mparams it consumes

When it happens

Trigger: Building a grpc_recsys dataset (via _ranking_grpc_recsys, typically through the RANKING_DATASET_FACTORIES registry in _make_dataset) with mparams containing enable_stale_post: True.

Common situations: Copying a config block from a kafka/offline dataset family that supports stale posts into a grpc_recsys config; flipping enable_stale_post globally for an experiment without checking per-dataset support; merging config defaults that assume all dataset types share features.

Related errors

AI-assisted analysis of xai-org/x-algorithm@24c60942c5 (2026-08-28). Data as JSON: /api/errors/139823737cd0eafd. Report an issue: GitHub.