CacheStore cannot be used on the worker node! queue_list was

Error message

CacheStore cannot be used on the worker node! queue_list was used.

What it means

queue_list returns queue items with optional status filtering, priority sorting and payload inclusion; it reads metastore-owned queue tables. CacheStore panics on workers because they hold no queue data.

Source

Thrown at rust/cubestore/cubestore/src/cachestore/cache_rocksstore.rs:2027

    async fn queue_to_cancel(
        &self,
        _prefix: String,
        _orphaned_timeout: Option<u32>,
        _heartbeat_timeout: Option<u32>,
    ) -> Result<Vec<IdRow<QueueItem>>, CubeError> {
        panic!("CacheStore cannot be used on the worker node! queue_to_cancel was used.")
    }

    async fn queue_list(
        &self,
        _prefix: String,
        _status_filter: Option<QueueItemStatus>,
        _priority_sort: bool,
        _with_payload: bool,
        _caller_process_id: Option<String>,
    ) -> Result<Vec<QueueListItem>, CubeError> {
        panic!("CacheStore cannot be used on the worker node! queue_list was used.")
    }

    async fn queue_get(&self, _key: QueueKey) -> Result<Option<QueueGetResponse>, CubeError> {
        panic!("CacheStore cannot be used on the worker node! queue_get was used.")
    }

    async fn queue_cancel(&self, _key: QueueKey) -> Result<Option<QueueCancelResponse>, CubeError> {
        panic!("CacheStore cannot be used on the worker node! queue_cancel was used.")
    }

    async fn queue_heartbeat(&self, _key: QueueKey) -> Result<(), CubeError> {
        panic!("CacheStore cannot be used on the worker node! queue_heartbeat_by_id was used.")
    }

    async fn queue_retrieve_by_path(
        &self,
        _path: String,
        _allow_concurrency: u32,

View on GitHub (pinned to 7d981676b3)

Solutions

Point queue inspection tools at the metastore node.
Restrict queue list APIs to the metastore in any proxy/load-balancer config.
Verify node role via CubeStore status endpoints before querying queue state.
Update client libraries to accept separate metastore vs store addresses.

Example fix

// before: monitor queries worker
monitor.connect('worker-0:3030').queueList(prefix);
// after
monitor.connect('metastore-0:3030').queueList(prefix);

Defensive patterns

Strategy: validation

Validate before calling

if !is_metastore(node) {
    return Err(CubeError::internal("queue_list requires the metastore node"));
}
let items = node.queueList(prefix, status, sort, with_payload, caller).await?;

Type guard

fn is_metastore(node: &CubeStoreNode) -> bool {
    matches!(node.role(), NodeRole::Metastore)
}

Prevention

Point monitoring dashboards at the metastore endpoint.
Don't put metastore queue reads behind round-robin DNS including workers.
Surface node role in monitoring metadata to catch misconfig early.

When it happens

Trigger: Listing queue items (queue_list with prefix/status filter/priority_sort/with_payload/caller_process_id) against a CubeStore worker node.

Common situations: Monitoring UIs or CLI tools querying a worker address to view the queue; round-robin DNS balancing metastore API reads onto workers.

Related errors

AI-assisted analysis of cube-js/cube@7d981676b3 (2026-09-02). Data as JSON: /api/errors/c294b54e1dcc8916. Report an issue: GitHub.