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

Error message

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

What it means

CacheStore::info returns cachestore statistics; on worker nodes it is implemented as a panic! stub (cache_rocksstore.rs:2080) because cache info is served by the master. Calling it on a worker means stats/admin traffic was pointed at a node that cannot answer it.

Source

Thrown at rust/cubestore/cubestore/src/cachestore/cache_rocksstore.rs:2080

    async fn queue_result_blocking(
        &self,
        _key: QueueKey,
        _timeout: u64,
    ) -> Result<Option<QueueResultResponse>, CubeError> {
        panic!("CacheStore cannot be used on the worker node! queue_result_blocking was used.")
    }

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

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

    async fn info(&self) -> Result<CachestoreInfo, CubeError> {
        panic!("CacheStore cannot be used on the worker node! info was used.")
    }

    async fn eviction(&self) -> Result<EvictionResult, CubeError> {
        panic!("CacheStore cannot be used on the worker node! eviction was used.")
    }

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

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

    async fn rocksdb_properties(&self) -> Result<Vec<RocksPropertyRow>, CubeError> {
        panic!("CacheStore cannot be used on the worker node! rocksdb_properties was used.")
    }

View on GitHub (pinned to 7d981676b3)

Solutions

Query cachestore info from the master node only
Update monitoring/scraping configs to target the master endpoint
Guard the info-collection code path with a node-role check

Example fix

// before
let info = worker_store.info().await?;
// after
let info = master_client.info().await?;

Defensive patterns

Strategy: validation

Validate before calling

if !is_master { return Err(CubeError::internal("cache info is master-only")); }
let info = master_client.info().await?;

Type guard

fn serves_info(store: &dyn CacheStore) -> bool { node_role == NodeRole::Master }

Try / catch

let info = std::panic::catch_unwind(AssertUnwindSafe(|| master_client.info())).map_err(|_| CubeError::internal("info called on worker node"))?;

Prevention

Scrape cachestore metrics only from the master
Configure dashboards with master endpoints
Add role checks in stats collectors
Document that info() panics on workers

When it happens

Trigger: Calling CacheStore::info() on a worker-node CacheStore instance (cache_rocksstore.rs:2080).

Common situations: Monitoring dashboards scraping cachestore info from all nodes including workers; dev/test setups running master-only APIs against a worker process.

Related errors

AI-assisted analysis of cube-js/cube@7d981676b3 (2026-09-02). Data as JSON: /api/errors/9612c6f50f59f2de. Report an issue: GitHub.