pingcap/tidb · error

Out of Unknown Resource Quota!

Error message

Out of Unknown Resource Quota!

What it means

The default arm of the same switch in globalPanicOnExceed (pkg/executor/select.go): the triggered tracker's Label() is none of GlobalStorage/GlobalMemory/GlobalAnalyzeMemory, so TiDB cannot name the resource and panics with 'Out of Unknown Resource Quota!'. Reaching it means a quota-exceeded action was attached to a global tracker that forgot to set a recognized label - an internal invariant break, not a user workload property.

Source

Thrown at pkg/executor/select.go:182

}

// Action panics when storage usage exceeds storage quota.
func (a *globalPanicOnExceed) Action(t *memory.Tracker) {
	a.mutex.Lock()
	defer a.mutex.Unlock()
	msg := ""
	switch t.Label() {
	case memory.LabelForGlobalStorage:
		msg = globalPanicStorageExceed
	case memory.LabelForGlobalMemory:
		msg = globalPanicMemoryExceed
	case memory.LabelForGlobalAnalyzeMemory:
		msg = globalPanicAnalyzeMemoryExceed
	default:
		msg = "Out of Unknown Resource Quota!"
	}
	// TODO(hawkingrei): should return error instead.
	panic(msg)
}

// GetPriority get the priority of the Action
func (*globalPanicOnExceed) GetPriority() int64 {
	return memory.DefPanicPriority
}

// SelectLockExec represents a select lock executor.
// It is built from the "SELECT .. FOR UPDATE" or the "SELECT .. LOCK IN SHARE MODE" statement.
// For "SELECT .. FOR UPDATE" statement, it locks every row key from source Executor.
// After the execution, the keys are buffered in transaction, and will be sent to KV
// when doing commit. If there is any key already locked by another transaction,
// the transaction will rollback and retry.
type SelectLockExec struct {
	exec.BaseExecutor

	Lock *ast.SelectLockInfo
	keys []kv.Key

View on GitHub (pinned to d01f9615c1)

Solutions

1. Upgrade to a patched TiDB version where every global quota tracker sets a recognized label.
2. Collect the panic stack (it identifies the tracker) and report it at github.com/pingcap/tidb.
3. As a stopgap, relax global memory/storage quotas so no tracker hits the panic action.

// this panic indicates an internal bug; catch at the driver level, record the
// stack, and restart/reconnect the session - no query-level fix exists
if strings.Contains(err.Error(), "Out of Unknown Resource Quota!") {
    log.Stack(err) // report upstream; retry on a fresh connection

When it happens

Trigger: Any global tracker with a missing/unmapped label reaching its quota and running the panic action: essentially only when new TiDB code registers a tracker without LabelForGlobal* or an old binary loads mismatched tracker state. No supported user configuration produces it.

Common situations: Nightly or early releases where a new global quota shipped without a label case; plugins/experimental features registering global trackers; essentially never in supported GA versions.

Related errors

• Out Of Global Memory Limit!
• Out Of Global Analyze Memory Limit!
• Out Of Quota For Local Temporary Space!
• fail to create iterator
• TiFlash does not support vector index with pedicates

AI-assisted analysis of pingcap/tidb@d01f9615c1 (2026-08-15). Data as JSON: /api/errors/4c25c2d041968d98. Report an issue: GitHub.