go-redis/redis · error

failed to mark connection as unusable: %w

Error message

failed to mark connection as unusable: %w

What it means

Error "failed to mark connection as unusable: %w" thrown in go-redis/redis.

Source

Thrown at internal/pool/conn.go:909

	// But in some edge cases or tests, it might be in IDLE or CREATED state
	// The pool will detect this state change and preserve it (not overwrite with IDLE)
	// Use predefined slice to avoid allocation
	finalState, err := cn.stateMachine.TryTransition(validFromCreatedInUseOrIdle, StateUnusable)
	if err != nil {
		// Check if already in UNUSABLE state (race condition or retry)
		// ShouldHandoff should be false now, but check just in case
		if finalState == StateUnusable && !cn.ShouldHandoff() {
			// Already unusable - this is fine, keep the new handoff state
			return nil
		}
		// Restore the original handoff state only if nothing else changed it
		// since our CAS above. A concurrent handoff worker may have completed
		// the handoff and run ClearHandoffState in this window; a plain Store
		// would clobber that, resurrecting ShouldHandoff=true and wedging the
		// connection so it can never be acquired again. The CAS leaves the
		// worker's state intact when it has taken over.
		cn.handoffStateAtomic.CompareAndSwap(newState, currentState)
		return fmt.Errorf("failed to mark connection as unusable: %w", err)
	}
	return nil
}

// GetID returns the unique identifier for this connection.
func (cn *Conn) GetID() uint64 {
	return cn.id
}

// GetStateMachine returns the connection's state machine for advanced state management.
// This is primarily used by internal packages like maintnotifications for handoff processing.
func (cn *Conn) GetStateMachine() *ConnStateMachine {
	return cn.stateMachine
}

// TryAcquire attempts to acquire the connection for use.
// This is an optimized inline method for the hot path (Get operation).
//

View on GitHub (pinned to 36d97525cd)

Solutions

1. Retry the operation on a fresh connection; the original conn could not be marked unusable
2. Check the wrapped error for pool-level issues (pool closed, conn already removed)

When it happens

Trigger: Thrown at internal/pool/conn.go:909 when the library encounters an invalid state.

Common situations: Let the pool own conn state transitions; do not hold conn references across operations.

AI-assisted analysis of go-redis/redis@36d97525cd (2026-08-06). Data as JSON: /data/errors/658862f692a1cf89.json. Report an issue: GitHub.