# Background Tasks { #background-tasks }

You can define background tasks to be run *after* returning a response.

This is useful for operations that need to happen after a request, but that the client doesn't really have to be waiting for the operation to complete before receiving the response.

This includes, for example:

* Email notifications sent after performing an action:

	objAPI ObjectLayer

	stats expiryStats
}

// PendingTasks returns the number of pending ILM expiry tasks.
func (es *expiryState) PendingTasks() int {
	w := es.workers.Load()
	if w == nil || len(*w) == 0 {
		return 0
	}
	var tasks int
	for _, wrkr := range *w {
		tasks += len(wrkr)
	}
	return tasks
}

// enqueueTierJournalEntry enqueues a tier journal entry referring to a remote

    end

    operation ->> client: Return response to client
    Note over client,operation: Response is already sent, can't change it anymore
    opt Tasks
        operation -->> tasks: Send background tasks
    end
    opt Raise other exception
        tasks -->> tasks: Handle exceptions in the background task code
    end
```

/// info

* Then it returns the **response**.

/// note | Technical Details

If you have dependencies with `yield`, the exit code will run *after* the middleware.

If there were any background tasks (covered in the [Background Tasks](background-tasks.md){.internal-link target=_blank} section, you will see it later), they will run *after* all the middleware.

///

## Create a middleware { #create-a-middleware }

    val name = this.withLock { nextQueueName++ }
    return TaskQueue(this, "Q$name")
  }

  /**
   * Returns a snapshot of queues that currently have tasks scheduled. The task runner does not
   * necessarily track queues that have no tasks scheduled.
   */
  fun activeQueues(): List<TaskQueue> {
    this.withLock {
      return busyQueues + readyQueues
    }
  }

  fun cancelAll() {

├── Smb2LeaseKey.java            - 16-byte lease key management
├── Smb2LeaseState.java          - Lease state flags (R, H, W)
└── LeaseManager.java            - Central lease management
```

#### 1.2 Implementation Tasks
- [ ] Define lease state constants (SMB2_LEASE_READ, SMB2_LEASE_HANDLE, SMB2_LEASE_WRITE)
- [ ] Implement lease key generation and management
- [ ] Add lease context to Create request/response

        return "-D" + Constants.FESS_THUMBNAIL_PATH + "=" + baseDir.getAbsolutePath();
    }

    /**
     * Stores thumbnail generation tasks to the queue for processing.
     *
     * @param taskList list of thumbnail tasks to store
     */
    protected void storeQueue(final List<Tuple3<String, String, String>> taskList) {
        final FessConfig fessConfig = ComponentUtil.getFessConfig();

        this.scheduler = Executors.newScheduledThreadPool(3); // Increased for async notifications
        this.rpcClient = rpcClient;

        // Schedule periodic tasks
        schedulePeriodicTasks();
    }

    /**
     * Schedules periodic tasks for heartbeat and registration monitoring.
     */
    private void schedulePeriodicTasks() {
        // Heartbeat monitoring

fs.s3a.fast.upload.active.blocks=2048 # Number of parallel uploads
fs.s3a.fast.upload.buffer=disk # Use disk as the buffer for uploads
fs.s3a.fast.upload=true # Turn on fast upload mode
fs.s3a.max.total.tasks=2048 # Maximum number of parallel tasks
fs.s3a.multipart.size=512M # Size of each multipart chunk
fs.s3a.multipart.threshold=512M # Size before using multipart uploads
fs.s3a.socket.recv.buffer=65536 # Read socket buffer hint

   *   <li>When you reduce the number of buckets, you can accept that the most recently added
   *       buckets will be removed first. More concretely, if you are dividing traffic among tasks,
   *       you can decrease the number of tasks from 15 and 10, killing off the final 5 tasks, and
   *       {@code consistentHash} will handle it. If, however, you are dividing traffic among