**Source URL:** https://limited.veevavault.dev/medical/mdl/component-types/queue

**Class:** `metadata`

Spark messaging is a message notification system that allows for loosely coupled, asynchronous, near real-time integration between Vaults or external applications. Messages are processed by a queuing system to provide reliable delivery. Outbound messages are placed in an outbound queue, and delivered messages enter an inbound queue.

Learn about [Creating & Managing Queues in Vault Help](https://platform.veevavault.help/en/lr/53147).

| Attribute | Metadata | Description |
| --- | --- | --- |
| `label` | Type: String Max length: 60 | UI-friendly string in the Vault's base language. |
| `active` | Type: Boolean | Indicates whether the field is active. |
| `description` | Type: String Max length: 500 | The description of the queue. |
| `message_delivery_event_handler` | Type: ComponentReference | Specifies the optional Spark message delivery event handler to use for outbound queues. References the `Messagedeliveryeventhandler` component. |
| `message_delivery_event_handler_user` | Type: String Max length: 1500 | Indicate the user who will process Spark message delivery event handler actions for the outbound queue. Applicable only when `message_delivery_event_handler` is configured. |
| `message_processor` | Type: ComponentReference | References the `Messageprocessor` component. |
| `message_processor_user` | Type: String Max length: 1500 | Indicates the user who will process messages delivered to an *Inbound* queue. |
| `rollback_on_error` | Type: Boolean | Indicates whether this queue will continue the transaction when a message fails to enter the queue. If the `type` is `job`, Vault ignores this attribute. |
| `sequential` | Type: Boolean | Indicates if the messages intended for this queue must be processed sequentially, meaning one after another in the order they are received. If the `type` is `job`, Vault ignores this attribute. |
| `type` | Type: Enum **Required** Allowed values: inbound; outbound; job | Specifies whether the queue is *Outbound* (sends messages), or *Inbound* (receives messages). |

### Queueconnection

| Attribute | Metadata | Description |
| --- | --- | --- |
| `label` | Type: String Max length: 60 | UI-friendly string in the Vault's base language. |
| `active` | Type: Boolean | Indicates whether the field is active. |
| `connection_name` | Type: String **Required** Max length: 40 | The name of the connection. |
| `connection_type` | Type: String Max length: 40 | The type of queue connection. |
| `deliver_to_queue` | Type: String Max length: 1500 | The name of the connected queue. |

### Supported Operations

| Operation | Support |
| --- | --- |
| Create | Yes |
| Recreate | Yes |
| Alter | Yes |
| Drop | Yes |
| Rename | Yes |
| Describe | Yes |
| Generate Recreate | Yes |
| Queryable | Yes |

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