# backup-ahead-of-clock

An event of the backup lies **more than an hour beyond the clock** of the server.

- **Route:** `restore-backup`
- **Description:** `backup is ahead of the clock: the event in line <line> is dated <time>, more than an hour beyond the clock of the server; restore it once the clock has caught up`
- **Details:** **`line`**, the number of the line in the request body that holds the event, counting from 1, heartbeats included, and **`value`**, the time of the event as the backup holds it.

## Why It Happens

The time of an event is **never earlier than the time of the event before it**, so while the clock of the server is behind the latest event, every new event takes the **time of the latest event**, see **[Watching the Clock](/docs/eventsourcingdb/logging-and-monitoring#watching-the-clock)**. A restored event dated far in the future, such as `9999-12-31`, would give its time to **every event written after the restore**, until the clock had caught up with it. So a **[restore](/docs/eventsourcingdb/backup-and-restore#compatibility)** checks every event of the backup against the clock of the server as it reads the event, and refuses one that lies **more than an hour beyond it**.

An hour covers the difference between the clocks of two servers, so a backup from a server whose clock ran **slightly ahead** still restores, and new events take the time of its latest event until the clock has caught up. A restore that fails this way removes what it has restored so far, so the database is empty again, see **[When a Restore Fails](/docs/eventsourcingdb/backup-and-restore#when-a-restore-fails)**.

## How to Fix It

Check the clock of the server and the time that `value` names. If the clock is behind, correct it, and restore the backup again. Otherwise, **restore the same backup once the clock has caught up**, as the description says; until then, resending the request fails the same way.

## Example

For a restore whose fifth line holds an event dated `9999-12-31T23:59:59.999999999Z`, EventSourcingDB answers with this error, as a line of the stream, and then ends the stream with its `end` item:

```json
{
  "type": "error",
  "data": {
    "code": "https://docs.eventsourcingdb.io/errors/backup-ahead-of-clock",
    "description": "backup is ahead of the clock: the event in line 5 is dated 9999-12-31T23:59:59.999999999Z, more than an hour beyond the clock of the server; restore it once the clock has caught up",
    "details": {
      "line": 5,
      "value": "9999-12-31T23:59:59.999999999Z"
    }
  }
}
```