Enterprise

# Delete data

> Delete the samples of channels in a time range with the Python and TypeScript clients, and learn when the Core rejects a delete.

Delete the samples of one or more channels in a time range. The channels stay, so you can write new samples to the time range. To delete a channel, see [Rename and delete channels](https://docs.synnaxlabs.com/reference/channels/rename-and-delete).

## Delete a time range

Give `delete` the channels and the time range. The time range includes its start and excludes its end.

[Enterprise](https://docs.synnaxlabs.com/reference/get-started/editions "Needs Synnax Enterprise")

**Python**

```python
from datetime import datetime, timezone

import synnax as sy

tr = sy.TimeRange(
    datetime(2026, 10, 3, 12, 0, tzinfo=timezone.utc),
    datetime(2026, 10, 3, 12, 5, tzinfo=timezone.utc),
)
client.delete(["temperature", "pressure"], tr)
```

**TypeScript**

```typescript
import { TimeRange } from "@synnaxlabs/client";

const tr = new TimeRange(
  new Date("2026-10-03T12:00:00Z"),
  new Date("2026-10-03T12:05:00Z"),
);
await client.delete(["temperature", "pressure"], tr);
```

A delete cannot be undone. After `delete` returns, reads do not return the samples. The Core frees the disk space only after a file holds a large amount of deleted data, so a small delete can leave the disk use the same.

A delete of a time range with no data does nothing and raises no error.

> A name with characters other than letters, digits, and underscores is a regular expression. The Core deletes the data of each channel whose name matches it. For example, `sensor_.*` matches all channels whose names start with `sensor_`.

## When the Core rejects a delete

The Core rejects a delete in these cases:

* **An index channel with data that depends on it** -> you cannot delete samples of an index channel while a data channel that it indexes has samples in the time range. Delete the data channels first, or in the same call as the index channel.
* **An open writer** -> you cannot delete a time range that an open writer can write to. Close the writer first.
* **A channel key that does not exist** -> the Core deletes nothing and raises a not found error. A channel name that does not exist raises no error: the Core deletes nothing for that name.
* **No permission** -> your user needs permission to delete the data of each channel. Users with the Viewer role cannot delete data.

[Enterprise](https://docs.synnaxlabs.com/reference/get-started/editions "Needs Synnax Enterprise")

**Python**

```python
# temperature has samples in the range, so this delete fails.
client.delete(["time"], tr)

# This delete works, because the data channels are in the same call.
client.delete(["temperature", "pressure", "time"], tr)
```

**TypeScript**

```typescript
// temperature has samples in the range, so this delete fails.
await client.delete(["time"], tr);

// This delete works, because the data channels are in the same call.
await client.delete(["temperature", "pressure", "time"], tr);
```

In this example, `time` indexes `temperature` and `pressure`. In one call, the Core deletes the data channels before the index channels, whatever their order in the list.

A delete is not atomic. When one channel fails, the Core can already have deleted the data of other channels in the call.