Delete removes items from the Lake tree: datasources, databases, schemas, tables and folders. Use it to clear out objects you no longer need. A delete cannot be undone, so the confirmation counts what will go before you commit.
Delete from the toolbar
Click a row to mark it, or turn on Batch select and tick several items. Ticking a parent also selects everything under it. See The Lake tree and Batch edit and organise.
Click Delete in the tree toolbar. The button is greyed out while nothing is selected, or while a delete is already running.
Read Delete Selected Items?. Items to delete ({total}): counts the selection by kind: data source(s), database(s), schema(s) and table(s). The dialog warns that This action cannot be undone.
The dialog checks what depends on the selection. When something does, the confirm button reads Delete anyway. For what the check covers and what its notices mean, see Deleting a table with dependants.
Confirm. The selected rows show a spinner and ignore clicks and keys while the delete runs.
Delete from a row's menu
Right-click the row.
Choose Delete.
Read the confirmation. It names the item's kind, for example: This action will permanently remove this data source. This operation cannot be undone.
Click Delete to confirm.
A folder's menu offers only Delete. On workflow rows the action is hidden; manage those in the Workflows view instead. See Workflows in the Lake.
What a delete removes
Selecting a datasource, database or schema collects everything under it, so its tables go with the parent item. You do not delete the tables one by one first.
While a Deployed or Not deployed filter is on, Delete acts on tables only: datasources, databases, schemas and folders in your selection are skipped. Clear the filter first if you meant to remove them. See Search and filter the Lake.
A folder can be deleted only when it is empty. While it still holds datasources, the delete is refused with Cannot delete folder and Please remove or move all data sources from this folder first. Move the datasources out first.
A deleted datasource closes its open tab. If you were viewing that tab, the Lake returns to the datasource list. The source panel beside the tree closes too when it was showing that datasource.
The tree keeps removed items hidden from updates that arrive while the deletion settles, so a refresh does not bring them back.
Warning
Objects that depend on the tables you delete are not removed with them; they may break until you fix them. Check the dialog's list before you confirm.
Retry a failed deletion
When some tables fail, only the successful ones are removed. A red badge then appears next to Delete with the number of failures:
Click the badge to open Failed Deletions; its subtitle reads {n} table(s) failed to delete.
Each row shows the table and its error message. When the table's name is unknown, the row shows its id, prefixed with #.
Retry delete retries that one table; a spinner runs while it works. The row leaves the list when it succeeds, or shows its refreshed error when it fails again.
Edit opens the table so you can fix the cause. Copy error copies the error message, showing a check briefly when copied.
Failures are reported per table, and retrying one does not touch the others. If the request itself fails, the notification shows the server's reason; a failed folder delete falls back to Failed to delete folder. For the message texts, see Lake troubleshooting.
Permissions
Deleting needs Remove Lake Objects. Without it, you can still see the action, but the request is refused. See Who can do what in the Lake.
Questions, answered
What do the counts in the delete dialog mean?
They show what the confirmation will remove, grouped by kind, so you can see how many datasources, databases, schemas and tables are about to go. A selection can report lines such as 1 data source(s) and 2 table(s). Read the counts before you confirm.
What happens to an open tab when I delete its datasource?
Its tab closes. If it was the tab you were viewing, the Lake goes back to the datasource list. If the source panel beside the tree was showing that datasource, it closes with it.
If I delete a schema, are its tables deleted too?
Yes. Selecting a datasource, database or schema collects everything under it, and its tables are removed with it. You do not need to delete each table first, and the confirmation counts everything that will go.
Does deleting a table remove its loaded data?
Yes. A deleted table leaves the Lake together with its loaded data. To clear the data but keep the table, use Truncate or Drop instead: Truncate empties the table and keeps it, and Drop clears the data while keeping the definition so you can deploy again. See Run, stop and troubleshoot loads.
If you need the table in the Lake again, import it from its source and set it up as before; see Import tables and Deploy tables.
Why is the Delete button greyed out?
The toolbar button is active only when there is something to delete. It is greyed out while nothing is selected, and while a delete is already running. Select an item and let the running delete settle, then try again.
Why did only part of my selection get deleted?
Some tables failed to delete, and only the successful ones were removed. The failures wait behind the red badge next to Delete: open Failed Deletions and click Retry delete on each failed table. See Lake troubleshooting.
Why is there no Delete on a workflow row?
Workflow rows are managed in the Workflows view, so the tree hides Delete for them. There you can delete a workflow once it holds no tables; system-generated workflows cannot be deleted at all. See Workflows in the Lake.
Will a deleted item reappear when the tree refreshes?
No. After you confirm, the tree keeps the removed items hidden from updates that arrive while the deletion settles, so a refresh does not bring them back.