mirror of
https://github.com/ClickHouse/ClickHouse.git
synced 2024-11-16 20:53:27 +00:00
23 lines
928 B
Markdown
23 lines
928 B
Markdown
---
|
|
slug: /en/sql-reference/statements/alter/apply-deleted-mask
|
|
sidebar_position: 46
|
|
sidebar_label: APPLY DELETED MASK
|
|
---
|
|
|
|
# Apply mask of deleted rows
|
|
|
|
``` sql
|
|
ALTER TABLE [db].name [ON CLUSTER cluster] APPLY DELETED MASK [IN PARTITION partition_id]
|
|
```
|
|
|
|
The command applies mask created by [lightweight delete](/docs/en/sql-reference/statements/delete) and forcefully removes rows marked as deleted from disk. This command is a heavyweight mutation, and it semantically equals to query ```ALTER TABLE [db].name DELETE WHERE _row_exists = 0```.
|
|
|
|
:::note
|
|
It only works for tables in the [`MergeTree`](../../../engines/table-engines/mergetree-family/mergetree.md) family (including [replicated](../../../engines/table-engines/mergetree-family/replication.md) tables).
|
|
:::
|
|
|
|
**See also**
|
|
|
|
- [Lightweight deletes](/docs/en/sql-reference/statements/delete)
|
|
- [Heavyweight deletes](/docs/en/sql-reference/statements/alter/delete.md)
|