mirror of
https://github.com/ClickHouse/ClickHouse.git
synced 2024-11-16 20:53:27 +00:00
71 lines
2.6 KiB
Markdown
71 lines
2.6 KiB
Markdown
---
|
||
toc_priority: 46
|
||
toc_title: KILL
|
||
---
|
||
|
||
# KILL Statements {#kill-statements}
|
||
|
||
There are two kinds of kill statements: to kill a query and to kill a mutation
|
||
|
||
## KILL QUERY {#kill-query-statement}
|
||
|
||
``` sql
|
||
KILL QUERY [ON CLUSTER cluster]
|
||
WHERE <where expression to SELECT FROM system.processes query>
|
||
[SYNC|ASYNC|TEST]
|
||
[FORMAT format]
|
||
```
|
||
|
||
Attempts to forcibly terminate the currently running queries.
|
||
The queries to terminate are selected from the system.processes table using the criteria defined in the `WHERE` clause of the `KILL` query.
|
||
|
||
Examples:
|
||
|
||
``` sql
|
||
-- Forcibly terminates all queries with the specified query_id:
|
||
KILL QUERY WHERE query_id='2-857d-4a57-9ee0-327da5d60a90'
|
||
|
||
-- Synchronously terminates all queries run by 'username':
|
||
KILL QUERY WHERE user='username' SYNC
|
||
```
|
||
|
||
Read-only users can only stop their own queries.
|
||
|
||
By default, the asynchronous version of queries is used (`ASYNC`), which does not wait for confirmation that queries have stopped.
|
||
|
||
The synchronous version (`SYNC`) waits for all queries to stop and displays information about each process as it stops.
|
||
The response contains the `kill_status` column, which can take the following values:
|
||
|
||
1. `finished` – The query was terminated successfully.
|
||
2. `waiting` – Waiting for the query to end after sending it a signal to terminate.
|
||
3. The other values explain why the query can’t be stopped.
|
||
|
||
A test query (`TEST`) only checks the user’s rights and displays a list of queries to stop.
|
||
|
||
## KILL MUTATION {#kill-mutation}
|
||
|
||
``` sql
|
||
KILL MUTATION [ON CLUSTER cluster]
|
||
WHERE <where expression to SELECT FROM system.mutations query>
|
||
[TEST]
|
||
[FORMAT format]
|
||
```
|
||
|
||
Tries to cancel and remove [mutations](../../sql-reference/statements/alter/index.md#alter-mutations) that are currently executing. Mutations to cancel are selected from the [`system.mutations`](../../operations/system-tables/mutations.md#system_tables-mutations) table using the filter specified by the `WHERE` clause of the `KILL` query.
|
||
|
||
A test query (`TEST`) only checks the user’s rights and displays a list of mutations to stop.
|
||
|
||
Examples:
|
||
|
||
``` sql
|
||
-- Cancel and remove all mutations of the single table:
|
||
KILL MUTATION WHERE database = 'default' AND table = 'table'
|
||
|
||
-- Cancel the specific mutation:
|
||
KILL MUTATION WHERE database = 'default' AND table = 'table' AND mutation_id = 'mutation_3.txt'
|
||
```
|
||
|
||
The query is useful when a mutation is stuck and cannot finish (e.g. if some function in the mutation query throws an exception when applied to the data contained in the table).
|
||
|
||
Changes already made by the mutation are not rolled back.
|