> For the complete documentation index, see [llms.txt](https://ploegert.gitbook.io/til/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://ploegert.gitbook.io/til/programmy/linux/is-app-installed/queries/prevent-a-query-from-running-too-long.md).

# Prevent A Query From Running Too Long

A number of different factors can effect how long a query takes to run. Certainly the size of a table and the complexity of the query play a big role. Locking can really slow a query down by making it wait to get started. A series of competing queries that induce table locking can grind things to a halt.

If you don't want queries in a particular connection being allowed to wait or run too long, you can set a timeout.

```sql
set statement_timeout to '500';
```

That will ensure that any statement run in that connection will be terminated if it takes longer than 500ms.

You can also specify a unit:

```sql
set statement_timeout to '15s';
```

That will enforce statement timeout of 15 seconds.

See the [docs](https://www.postgresql.org/docs/current/runtime-config-client.html) for more details.