Add Set A Statement Timeout Threshold For A Session as a postgres til

postgres/set-a-statement-timeout-threshold-for-a-session.md

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+# Set A Statement Timeout Threshold For A Session
+
+The `statement_timeout` variable is used to tell the PostgreSQL server that you
+want it to terminate statements (queries and transactions) that run past the
+specified threshold. This is a great way to [prevent runaway
+queries](https://blog.crunchydata.com/blog/control-runaway-postgres-queries-with-statement-timeout)
+in a production environment.
+
+You can set this threshold with a `set` statement. It can take an integer
+argument of milliseconds. Here I set it to a timeout of 1 minute.
+
+```sql
+> set statement_timeout = 60000;
+SET
+> show statement_timeout;
+ statement_timeout
+-------------------
+ 1min
+(1 row)
+```
+
+This will set the `statement_timeout` for the duration of the session. It won't
+effect other sessions.
+
+You can also set the threshold with a string argument which allows you to
+include a unit of time. Here I set it to 30 seconds.
+
+```sql
+> set statement_timeout = '30s';
+SET
+> show statement_timeout;
+ statement_timeout
+-------------------
+ 30s
+(1 row)
+```
+
+Now that the `statement_timeout` is set to `30s`, I can run a query that I know
+will exceed that threshold
+([`pg_sleep`](https://www.postgresql.org/docs/current/functions-datetime.html#FUNCTIONS-DATETIME-DELAY)).
+
+```sql
+> select pg_sleep(31);
+ERROR:  canceling statement due to statement timeout
+Time: 30001.997 ms (00:30.002)
+```
+
+After 30 seconds have passed, the Postgres server will interrupt the query.