SLEEP()

Description

Sleeps (pauses) for the number of seconds given by the duration argument, then returns 0.

Syntax

>
SLEEP(duration)

Arguments

Arguments	Description
duration	Required. The number of seconds. The `duration` may have a fractional part. The `duration` is not allowed NULL or negative.

Returned Value

When sleep returns normally (without interruption), it returns 0.

When SLEEP() returns 1 (with interruption or time out), the query returns no error.

For example:

In session 1, execute the following command to query the current connection_id and execute the SLEEP() function:

mysql> select connection_id();
+-----------------+
| connection_id() |
+-----------------+
|            1476 |
+-----------------+
1 row in set (0.03 sec)
mysql> select sleep(200);

At this point, open a new session, interrupt session 1, and run the following command.
```
mysql> kill 1463;
Query OK, 0 rows affected (0.00 sec)
```

Check the query result of session 1:

mysql> select sleep(200);
+------------+
| sleep(200) |
+------------+
|          1 |
+------------+
1 row in set (26.50 sec)

When SLEEP() returns an error (part of a query is uninterrupted). For example:

mysql> SELECT 1 FROM t1 WHERE SLEEP(1000);
ERROR 20101 (HY000): internal error: pipeline closed unexpectedly

Examples

-- without interruption
mysql> SELECT SLEEP(1);
+----------+
| sleep(1) |
+----------+
|        0 |
+----------+
1 row in set (1.01 sec)

-- without interruption
mysql> SELECT SLEEP(1000);
+-------------+
| sleep(1000) |
+-------------+
|           0 |
+-------------+
1 row in set (18 min 20.87 sec)

create table t1 (a int,b int);
insert into t1 values (1,1),(1,null);
mysql> select sleep(a) from t1;
+----------+
| sleep(a) |
+----------+
|        0 |
|        0 |
+----------+
2 rows in set (2.01 sec)