SLEEP()

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

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:

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

     sql <!-- validator-ignore-exec --> mysql> select connection_id(); +-----------------+ | connection_id() | +-----------------+ | 1476 | +-----------------+ 1 row in set (0.03 sec) mysql> select sleep(200);

  2. At this point, open a new session, interrupt session 1, and run the following command.

     sql <!-- validator-ignore-exec --> mysql> kill 1463; Query OK, 0 rows affected (0.00 sec)

  3. 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

```sql -- 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) ```