SLEEP

The SLEEP statement is used to introduce a delay or pause in the execution of a query or a batch of queries for a specific amount of time.

Statement syntax

SLEEP @duration;

Example usage

The following query shows example usage of this statement.

-- Sleep one second
SLEEP 1s;
-- Sleep 100 milliseconds
SLEEP 100ms;

For more dynamic usage of sleep, see SurrealDB's sleep function.

SLEEP during parallel operations

A SLEEP statement does not interfere with operations that are underway in the background, such as a DEFINE INDEX statement using the CONCURRENTLY clause.

CREATE |user:1..=50000| RETURN NONE;
UPDATE user SET name = id.id() RETURN NONE;
DEFINE INDEX unique_name ON TABLE user FIELDS name UNIQUE CONCURRENTLY;
INFO FOR INDEX unique_name ON TABLE user;
SLEEP 50ms;
INFO FOR INDEX unique_name ON TABLE user;
SLEEP 50ms;
INFO FOR INDEX unique_name ON TABLE user;
SLEEP 50ms;
INFO FOR INDEX unique_name ON TABLE user;

-------- Query 1 --------
{
	building: {
		compacting: false,
		status: 'started'
	}
}

-------- Query 2 --------
{
	building: {
		compacting: false,
		initial: 9016,
		pending: 0,
		status: 'indexing'
	}
}

-------- Query 3 --------
{
	building: {
		compacting: false,
		initial: 17266,
		pending: 0,
		status: 'indexing'
	}
}

-------- Query 4 --------
{
	building: {
		compacting: false,
		initial: 25766,
		pending: 0,
		status: 'indexing'
	}
}

Use cases

SLEEP can be useful in a small number of situations, such as:

• •

  Testing and debugging: can be used to understand how concurrent transactions interact, test how systems handle timeouts and delays, simulate behaviour in more distant regions with longer latency

• •

  Throttling: can be used to throttle the execution of operations to prevent the database from being overwhelmed by too many requests at once

• •

  Security measures: can be used to slow down the response rate of login attempts to mitigate the risk of brute force attacks