UUID_SHORT

Syntax

UUID_SHORT()

Description

Returns a "short" universally unique identifier as a 64-bit unsigned integer (rather than a string-form 128-bit identifier as returned by the UUID() function).

The value of UUID_SHORT() is guaranteed to be unique if the following conditions hold:

  • The server_id of the current host is unique among your set of master and slave servers
  • server_id is between 0 and 255
  • You don't set back your system time for your server between mysqld restarts
  • You do not invoke UUID_SHORT() on average more than 16 million times per second between mysqld restarts

The UUID_SHORT() return value is constructed this way:

  (server_id & 255) << 56
+ (server_startup_time_in_seconds << 24)
+ incremented_variable++;

Statements using the UUID_SHORT() function are not safe for statement-based replication.

Examples

SELECT UUID_SHORT();
+-------------------+
| UUID_SHORT()      |
+-------------------+
| 21517162376069120 |
+-------------------+
create table t1 (a bigint unsigned default(uuid_short()) primary key);
insert into t1 values(),();
select * from t1;
+-------------------+
| a                 |
+-------------------+
| 98113699159474176 |
| 98113699159474177 |
+-------------------+

See Also

Comments

Comments loading...
Content reproduced on this site is the property of its respective owners, and this content is not reviewed in advance by MariaDB. The views, information and opinions expressed by this content do not necessarily represent those of MariaDB or any other party.