UUID_VX component¶

A Universally Unique Identifier (UUID) is a 128-bit number used to identify information uniquely in computer systems. It is often represented as a 32-character hexadecimal string divided into five groups separated by hyphens.

Benefit	Description
Global Uniqueness	UUIDs ensure that each identifier is unique across different databases and systems without needing a central authority to manage the IDs. This prevents ID conflicts when merging data from multiple sources.
Decentralized Generation	Since UUIDs can be generated independently by different systems, there is no need for coordination. This is particularly useful in distributed environments where systems might not have constant communication with each other.
Scalability	UUIDs support scalability in distributed databases. New records can be added without worrying about generating duplicate IDs, even when data is inserted concurrently across multiple nodes.
Improved Data Merging	When data from various sources is combined, UUIDs prevent conflicts, making the merging process simpler and more reliable.
Security	UUIDs, especially those generated randomly (like UUIDv4), are hard to predict, adding a layer of security when used as identifiers.

The following table describes the UUID versions:

UUID Version	Description
Version 1 (Time-based)	- Generated using the current time and a node identifier (usually the MAC address). - Ensures uniqueness over time and across nodes.
Version 2 (DCE Security)	- Similar to version 1 but includes additional information such as POSIX UID/GID. - Often used in environments requiring enhanced security.
Version 3 (Name-based, MD5 hash)	- Generated from a namespace identifier and a name (string). - Uses the MD5 hashing algorithm to ensure the UUID is derived from the namespace and name.
Version 4 (Random)	- Generated using random numbers. - Offers high uniqueness and is easy to generate without requiring specific inputs.
Version 5 (Name-based, SHA-1 hash)	- Similar to version 3 but uses the SHA-1 hashing algorithm. - Provides a stronger hash function than MD5.
Version 6 (Time-ordered)	- A reordered version of UUIDv1 for better indexing and storage efficiency. - Combines timestamp and random or unique data.
Version 7 (Unix Epoch Time)	- Combines a high-precision timestamp with random data. - Provides unique, time-ordered UUIDs that are ideal for database indexing.
Version 8 (Custom)	- Reserved for user-defined purposes and experimental uses. - Allows custom formats and structures according to specific requirements.

UUID version 4 (UUIDv4) generates a unique identifier using random numbers. This randomness ensures a high level of uniqueness without needing a central authority to manage IDs. However, using UUIDv4 as a primary key in a distributed database is not recommended. The random nature of UUIDv4 leads to several issues:

Issue	Description
Inefficient Indexing	UUIDv4 does not follow any order, causing inefficient indexing. Databases struggle to keep records organized, leading to slower query performance.
Fragmentation	The random distribution of UUIDv4 can cause data fragmentation, making database storage less efficient.
Storage Space	UUIDs are larger (128 bits) than traditional integer keys, consuming more storage space and memory.

For better performance and efficiency in a distributed database, consider using UUIDv7, which incorporates timestamps for some order levels.

UUID version 7 (UUIDv7) creates time-ordered identifiers by encoding a Unix timestamp with millisecond precision in the first 48 bits. It uses 6 bits to specify the UUID version and variant, while the remaining 74 bits are random. This time-ordering results in nearly sequential values, which helps improve index performance and locality in distributed systems.

Install the UUID_VX component¶

mysql> INSTALL COMPONENT 'file://component_uuid_vx_udf';

Expected output

Query OK, 0 rows affected (0.03 sec)

Character sets available¶

The following character sets are used in the component:

Character set	Description
ascii	Used everywhere UUID strings are returned by functions or accepted as function arguments.
utf8mb4	Used for string arguments in hash-based UUID generators, like `UUID_V3()` and `UUID_V5()` functions.
binary	Used for arguments in the `BIN_TO_UUID_VX()` function and for results from the `UUID_VX_TO_BIN()` function.

Functions available in UUID_VX¶

The following functions are compatible with all UUID versions:

Function name	Argument	Description
`BIN_TO_UUID_VX()`	One string argument that must be a hexadecimal of exactly 32 characters (16 bytes)	The function returns a UUID with binary data from the argument. It returns an error for all other inputs.
`IS_MAX_UUID_VX()`	One string argument that represents a UUID in standard or hexadecimal form.	The function returns true if the argument is a valid UUID and is a MAX UUID. It returns false for all other inputs. If the argument is NULL, it returns NULL. If the argument cannot be parsed as a UUID, the function throws an error.
`IS_NIL_UUID_VX()`	One string argument representing a UUID in standard or hexadecimal form.	The function returns true if the string is a NIL UUID. If the argument is NULL, it returns NULL. If the argument is not a valid UUID, it throws an error.
`IS_UUID_VX()`	One string argument that represents a UUID in either standard or hexadecimal form.	The function returns true if the argument is a valid UUID. If the argument is NULL, it returns NULL. For any other input, it returns false.
`MAX_UUID_VX()`	No argument	This function generates a MAX UUID, which has all 128 bits set to one (FFFFFFFF-FFFF-FFFF-FFFF-FFFFFFFFFFFF). This function result is the opposite of the NIL UUID.
`NIL_UUID_VX()`	No argument.	This function generates a NIL UUID, which has all 128 bits set to zero (00000000-0000-0000-0000-000000000000).
`UUID_VX_TO_BIN()`	One string argument, formatted as a UUID or in hexadecimal form	The function converts the string arugment to its binary representation.
`UUID_VX_VARIANT()`	One string argument that represents a UUID in either standard or hexadecimal format.	The function returns the UUID version (1-8) or an error if the argument is not a valid UUID or returns NULL if the input is NULL.
`UUID_VX_VERSION()`	One string representing a UUID in standard or hexadecimal form.	The function returns version of UUID(1-8). The function throws an error if the argument is not a valid UUID in formatted or hexadecimal form or returns a NULL if the argument is NULL. If the argument is a valid UUID string but has an unknown value (outside of the 1-8 range) the function returns `-1`.

Examples of functions for all UUID versions¶

mysql> SELECT is_uuid_vx('01900bf6-0eb0-715a-80f4-636367e07777');

Expected output

+----------------------------------------------------+
| is_uuid_vx('01900bf6-0eb0-715a-80f4-636367e07777') |
+----------------------------------------------------+
|                                                  1 |
+----------------------------------------------------+

mysql> SELECT uuid_vx_version('01900bf6-0eb0-715a-80f4-636367e07777');

Expected output

+---------------------------------------------------------+
| uuid_vx_version('01900bf6-0eb0-715a-80f4-636367e07777') |
+---------------------------------------------------------+
|                                                       7 |
+---------------------------------------------------------+

 mysql> SELECT uuid_vx_variant('01900bf6-0eb0-715a-80f4-636367e07777');

Expected output

+---------------------------------------------------------+
| uuid_vx_variant('01900bf6-0eb0-715a-80f4-636367e07777') |
+---------------------------------------------------------+
|                                                       1 |
+---------------------------------------------------------+

UUID generator functions¶

The following functions generate specific UUID versions:

UUID Version	Arguement	Description
`UUID_V1()`	No argument	Generates a version 1 UUID based on a timestamp. If possible, use UUID_V7() instead.
`UUID_V3()`	One or two arguments: the first argument is a string that is hashed with MD5 and used in the UUID; the second argument is optional and specifies a namespace (integer values: DNS: 0, URL: 1, OID: 2, X.500: 3; default is 1 or URL).	Generates a version 3 UUID based on a name. Note: MD5 is outdated and not secure. Use with caution and avoid exposing sensitive data.
`UUID_V4()`	No argument	The function generates a version 4 UUID using random numbers and is similar to the built-in UUID() function.
`UUID_V5()`	One or two arguments: the first argument is a string that is hashed with SHA1 and used in the UUID; the second argument is optional and specifies a namespace (integer values: DNS: 0, URL: 1, OID: 2, X.500: 3; default is 1 or URL).	Generates a version 5 UUID based on a name. Note: SHA1 is better than MD5 but still not secure. Use with caution and avoid exposing sensitive data.
`UUID_V6()`	No argument	Generates a version 6 UUID based on a timestamp. If possible, use UUID_V7() instead.
`UUID_V7()`	Can have either no argument or a one integer argument: the argument is the number of milliseconds to adjust the timestamp forward or backward (negative values).	Generates a version 7 UUID based on a timestamp. If there is no argument, no timestamp shift occurs. Timestamp shift can hide the actual creation time of the record.

The UUID_v3() function and UUID_v5() function do not validate the string argument, such as whether the URL is formatted correctly or the DNS name is correct. These functions generate a string hash and then add that hash to a UUID with the defined namespace. The user specifies the string.

UUID generator examples¶

UUID version 1:

mysql> SELECT uuid_v1();

Expected output

+--------------------------------------+
| uuid_v1()                            |
+--------------------------------------+
| 14c22f93-2962-11ef-9078-c3abf1c446bb |
+--------------------------------------+

UUID version 3 takes one argument and uses the default UUID namespace as “URL”.

mysql> SELECT uuid_v3('http://example.com');

Expected output

+--------------------------------------+
| uuid_v3('http://example.com')        |
+--------------------------------------+
| d632b50c-7913-3137-ae9a-2d93f56e70d5 |
+--------------------------------------+

UUID version 3 takes one argument and uses an explicit UUID namespace is “URL”.

mysql> SELECT uuid_v3('http://example.com', 1);

Expected output

+--------------------------------------+
| uuid_v3('http://example.com')        |
+--------------------------------------+
| d632b50c-7913-3137-ae9a-2d93f56e70d5 |
+--------------------------------------+

UUID version 3 takes one argument, with the explicit UUID namespace set to “DNS”.

mysql> SELECT uuid_v3('example.com',0);

Expected output

+--------------------------------------+
| uuid_v3('example.com',0)             |
+--------------------------------------+
| 9073926b-929f-31c2-abc9-fad77ae3e8eb |
+--------------------------------------+

UUID version 4:

mysql> SELECT uuid_v4();

Expected output

+--------------------------------------+
| uuid_v4()                            |
+--------------------------------------+
| a408e4ad-9b98-4edb-a105-40f22648a928 |
+--------------------------------------+

UUID version 5:

mysql> SELECT uuid_v5("http://example.com");

Expected output

+--------------------------------------+
| uuid_v5("http://example.com")        |
+--------------------------------------+
| 8c9ddcb0-8084-5a7f-a988-1095ab18b5df |
+--------------------------------------+

UUID version 6:

mysql> SELECT uuid_v6();

Expected output

+--------------------------------------+
| uuid_v6()                            |
+--------------------------------------+
| 1ef29686-2168-64a7-b9a2-adb13f80f118 |
+--------------------------------------+

UUID version 7 generation:

mysql>SELECT uuid_v7();

Expected output

+--------------------------------------+
| uuid_v7()                            |
+--------------------------------------+
| 019010f6-0426-70f0-80b0-b63decd3d7d1 |
+--------------------------------------+
1 row in set (0.00 sec)

UUID version 7 with timestamp offset in 84000 seconds in the future

mysql> SELECT uuid_v7(84000000);

Expected output

+--------------------------------------+
| uuid_v7(84000000)                    |
+--------------------------------------+
| 019015f8-c7c4-70b4-8043-fe241c2be36c |
+--------------------------------------+

Time-based functions¶

The following functions are used only with time-based UUIDs, specifically versions 1, 6, and 7.

Function name	Argument	Description
UUID_VX_TO_TIMESTAMP()	One string argument	Returns a timestamp string like “2024-05-29 18:04:14.201”. If the argument is not parsable as UUID v.1,6,7, the function throws an error. The function always uses UTC time, regardless of system settings or time zone settings in MySQL.
UUID_VX_TO_TIMESTAMP_TZ()	One string argument	Returns a timestamp string with the time zone like “Wed May 29 18:05:07 2024 GMT”. If the argument is not parsable as UUID v.1,6,7, the function throws an error. The function always uses UTC time (GMT time zone), regardless of system settings or time zone settings in MySQL.
UUID_VX_TO_UNIXTIME()	One string argument	Returns a number of milliseconds since the Epoch. If the argument is not parsable as UUID v.1,6,7, the function throws an error.

Timestamp-based function examples¶

mysql> SELECT uuid_vx_to_timestamp('01900bf6-0eb0-715a-80f4-636367e07777');

Expected output

+--------------------------------------------------------------+
| uuid_vx_to_timestamp('01900bf6-0eb0-715a-80f4-636367e07777') |
+--------------------------------------------------------------+
| 2024-06-12 10:19:53.392                                      |
+--------------------------------------------------------------+
1 row in set (0.00 sec)

mysql> SELECT uuid_vx_to_timestamp_tz('01900bf6-0eb0-715a-80f4-636367e07777');

Expected output

+-----------------------------------------------------------------+
| uuid_vx_to_timestamp_tz('01900bf6-0eb0-715a-80f4-636367e07777') |
+-----------------------------------------------------------------+
| Wed Jun 12 10:19:53 2024 GMT                                    |
+-----------------------------------------------------------------+

mysql> SELECT uuid_vx_to_unixtime('01900bf6-0eb0-715a-80f4-636367e07777');

Expected output

+-------------------------------------------------------------+
| uuid_vx_to_unixtime('01900bf6-0eb0-715a-80f4-636367e07777') |
+-------------------------------------------------------------+
|                                               1718187593392 |
+-------------------------------------------------------------+

Uninstall the UUID_VX component¶

mysql> UNINSTALL COMPONENT 'file://component_uuid_vx_udf';

Expected output

Query OK, 0 rows affected (0.03 sec)

Get expert help¶

If you need assistance, visit the community forum for comprehensive and free database knowledge, or contact our Percona Database Experts for professional support and services.

Community Forum Get a Percona Expert

Last update: 2024-10-08