MDEV-33710 Implement UUID_TIMESTAMP() function #4496

varundeepsaini · 2025-12-23T19:21:46Z

The Jira issue number for this PR is: MDEV-33710

Description

Adds UUID_TIMESTAMP(uuid) function to extract timestamps from UUIDv1 and UUIDv7 values. Returns NULL for other versions (e.g., v4) or invalid input.

Release Notes

New function: UUID_TIMESTAMP(uuid) - Returns the generation timestamp from UUIDv1/v7 as TIMESTAMP(6).

How can this PR be tested?

./mysql-test/mtr --suite=type_uuid func_uuid_timestamp

Basing the PR against the correct MariaDB version

This is a new feature and the PR is based against the main branch.
This is a bug fix.

PR quality check

I checked the CODING_STANDARDS.md file and my PR conforms to this where appropriate.
For any trivial modifications to the PR, I am ok with the reviewer making the changes themselves.

…v1 and UUIDv7 values

plugin/type_uuid/mysql-test/type_uuid/func_uuid_timestamp.test

plugin/type_uuid/item_uuidfunc.cc

plugin/type_uuid/item_uuidfunc.h

plugin/type_uuid/item_uuidfunc.cc

FooBarrior · 2025-12-24T20:16:40Z

I have some concern about the tests... it's not easy to validate the UUID values used there.
One approach I can think of is:

set timestamp to a fixed value. This will affect NOW() output
See that value returned by UUID_TIMESTAMP(UUID*()) matches our value

We can test a couple of random values, plus corner cases: min and max value for timestamp variable, and for UUID

FooBarrior · 2025-12-24T21:27:29Z

Strangely, there is a different result outpoutted in amd64-debian-11-debug-ps-embedded test run:

--- /home/buildbot/amd64-debian-11-debug-ps-embedded/build/plugin/type_uuid/mysql-test/type_uuid/func_uuid_timestamp.result	2025-12-23 19:37:10.000000000 +0000
+++ /home/buildbot/amd64-debian-11-debug-ps-embedded/build/plugin/type_uuid/mysql-test/type_uuid/func_uuid_timestamp.reject	2025-12-23 19:42:40.539670984 +0000
@@ -1,9 +1,9 @@
 SELECT UUID_TIMESTAMP('018d17f3-e9a3-7000-8000-000000000000');
 UUID_TIMESTAMP('018d17f3-e9a3-7000-8000-000000000000')
-2024-01-17 20:34:37.539000
+2024-01-17 15:04:37.539000
 SELECT UUID_TIMESTAMP('0188b5b8-8000-7000-8000-000000000000');
 UUID_TIMESTAMP('0188b5b8-8000-7000-8000-000000000000')
-2023-06-13 22:35:47.520000
+2023-06-13 17:05:47.520000

Please take a look

varundeepsaini · 2025-12-25T15:13:45Z

i think the test failing is a timezone issue (exact 5.30 HRS), ill fix that

FooBarrior

Thank you @varundeepsaini for the update, and besides such aquick one!
The PR moves in the right direction. Still some work to be done.

mysys/my_uuid.c

plugin/type_uuid/mysql-test/type_uuid/func_uuid_timestamp.result

plugin/type_uuid/item_uuidfunc.cc

FooBarrior · 2025-12-25T18:55:31Z

plugin/type_uuid/item_uuidfunc.cc

+
+  my_time_t seconds;
+  ulong usec;
+  const uchar *buf= (const uchar *) uuid.to_lex_cstring().str;


No functions really need uchar (except the newly added one, which we can change), also uuid is natively stored in char, so why make a conversion?

the mi_ prefix functions use uchar (they do cast it themselves tho, i can remove it from here but again, the cast is still there)

what do you mean? where??

https://github.com/varundeepsaini/server/blob/32e6f8ff2eb54f029e9fced9b17b780e7b7bd6d9/include/myisampack.h#L47-L51

plugin/type_uuid/mysql-test/type_uuid/func_uuid_timestamp.test

mysys/my_uuid.c

FooBarrior · 2025-12-25T19:03:23Z

mysys/my_uuid.c

+    Bytes 6-7:  version (4 bits) + sub-millisecond precision (12 bits)
+*/
+
+my_bool my_uuid_extract_ts(const uchar *uuid, my_time_t *seconds, ulong *usec)


Let's use just int.
Or alternatively, bool, with true meaning success

We might as well use bool here since there are only two result types.

Note for both int and bool: I hear that the convention is 1/true = error (which one might consider “timestamp invalid” to be one) and 0/false = no error.

plugin/type_uuid/item_uuidfunc.cc

FooBarrior · 2025-12-25T19:06:44Z

Never mind the failing appveyor, it is used to be failing. However it may be useful to check the results, as it can reveal some windows build quirks (for example msvc doesn't like bool vs int mismatch, and has a 32-bit long )

plugin/type_uuid/mysql-test/type_uuid/func_uuid_timestamp.test

ParadoxV5

just passing by

ParadoxV5 · 2025-12-28T03:26:49Z

mysys/my_uuid.c

+    return 1;
+  }
+
+  if (version == 1)
+  {


Beginner question: Would a switch block work here?

ParadoxV5 · 2025-12-28T03:31:03Z

mysys/my_uuid.c

+    Bytes 6-7:  version (4 bits) + sub-millisecond precision (12 bits)
+*/
+
+my_bool my_uuid_extract_ts(const uchar *uuid, my_time_t *seconds, ulong *usec)


We might as well use bool here since there are only two result types.

Note for both int and bool: I hear that the convention is 1/true = error (which one might consider “timestamp invalid” to be one) and 0/false = no error.

Resolved

varundeepsaini · 2025-12-29T13:31:28Z

@FooBarrior the my_uuic.c file is being compiled as c

hence when trying to use bool

it is triggering this macro

should i switch to int / my_bool ?

#if !defined(__cplusplus) && !defined(bool)
#define bool In_C_you_should_use_my_bool_instead()
#endif```

plugin/type_uuid/mysql-test/type_uuid/func_uuid_timestamp.test

mysys/my_uuid.c

Signed-off-by: Varun Deep Saini <varun.23bcs10048@ms.sst.scaler.com>

varundeepsaini · 2025-12-31T04:49:59Z

Generated the UUIDs from https://www.uuidgenerator.net/
and the min max UUIDs by hand

mysys/my_uuid.c

Signed-off-by: Varun Deep Saini <varun.23bcs10048@ms.sst.scaler.com>

Implement UUID_TIMESTAMP() function that extracts timestamp from UUID…

9aa596f

…v1 and UUIDv7 values

varundeepsaini force-pushed the MDEV-33710-uuid-timestamp branch from 5bbed91 to 9aa596f Compare December 23, 2025 19:33

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refactoring

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refactoring

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fixed test

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varundeepsaini requested a review from FooBarrior December 26, 2025 17:08

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refactored if to switch

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varundeepsaini requested a review from ParadoxV5 December 28, 2025 05:31

changed return type to bool

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gkodinov added the External Contribution All PRs from entities outside of MariaDB Foundation, Corporation, Codership agreements. label Dec 29, 2025

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varundeepsaini requested a review from FooBarrior December 31, 2025 04:50

varundeepsaini force-pushed the MDEV-33710-uuid-timestamp branch from d5dd95d to acd4413 Compare December 31, 2025 14:09

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Signed-off-by: Varun Deep Saini <varun.23bcs10048@ms.sst.scaler.com>

varundeepsaini force-pushed the MDEV-33710-uuid-timestamp branch from acd4413 to 879c14c Compare January 19, 2026 19:15

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MDEV-33710 Implement UUID_TIMESTAMP() function #4496

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MDEV-33710 Implement UUID_TIMESTAMP() function #4496

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varundeepsaini commented Dec 23, 2025

Description

Release Notes

How can this PR be tested?

Basing the PR against the correct MariaDB version

PR quality check

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FooBarrior commented Dec 24, 2025

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