# Agenda for XALT Monthly Mtg August 15, 2024 10:00 US Central (14:00 UTC)
- Q/A
- Discussion of UUID V7
- version 7 is like this: 019152cb-a8da-79c3-bd43-481b12d9b1a2
- Upper 12 bytes are time-date encoded
- There is a 7 at the 13th character
- The rest are random. Computed by getentropy() in modern libc (2017+)
- where 12 symbols (019152cb-a8da) are an encoded date string
- Example of 6 UUID V7 generated on one node (multi-core) in test code with mpi program.

019152ce-4ae6-7107-abf6-d1d69e71836f
019152ce-4ae6-72a5-b0b5-0aeca0ac95bb
019152ce-4ae6-741d-8630-b8ecb46a7749
019152ce-4ae6-7463-a357-a9e62916bbe4
019152ce-4ae6-7533-a129-6816627aa851
019152ce-4ae6-7880-a09e-2b46d2cb5d9e

- This allows for better MySQL DB performance
- XALT uses UUID's to connect runs to links, libraries to runs etc.
- Current UUID's are completely arbitrary (version 4). These uuids shown below were generated one after the other. Note the "4" in the 13th character.

41ed2dd2-919f-4adf-aa88-58625c34ef54
10a6ba99-c821-4e85-bb74-6c4c4963f013
ba33be5a-de9a-448d-84b7-832c3c1c1edc
cfefd438-663e-462d-9a9e-a02531321611
f353841b-e083-47f9-89ed-52de34a92bb4
9cab3afb-0964-4f31-92e2-090d52843138

- Therefore much harder for DB to find
- This is now available on the testing branch
- Testing of UUID v7
- Tested running on same node multi-core
- Tested running on different nodes
- No repeats!!!!
- This will be named either XALT 3.1 or XALT 4.0 when released
- XALT will use UUID v7 when getentropy() routine is available.
- Otherwise it will use UUID v4.
- At TACC all machines will use UUID v7.
- Except for Frontera currently
- Frontera will be upgraded to Rocky 9 and will support UUID v7 then.
- ## Next Meeting Sept 26 at 10:00 am US Central (14:00 UTC)