Any side-effects/implications of changing time_zone config in MySQL from SYSTEM to +00:00?

MySQL & MariaDB Percona Server for MySQL 8.0
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Hi Folks,

We have a date time column defined as datetime(6) NOT NULL DEFAULT CURRENT_TIMESTAMP(6) ON UPDATE CURRENT_TIMESTAMP(6).

We use UTC on our machines. We found that changing the value of @@session.time_zone from SYSTEM to +00:00 reduced kernel calls and gave better performance in use cases that do lot of inserts/updates.

In both cases (ie +00:00 or SYSTEM) it should be using UTC time zone, right? Are there any side-effects/implications of changing the value from SYSTEM to +00:00 that I need to be aware of?

We are thinking of changing @@global.time_zone as well to +00:00.

Thanks,
Vamsi

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Hello @Vamsi_P,
If your system/OS timezone is currently UTC, changing MySQL to +00:00 should be the same thing as UTC. Very interesting that this saves resources. I guess because using SYSTEM causes MySQL to make a request to the OS vs just calculating itself.

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ok, thank you!
Vamsi

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I know I’m late to the party, but this forum topic was third in a google search for mysql time zone system calls; The issue is possibly related to 1244585 – Reduce lock contention in __tz_convert()
There was a good article here MySQL time_zone and CPU Spike another performance troubleshooting

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