Bug #103196 | Reading GLOBAL variables without locking | ||
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Submitted: | 2 Apr 2021 15:24 | Modified: | 6 Apr 2021 9:37 |
Reporter: | Luis Donoso | Email Updates: | |
Status: | Not a Bug | Impact on me: | |
Category: | MySQL Server | Severity: | S3 (Non-critical) |
Version: | OS: | Any | |
Assigned to: | CPU Architecture: | Any |
[2 Apr 2021 15:24]
Luis Donoso
[5 Apr 2021 13:19]
MySQL Verification Team
Hi Mr. Donoso, Thank you for your bug report. However, this is not a bug. On all architectures that we support, this operation is atomic, for all 64-big integers. This is a reason why we have a proper casting in all such places. Not a bug.
[6 Apr 2021 9:37]
Luis Donoso
Please, I kindly request the status to be open. There is another problem related with no using barriers. As there are no barriers controlling the access to the variable, the compiler assumes just one thread access to the variable and can apply optimizations like do not read the value from the RAM if the value is already in the cache which would cause some threads may use a stale value of the variable. Please, find more info about this problem in https://stackoverflow.com/a/1351902