I did some research few weeks ago on the topic of database lookup timing side-channels, conclusion is: They don't really exist (for SELECT FROM WHERE commands atleast). https://altayakkus.substack.com/p/timing-side-channel-on-sql...

I came to the same conclusion. Many string comparison implementations don't actually compare one character at a time. In one case strcmp seemed to compare eight characters at a time, so you would need to guess eight characters correctly to get a time difference. Glibc memcmp can compare 32 bytes at a time. In C# the timing of string compare depends on whether it does Unicode normalization or not. Even then, the difference is less than a nanosecond per compared character. It is not as straightforward that every string comparison between sensitive data and user input is at risk of timing attacks.

https://www.sjoerdlangkemper.nl/2024/05/29/string-comparison...