Do msgs mixed with each other when many clients call log_error at the same time?

[shangshujie365]

Hi, are you still working on this project?
I have a question, if many client call 'select log_error' at the same time, will the msg wrote to error file be mixed with each other? Because many threads write a single file at the same time.
If so, How to solve this problem? Do we need a lock to protect data before we write msg out?

[federico-razzoli]

I'm no developer, but here's my understanding:

• A single sprintf() call is thread safe, as required by POSIX. So a line should never be corrupted.
• Multiple sprintf() calls from multiple threads can be reorder, so never try to call this UDF to print consecutive lines.