Hi everyone,
Thanks for todays phone call; it was my first time calling in and was informative and helpful. I just wanted to follow up on my question about filtering on string arguments of USDT probes. Thanks to Brendan for suggesting looking into LLVM's builtins (e.g. __builtin_memcmp, __builtin_strstr); my initial experimentation with them has been unsuccessful, but I plan to keep trying. An additional issue brought up on the call (I apologize for forgetting by whom) was that any comparisons on long strings would bloat the program, perhaps beyond the maximum allowed program size. Would the solution to this be to have something like another BPF helper function in the kernel? Something we may end up doing is passing u64 hash of our query string to our probes and filter on it. If anyone has other recommendations for workarounds, I'm all ears. Thanks, Kyle Laracey MemSQL Performance Engineer
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