Re: client_connection_check_interval default value

Hi Fujii,

Thanks for the patch. The rate-limiting approach makes sense to me. A couple of thoughts:

1) I think Chao Li's suggestion of using max(10s, deadlock_timeout) as the rate limit interval is worth adopting. If someone has set deadlock_timeout to, say, 30s or 60s, they've already signaled they don't need frequent lock-wait feedback. Logging every 10s after a 60s deadlock_timeout feels inconsistent with that intent.

2) The hardcoded 10s constant — could we define it as a named constant in a header file? That way it's easier to find and reason about if it ever needs to change.

3) Would it make sense to add a regression test for this? Something that verifies the rate limiting actually suppresses the repeated messages at the expected interval.

Regards,