From aolserver/nsd/log.c:
Log(Ns_LogSeverity severity, char *fmt, va_list *argsPtr)
. . .
fprintf(fp, "%s[%d.%d][%s] %s: ", timebuf,
Ns_InfoPid(), Ns_ThreadId(), Ns_ThreadGetName(), severityStr);
The
third field is the thread id. The fourth is more
functional. For connections it will be the connection number, but it
can be all sorts of things, including
-main-,
-sched-,
-socks-, and
-thread<n>-.