On Sat, Oct 13, 2018 at 11:45:17PM +1300, Thomas Munro wrote: > + /* Set a different seed for random() in every backend. */ > + srandom((unsigned int) MyProcPid ^ (unsigned int) MyStartTimestamp);
> - TimestampDifference(0, port->SessionStartTime, &secs, &usecs); > - srandom((unsigned int) (MyProcPid ^ (usecs << 12) ^ secs)); Compared to the old code, the new code requires more wall time to visit every possible seed value. New code xor's the PID bits into the fastest-changing timestamp bits, so only about twenty bits can vary within any given one-second period. (That assumes a PID space of twenty or fewer bits; fifteen bits is the Linux default.) Is that aspect of the change justified?
