XOR process PID into a backend's initial random seed, to ensure that

different backends get a reasonably wide set of initial seeds even if
gettimeofday returns tv_usec values with only a few bits of precision.
Per recent discussion.
This commit is contained in:
Tom Lane 2004-10-07 00:03:15 +00:00
parent f629583f94
commit 52a45818a1

View File

@ -37,7 +37,7 @@
*
*
* IDENTIFICATION
* $PostgreSQL: pgsql/src/backend/postmaster/postmaster.c,v 1.426 2004/10/06 09:35:21 momjian Exp $
* $PostgreSQL: pgsql/src/backend/postmaster/postmaster.c,v 1.427 2004/10/07 00:03:15 tgl Exp $
*
* NOTES
*
@ -2575,8 +2575,6 @@ static int
BackendRun(Port *port)
{
int status;
struct timeval now;
struct timezone tz;
char remote_host[NI_MAXHOST];
char remote_port[NI_MAXSERV];
char remote_ps_data[NI_MAXHOST];
@ -2754,9 +2752,7 @@ BackendRun(Port *port)
* start a new random sequence in the random() library function.
*/
random_seed = 0;
gettimeofday(&now, &tz);
srandom((unsigned int) now.tv_usec);
srandom((unsigned int) (MyProcPid ^ port->session_start.tv_usec));
/* ----------------
* Now, build the argv vector that will be given to PostgresMain.