Use setproctitle_fast() to update the ps status, if available.

FreeBSD has introduced a faster variant of setproctitle().  Use it,
where available.

Author: Thomas Munro
Discussion: https://postgr.es/m/CAEepm=1wKMTi81uodJ=1KbJAz5WedOg=cr8ewEXrUFeaxWEgww@mail.gmail.com

configure

@@ -14916,7 +14916,7 @@ fi
 LIBS_including_readline="$LIBS"
 LIBS=`echo "$LIBS" | sed -e 's/-ledit//g' -e 's/-lreadline//g'`
 
-for ac_func in cbrt clock_gettime dlopen fdatasync getifaddrs getpeerucred getrlimit mbstowcs_l memmove poll posix_fallocate pstat pthread_is_threaded_np readlink setproctitle setsid shm_open symlink sync_file_range utime utimes wcstombs_l
+for ac_func in cbrt clock_gettime dlopen fdatasync getifaddrs getpeerucred getrlimit mbstowcs_l memmove poll posix_fallocate pstat pthread_is_threaded_np readlink setproctitle setproctitle_fast setsid shm_open symlink sync_file_range utime utimes wcstombs_l
 do :
   as_ac_var=`$as_echo "ac_cv_func_$ac_func" | $as_tr_sh`
 ac_fn_c_check_func "$LINENO" "$ac_func" "$as_ac_var"

configure.in

@@ -1540,7 +1540,7 @@ PGAC_FUNC_WCSTOMBS_L
 LIBS_including_readline="$LIBS"
 LIBS=`echo "$LIBS" | sed -e 's/-ledit//g' -e 's/-lreadline//g'`
 
-AC_CHECK_FUNCS([cbrt clock_gettime dlopen fdatasync getifaddrs getpeerucred getrlimit mbstowcs_l memmove poll posix_fallocate pstat pthread_is_threaded_np readlink setproctitle setsid shm_open symlink sync_file_range utime utimes wcstombs_l])
+AC_CHECK_FUNCS([cbrt clock_gettime dlopen fdatasync getifaddrs getpeerucred getrlimit mbstowcs_l memmove poll posix_fallocate pstat pthread_is_threaded_np readlink setproctitle setproctitle_fast setsid shm_open symlink sync_file_range utime utimes wcstombs_l])
 
 AC_REPLACE_FUNCS(fseeko)
 case $host_os in

src/backend/utils/misc/ps_status.c

@@ -38,6 +38,9 @@ bool		update_process_title = true;
 /*
  * Alternative ways of updating ps display:
  *
+ * PS_USE_SETPROCTITLE_FAST
+ *	   use the function setproctitle_fast(const char *, ...)
+ *	   (newer FreeBSD systems)
  * PS_USE_SETPROCTITLE
  *	   use the function setproctitle(const char *, ...)
  *	   (newer BSD systems)
@@ -59,7 +62,9 @@ bool		update_process_title = true;
  *	   don't update ps display
  *	   (This is the default, as it is safest.)
  */
-#if defined(HAVE_SETPROCTITLE)
+#if defined(HAVE_SETPROCTITLE_FAST)
+#define PS_USE_SETPROCTITLE_FAST
+#elif defined(HAVE_SETPROCTITLE)
 #define PS_USE_SETPROCTITLE
 #elif defined(HAVE_PSTAT) && defined(PSTAT_SETCMD)
 #define PS_USE_PSTAT
@@ -286,7 +291,7 @@ init_ps_display(const char *username, const char *dbname,
 	 * Make fixed prefix of ps display.
 	 */
 
-#ifdef PS_USE_SETPROCTITLE
+#if defined(PS_USE_SETPROCTITLE) || defined(PS_USE_SETPROCTITLE_FAST)
 
 	/*
 	 * apparently setproctitle() already adds a `progname:' prefix to the ps
@@ -349,6 +354,8 @@ set_ps_display(const char *activity, bool force)
 
 #ifdef PS_USE_SETPROCTITLE
 	setproctitle("%s", ps_buffer);
+#elif defined(PS_USE_SETPROCTITLE_FAST)
+	setproctitle_fast("%s", ps_buffer);
 #endif
 
 #ifdef PS_USE_PSTAT

src/include/pg_config.h.in

@@ -489,6 +489,9 @@
 /* Define to 1 if you have the `setproctitle' function. */
 #undef HAVE_SETPROCTITLE
 
+/* Define to 1 if you have the `setproctitle_fast' function. */
+#undef HAVE_SETPROCTITLE_FAST
+
 /* Define to 1 if you have the `setsid' function. */
 #undef HAVE_SETSID