Repair an error introduced by log_line_prefix patch: it is not acceptable

to assume that the string pointer passed to set_ps_display is good forever.
There's no need to anyway since ps_status.c itself saves the string, and
we already had an API (get_ps_display) to return it.
I believe this explains Jim Nasby's report of intermittent crashes in
elog.c when %i format code is in use in log_line_prefix.
While at it, repair a previously unnoticed problem: on some platforms such as
Darwin, the string returned by get_ps_display was blank-padded to the maximum
length, meaning that lock.c's attempt to append " waiting" to it never worked.

1 files changed, 12 insertions, 4 deletions

diff --git a/src/backend/utils/error/elog.c b/src/backend/utils/error/elog.c
index c919f7c2c65..358bd982b34 100644
--- a/src/backend/utils/error/elog.c
+++ b/src/backend/utils/error/elog.c
@@ -42,7 +42,7 @@
  *
  *
  * IDENTIFICATION
- *	  $PostgreSQL: pgsql/src/backend/utils/error/elog.c,v 1.155.4.3 2005/10/14 16:41:13 tgl Exp $
+ *	  $PostgreSQL: pgsql/src/backend/utils/error/elog.c,v 1.155.4.4 2005/11/05 03:05:05 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -67,6 +67,7 @@
 #include "tcop/tcopprot.h"
 #include "utils/memutils.h"
 #include "utils/guc.h"
+#include "utils/ps_status.h"
 
 
 /* Global variables */
@@ -1461,13 +1462,20 @@ log_line_prefix(StringInfo buf)
 				break;
 			case 'i':
 				if (MyProcPort)
-					appendStringInfo(buf, "%s", MyProcPort->commandTag);
+				{
+					const char *psdisp;
+					int		displen;
+
+					psdisp = get_ps_display(&displen);
+					appendStringInfo(buf, "%.*s", displen, psdisp);
+				}
 				break;
 			case 'r':
-				if (MyProcPort)
+				if (MyProcPort && MyProcPort->remote_host)
 				{
 					appendStringInfo(buf, "%s", MyProcPort->remote_host);
-					if (strlen(MyProcPort->remote_port) > 0)
+					if (MyProcPort->remote_port &&
+						MyProcPort->remote_port[0] != '\0')
 						appendStringInfo(buf, "(%s)",
 										 MyProcPort->remote_port);
 				}