Code review for log_line_prefix patch. Cooperate with StringInfo instead

of fighting it, avoid hard-wired (and wrong) assumption about max length
of prefix, cause %l to actually work as documented, don't compute data
we may not need.

src/backend/utils/misc/ps_status.c

@@ -5,7 +5,7 @@
  * to contain some useful information. Mechanism differs wildly across
  * platforms.
  *
- * $PostgreSQL: pgsql/src/backend/utils/misc/ps_status.c,v 1.18 2004/03/09 04:43:07 momjian Exp $
+ * $PostgreSQL: pgsql/src/backend/utils/misc/ps_status.c,v 1.19 2004/03/19 02:23:59 tgl Exp $
  *
  * Copyright (c) 2000-2003, PostgreSQL Global Development Group
  * various details abducted from various places
@@ -277,15 +277,14 @@ init_ps_display(const char *username, const char *dbname,
 void
 set_ps_display(const char *activity)
 {
-	/* no ps display for stand-alone backend */
-	if (!IsUnderPostmaster)
-		return;
-
-	/* save it for logging context */
+	/* save tag for possible use by elog.c */
 	if (MyProcPort)
-		MyProcPort->commandTag = (char *) activity;
+		MyProcPort->commandTag = activity;
 
 #ifndef PS_USE_NONE
+	/* no ps display for stand-alone backend */
+	if (!IsUnderPostmaster)
+		return;
 
 #ifdef PS_USE_CLOBBER_ARGV
 	/* If ps_buffer is a pointer, it might still be null */

src/include/libpq/libpq-be.h

@@ -11,7 +11,7 @@
  * Portions Copyright (c) 1996-2003, PostgreSQL Global Development Group
  * Portions Copyright (c) 1994, Regents of the University of California
  *
- * $PostgreSQL: pgsql/src/include/libpq/libpq-be.h,v 1.42 2004/03/09 04:43:07 momjian Exp $
+ * $PostgreSQL: pgsql/src/include/libpq/libpq-be.h,v 1.43 2004/03/19 02:23:59 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -50,8 +50,6 @@ typedef struct Port
 	SockAddr	raddr;			/* remote addr (client) */
 	char        *remote_host;   /* name (or ip addr) of remote host */
 	char        *remote_port;   /* text rep of remote port */
-	char        *commandTag;    /* command tag for display in log lines */
-	struct timeval  session_start;  /* for session duration logging */
 	CAC_state	canAcceptConnections;	/* postmaster connection status */
 
 	/*
@@ -73,6 +71,14 @@ typedef struct Port
 	char		md5Salt[4];		/* Password salt */
 	char		cryptSalt[2];	/* Password salt */
 
+	/*
+	 * Information that really has no business at all being in struct Port,
+	 * but since it gets used by elog.c in the same way as database_name
+	 * and other members of this struct, we may as well keep it here.
+	 */
+	const char *commandTag;			/* current command tag */
+	struct timeval session_start;	/* for session duration logging */
+
 	/*
 	 * SSL structures
 	 */