diff -rpcd a/src/backend/utils/error/elog.c b/src/backend/utils/error/elog.c
*** a/src/backend/utils/error/elog.c	2013-06-25 03:55:41.000000000 +0900
--- b/src/backend/utils/error/elog.c	2013-09-09 15:56:28.000000000 +0900
*************** static void log_line_prefix(StringInfo b
*** 170,175 ****
--- 170,176 ----
  static void send_message_to_server_log(ErrorData *edata);
  static void send_message_to_frontend(ErrorData *edata);
  static char *expand_fmt_string(const char *fmt, ErrorData *edata);
+ static const char *get_errno_symbol(int errnum);
  static const char *useful_strerror(int errnum);
  static const char *error_severity(int elevel);
  static void append_with_tabs(StringInfo buf, const char *str);
*************** expand_fmt_string(const char *fmt, Error
*** 2921,2933 ****
  }
  
  
  /*
   * A slightly cleaned-up version of strerror()
   */
  static const char *
  useful_strerror(int errnum)
  {
! 	/* this buffer is only used if errno has a bogus value */
  	static char errorstr_buf[48];
  	const char *str;
  
--- 2922,3080 ----
  }
  
  
+ static const struct
+ {
+ 	int			errnum;
+ 	char	   *symbol;
+ }	errno_symbols[] =
+ 
+ {
+ 	{
+ 		EINVAL, "EINVAL"
+ 	},
+ 	{
+ 		ENOENT, "ENOENT"
+ 	},
+ 	{
+ 		EMFILE, "EMFILE"
+ 	},
+ 	{
+ 		EACCES, "EACCES"
+ 	},
+ 	{
+ 		EBADF, "EBADF"
+ 	},
+ 	{
+ 		ENOMEM, "ENOMEM"
+ 	},
+ 	{
+ 		E2BIG, "E2BIG"
+ 	},
+ 	{
+ 		ENOEXEC, "ENOEXEC"
+ 	},
+ 	{
+ 		EXDEV, "EXDEV"
+ 	},
+ 	{
+ 		EEXIST, "EEXIST"
+ 	},
+ 	{
+ 		EPIPE, "EPIPE"
+ 	},
+ 	{
+ 		ENOSPC, "ENOSPC"
+ 	},
+ 	{
+ 		ECHILD, "ECHILD"
+ 	},
+ 	{
+ 		ENOTEMPTY, "ENOTEMPTY"
+ 	},
+ 	{
+ 		EAFNOSUPPORT, "EAFNOSUPPORT"
+ 	},
+ 	{
+ 		ECONNREFUSED, "ECONNREFUSED"
+ 	},
+ 	{
+ 		EDEADLK, "EDEADLK"
+ 	},
+ 	{
+ 		EDOM, "EDOM"
+ 	},
+ 	{
+ 		EIDRM, "EIDRM"
+ 	},
+ 	{
+ 		EINTR, "EINTR"
+ 	},
+ 	{
+ 		EIO, "EIO"
+ 	},
+ 	{
+ 		EISDIR, "EISDIR"
+ 	},
+ 	{
+ 		EMSGSIZE, "EMSGSIZE"
+ 	},
+ 	{
+ 		ENFILE, "ENFILE"
+ 	},
+ 	{
+ 		ENOBUFS, "ENOBUFS"
+ 	},
+ 	{
+ 		ENOSYS, "ENOSYS"
+ 	},
+ 	{
+ 		ENOTDIR, "ENOTDIR"
+ 	},
+ 	{
+ 		EOPNOTSUPP, "EOPNOTSUPP"
+ 	},
+ 	{
+ 		EPERM, "EPERM"
+ 	},
+ 	{
+ 		EPROTONOSUPPORT, "EPROTONOSUPPORT"
+ 	},
+ 	{
+ 		ERANGE, "ERANGE"
+ 	},
+ 	{
+ 		ESRCH, "ESRCH"
+ 	},
+ #ifdef ECONNRESET
+ 	{
+ 		ECONNRESET, "ECONNRESET"
+ 	},
+ #endif
+ #ifdef EINPROGRESS
+ 	{
+ 		EINPROGRESS, "EINPROGRESS"
+ 	},
+ #endif
+ #ifdef EROFS
+ 	{
+ 		EROFS, "EROFS"
+ 	},
+ #endif
+ #ifdef EAGAIN
+ 	{
+ 		EAGAIN, "EAGAIN"
+ 	},
+ #endif
+ #if defined(EWOULDBLOCK) && (!defined(EAGAIN) || (EWOULDBLOCK != EAGAIN))
+ 	{
+ 		EWOULDBLOCK, "EWOULDBLOCK"
+ 	}
+ #endif
+ };
+ 
+ /*
+  * Returns a symbol (e.g. ENOENT) for an errno value.
+  * Returns NULL if no corresponding symbol is found.
+  */
+ static const char *
+ get_errno_symbol(int errnum)
+ {
+ 	int			i;
+ 
+ 	for (i = 0; i < lengthof(errno_symbols); i++)
+ 		if (errno_symbols[i].errnum == errnum)
+ 			return errno_symbols[i].symbol;
+ 
+ 	return NULL;
+ }
+ 
  /*
   * A slightly cleaned-up version of strerror()
   */
  static const char *
  useful_strerror(int errnum)
  {
! 	/* this buffer is only used if strerror() fails to return a useful string */
  	static char errorstr_buf[48];
  	const char *str;
  
*************** useful_strerror(int errnum)
*** 2940,2948 ****
  
  	/*
  	 * Some strerror()s return an empty string for out-of-range errno. This is
! 	 * ANSI C spec compliant, but not exactly useful.
  	 */
! 	if (str == NULL || *str == '\0')
  	{
  		snprintf(errorstr_buf, sizeof(errorstr_buf),
  		/*------
--- 3087,3099 ----
  
  	/*
  	 * Some strerror()s return an empty string for out-of-range errno. This is
! 	 * ANSI C spec compliant, but not exactly useful. glibc's strerror()
! 	 * returns "???" if it cannot transcode a message to the codeset specified
! 	 * by LC_CTYPE.
  	 */
! 	if (str == NULL || *str == '\0' || *str == '?')
! 		str = get_errno_symbol(errnum);
! 	if (str == NULL)
  	{
  		snprintf(errorstr_buf, sizeof(errorstr_buf),
  		/*------