Add comment about rationale for continuing to use C library functions

instead of src/timezone for timestamping log entries.

src/backend/utils/error/elog.c

@@ -37,7 +37,7 @@
  *
  *
  * IDENTIFICATION
- *	  $PostgreSQL: pgsql/src/backend/utils/error/elog.c,v 1.140 2004/06/03 02:08:04 tgl Exp $
+ *	  $PostgreSQL: pgsql/src/backend/utils/error/elog.c,v 1.141 2004/06/21 14:12:38 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -1214,6 +1214,16 @@ log_line_prefix(StringInfo buf)
 				break;
 			case 't':
 				{
+					/*
+					 * Note: for %t and %s we deliberately use the C library's
+					 * strftime/localtime, and not the equivalent functions
+					 * from src/timezone.  This ensures that all backends
+					 * will report log entries in the same timezone, namely
+					 * whatever C-library setting they inherit from the
+					 * postmaster.  If we used src/timezone then local
+					 * settings of the TimeZone GUC variable would confuse
+					 * the log.
+					 */
 					time_t stamp_time = time(NULL);
 					char strfbuf[128];