Make log_temp_files based on kB, and revert docs & comments to match.

Per extensive discussion on pgsql-hackers.  We are deliberately not
back-patching this even though the behavior of 8.3 and 8.4 is
unquestionably broken, for fear of breaking existing users of this
parameter.  This incompatibility should be release-noted.

doc/src/sgml/config.sgml

-<!-- $PostgreSQL: pgsql/doc/src/sgml/config.sgml,v 1.292 2010/07/06 21:14:25 rhaas Exp $ -->
+<!-- $PostgreSQL: pgsql/doc/src/sgml/config.sgml,v 1.293 2010/07/06 22:55:26 rhaas Exp $ -->
 
 <chapter Id="runtime-config">
   <title>Server Configuration</title>
@@ -3607,7 +3607,7 @@ FROM pg_stat_activity;
         A log entry is made for each temporary file when it is deleted.
         A value of zero logs all temporary file information, while positive
         values log only files whose size is greater than or equal to
-        the specified number of bytes.  The
+        the specified number of kilobytes.  The
         default setting is <literal>-1</>, which disables such logging.
         Only superusers can change this setting.
        </para>

src/backend/storage/file/fd.c

@@ -7,7 +7,7 @@
  * Portions Copyright (c) 1994, Regents of the University of California
  *
  * IDENTIFICATION
- *	  $PostgreSQL: pgsql/src/backend/storage/file/fd.c,v 1.156 2010/02/26 02:00:59 momjian Exp $
+ *	  $PostgreSQL: pgsql/src/backend/storage/file/fd.c,v 1.157 2010/07/06 22:55:26 rhaas Exp $
  *
  * NOTES:
  *
@@ -1062,7 +1062,7 @@ FileClose(File file)
 		{
 			if (stat(vfdP->fileName, &filestats) == 0)
 			{
-				if (filestats.st_size >= log_temp_files)
+				if ((filestats.st_size / 1024) >= log_temp_files)
 					ereport(LOG,
 							(errmsg("temporary file: path \"%s\", size %lu",
 									vfdP->fileName,

src/backend/utils/misc/guc.c

@@ -10,7 +10,7 @@
  * Written by Peter Eisentraut <peter_e@gmx.net>.
  *
  * IDENTIFICATION
- *	  $PostgreSQL: pgsql/src/backend/utils/misc/guc.c,v 1.560 2010/07/06 19:18:58 momjian Exp $
+ *	  $PostgreSQL: pgsql/src/backend/utils/misc/guc.c,v 1.561 2010/07/06 22:55:26 rhaas Exp $
  *
  *--------------------------------------------------------------------
  */
@@ -2061,7 +2061,7 @@ static struct config_int ConfigureNamesInt[] =
 
 	{
 		{"log_temp_files", PGC_SUSET, LOGGING_WHAT,
-			gettext_noop("Log the use of temporary files larger than this number of bytes."),
+			gettext_noop("Log the use of temporary files larger than this number of kilobytes."),
 			gettext_noop("Zero logs all files. The default is -1 (turning this feature off)."),
 			GUC_UNIT_KB
 		},