diff -rpcd orig/src/backend/postmaster/pgstat.c new/src/backend/postmaster/pgstat.c
*** orig/src/backend/postmaster/pgstat.c	2013-06-25 03:55:41.000000000 +0900
--- new/src/backend/postmaster/pgstat.c	2013-07-08 16:32:44.000000000 +0900
*************** done:
*** 4121,4127 ****
   */
  static bool
  pgstat_read_db_statsfile_timestamp(Oid databaseid, bool permanent,
! 								   TimestampTz *ts)
  {
  	PgStat_StatDBEntry dbentry;
  	PgStat_GlobalStats myGlobalStats;
--- 4121,4127 ----
   */
  static bool
  pgstat_read_db_statsfile_timestamp(Oid databaseid, bool permanent,
! 								   TimestampTz *ts, int elevel)
  {
  	PgStat_StatDBEntry dbentry;
  	PgStat_GlobalStats myGlobalStats;
*************** pgstat_read_db_statsfile_timestamp(Oid d
*** 4136,4142 ****
  	if ((fpin = AllocateFile(statfile, PG_BINARY_R)) == NULL)
  	{
  		if (errno != ENOENT)
! 			ereport(pgStatRunningInCollector ? LOG : WARNING,
  					(errcode_for_file_access(),
  					 errmsg("could not open statistics file \"%s\": %m",
  							statfile)));
--- 4136,4142 ----
  	if ((fpin = AllocateFile(statfile, PG_BINARY_R)) == NULL)
  	{
  		if (errno != ENOENT)
! 			ereport(elevel,
  					(errcode_for_file_access(),
  					 errmsg("could not open statistics file \"%s\": %m",
  							statfile)));
*************** pgstat_read_db_statsfile_timestamp(Oid d
*** 4149,4155 ****
  	if (fread(&format_id, 1, sizeof(format_id), fpin) != sizeof(format_id) ||
  		format_id != PGSTAT_FILE_FORMAT_ID)
  	{
! 		ereport(pgStatRunningInCollector ? LOG : WARNING,
  				(errmsg("corrupted statistics file \"%s\"", statfile)));
  		FreeFile(fpin);
  		return false;
--- 4149,4155 ----
  	if (fread(&format_id, 1, sizeof(format_id), fpin) != sizeof(format_id) ||
  		format_id != PGSTAT_FILE_FORMAT_ID)
  	{
! 		ereport(elevel,
  				(errmsg("corrupted statistics file \"%s\"", statfile)));
  		FreeFile(fpin);
  		return false;
*************** pgstat_read_db_statsfile_timestamp(Oid d
*** 4161,4167 ****
  	if (fread(&myGlobalStats, 1, sizeof(myGlobalStats),
  			  fpin) != sizeof(myGlobalStats))
  	{
! 		ereport(pgStatRunningInCollector ? LOG : WARNING,
  				(errmsg("corrupted statistics file \"%s\"", statfile)));
  		FreeFile(fpin);
  		return false;
--- 4161,4167 ----
  	if (fread(&myGlobalStats, 1, sizeof(myGlobalStats),
  			  fpin) != sizeof(myGlobalStats))
  	{
! 		ereport(elevel,
  				(errmsg("corrupted statistics file \"%s\"", statfile)));
  		FreeFile(fpin);
  		return false;
*************** pgstat_read_db_statsfile_timestamp(Oid d
*** 4186,4192 ****
  				if (fread(&dbentry, 1, offsetof(PgStat_StatDBEntry, tables),
  						  fpin) != offsetof(PgStat_StatDBEntry, tables))
  				{
! 					ereport(pgStatRunningInCollector ? LOG : WARNING,
  							(errmsg("corrupted statistics file \"%s\"",
  									statfile)));
  					goto done;
--- 4186,4192 ----
  				if (fread(&dbentry, 1, offsetof(PgStat_StatDBEntry, tables),
  						  fpin) != offsetof(PgStat_StatDBEntry, tables))
  				{
! 					ereport(elevel,
  							(errmsg("corrupted statistics file \"%s\"",
  									statfile)));
  					goto done;
*************** pgstat_read_db_statsfile_timestamp(Oid d
*** 4208,4214 ****
  				goto done;
  
  			default:
! 				ereport(pgStatRunningInCollector ? LOG : WARNING,
  						(errmsg("corrupted statistics file \"%s\"",
  								statfile)));
  				goto done;
--- 4208,4214 ----
  				goto done;
  
  			default:
! 				ereport(elevel,
  						(errmsg("corrupted statistics file \"%s\"",
  								statfile)));
  				goto done;
*************** backend_read_statsfile(void)
*** 4231,4236 ****
--- 4231,4237 ----
  	TimestampTz min_ts = 0;
  	TimestampTz ref_ts = 0;
  	int			count;
+ 	int			elevel = WARNING;
  
  	/* already read it? */
  	if (pgStatDBHash)
*************** backend_read_statsfile(void)
*** 4250,4256 ****
  
  		CHECK_FOR_INTERRUPTS();
  
! 		ok = pgstat_read_db_statsfile_timestamp(MyDatabaseId, false, &file_ts);
  
  		cur_ts = GetCurrentTimestamp();
  		/* Calculate min acceptable timestamp, if we didn't already */
--- 4251,4257 ----
  
  		CHECK_FOR_INTERRUPTS();
  
! 		ok = pgstat_read_db_statsfile_timestamp(MyDatabaseId, false, &file_ts, elevel);
  
  		cur_ts = GetCurrentTimestamp();
  		/* Calculate min acceptable timestamp, if we didn't already */
*************** backend_read_statsfile(void)
*** 4317,4322 ****
--- 4318,4327 ----
  		if (ok && file_ts >= min_ts)
  			break;
  
+ 		/* Avoid swamping the server log file with failure messages */
+ 		if (!ok)
+ 			elevel = DEBUG2;
+ 
  		/* Not there or too old, so kick the collector and wait a bit */
  		if ((count % PGSTAT_INQ_LOOP_COUNT) == 0)
  			pgstat_send_inquiry(cur_ts, min_ts, MyDatabaseId);