Track temporary file count and size in pg_stat_database

Add counters for number and size of temporary files used
for spill-to-disk queries for each database to the
pg_stat_database view.

Tomas Vondra, review by Magnus Hagander

4 files changed, 101 insertions, 20 deletions

diff --git a/src/backend/catalog/system_views.sql b/src/backend/catalog/system_views.sql
index e25914b306..873d67f0ea 100644
--- a/src/backend/catalog/system_views.sql
+++ b/src/backend/catalog/system_views.sql
@@ -576,6 +576,8 @@ CREATE VIEW pg_stat_database AS
             pg_stat_get_db_tuples_updated(D.oid) AS tup_updated,
             pg_stat_get_db_tuples_deleted(D.oid) AS tup_deleted,
             pg_stat_get_db_conflict_all(D.oid) AS conflicts,
+            pg_stat_get_db_temp_files(D.oid) AS temp_files,
+            pg_stat_get_db_temp_bytes(D.oid) AS temp_bytes,
             pg_stat_get_db_stat_reset_time(D.oid) AS stats_reset
     FROM pg_database D;
 
diff --git a/src/backend/postmaster/pgstat.c b/src/backend/postmaster/pgstat.c
index e5bafd3c2d..3b7aa07014 100644
--- a/src/backend/postmaster/pgstat.c
+++ b/src/backend/postmaster/pgstat.c
@@ -286,6 +286,7 @@ static void pgstat_recv_bgwriter(PgStat_MsgBgWriter *msg, int len);
 static void pgstat_recv_funcstat(PgStat_MsgFuncstat *msg, int len);
 static void pgstat_recv_funcpurge(PgStat_MsgFuncpurge *msg, int len);
 static void pgstat_recv_recoveryconflict(PgStat_MsgRecoveryConflict *msg, int len);
+static void pgstat_recv_tempfile(PgStat_MsgTempFile *msg, int len);
 
 
 /* ------------------------------------------------------------
@@ -1339,6 +1340,29 @@ pgstat_report_recovery_conflict(int reason)
 	pgstat_send(&msg, sizeof(msg));
 }
 
+
+/* --------
+ * pgstat_report_tempfile() -
+ *
+ *	Tell the collector about a temporary file.
+ * --------
+ */
+void
+pgstat_report_tempfile(size_t filesize)
+{
+	PgStat_MsgTempFile msg;
+
+	if (pgStatSock == PGINVALID_SOCKET || !pgstat_track_counts)
+		return;
+
+	pgstat_setheader(&msg.m_hdr, PGSTAT_MTYPE_TEMPFILE);
+	msg.m_databaseid = MyDatabaseId;
+	msg.m_filesize = filesize;
+	pgstat_send(&msg, sizeof(msg));
+}
+
+;
+
 /* ----------
  * pgstat_ping() -
  *
@@ -3218,6 +3242,10 @@ PgstatCollectorMain(int argc, char *argv[])
 					pgstat_recv_recoveryconflict((PgStat_MsgRecoveryConflict *) &msg, len);
 					break;
 
+				case PGSTAT_MTYPE_TEMPFILE:
+					pgstat_recv_tempfile((PgStat_MsgTempFile *) &msg, len);
+					break;
+
 				default:
 					break;
 			}
@@ -3299,6 +3327,8 @@ pgstat_get_db_entry(Oid databaseid, bool create)
 		result->n_conflict_snapshot = 0;
 		result->n_conflict_bufferpin = 0;
 		result->n_conflict_startup_deadlock = 0;
+		result->n_temp_files = 0;
+		result->n_temp_bytes = 0;
 
 		result->stat_reset_timestamp = GetCurrentTimestamp();
 
@@ -4210,6 +4240,8 @@ pgstat_recv_resetcounter(PgStat_MsgResetcounter *msg, int len)
 	dbentry->n_tuples_updated = 0;
 	dbentry->n_tuples_deleted = 0;
 	dbentry->last_autovac_time = 0;
+	dbentry->n_temp_bytes = 0;
+	dbentry->n_temp_files = 0;
 
 	dbentry->stat_reset_timestamp = GetCurrentTimestamp();
 
@@ -4436,6 +4468,24 @@ pgstat_recv_recoveryconflict(PgStat_MsgRecoveryConflict *msg, int len)
 }
 
 /* ----------
+ * pgstat_recv_tempfile() -
+ *
+ *	Process as PGSTAT_MTYPE_TEMPFILE message.
+ * ----------
+ */
+static void
+pgstat_recv_tempfile(PgStat_MsgTempFile *msg, int len)
+{
+	PgStat_StatDBEntry *dbentry;
+
+	dbentry = pgstat_get_db_entry(msg->m_databaseid, true);
+
+	dbentry->n_temp_bytes += msg->m_filesize;
+	dbentry->n_temp_files += 1;
+
+}
+
+/* ----------
  * pgstat_recv_funcstat() -
  *
  *	Count what the backend has done.
diff --git a/src/backend/storage/file/fd.c b/src/backend/storage/file/fd.c
index 43bc43ab10..673b25db34 100644
--- a/src/backend/storage/file/fd.c
+++ b/src/backend/storage/file/fd.c
@@ -1088,6 +1088,9 @@ FileClose(File file)
 	 */
 	if (vfdP->fdstate & FD_TEMPORARY)
 	{
+		struct stat filestats;
+		int			stat_errno;
+
 		/*
 		 * If we get an error, as could happen within the ereport/elog calls,
 		 * we'll come right back here during transaction abort.  Reset the
@@ -1101,23 +1104,22 @@ FileClose(File file)
 		temporary_files_size -= vfdP->fileSize;
 		vfdP->fileSize = 0;
 
-		if (log_temp_files >= 0)
-		{
-			struct stat filestats;
-			int			stat_errno;
+		/* first try the stat() */
+		if (stat(vfdP->fileName, &filestats))
+			stat_errno = errno;
+		else
+			stat_errno = 0;
 
-			/* first try the stat() */
-			if (stat(vfdP->fileName, &filestats))
-				stat_errno = errno;
-			else
-				stat_errno = 0;
+		/* in any case do the unlink */
+		if (unlink(vfdP->fileName))
+			elog(LOG, "could not unlink file \"%s\": %m", vfdP->fileName);
 
-			/* in any case do the unlink */
-			if (unlink(vfdP->fileName))
-				elog(LOG, "could not unlink file \"%s\": %m", vfdP->fileName);
+		/* and last report the stat results */
+		if (stat_errno == 0)
+		{
+			pgstat_report_tempfile(filestats.st_size);
 
-			/* and last report the stat results */
-			if (stat_errno == 0)
+			if (log_temp_files >= 0)
 			{
 				if ((filestats.st_size / 1024) >= log_temp_files)
 					ereport(LOG,
@@ -1131,12 +1133,6 @@ FileClose(File file)
 				elog(LOG, "could not stat file \"%s\": %m", vfdP->fileName);
 			}
 		}
-		else
-		{
-			/* easy case, just do the unlink */
-			if (unlink(vfdP->fileName))
-				elog(LOG, "could not unlink file \"%s\": %m", vfdP->fileName);
-		}
 	}
 
 	/* Unregister it from the resource owner */
diff --git a/src/backend/utils/adt/pgstatfuncs.c b/src/backend/utils/adt/pgstatfuncs.c
index ed39f27ef4..c7b91a8c82 100644
--- a/src/backend/utils/adt/pgstatfuncs.c
+++ b/src/backend/utils/adt/pgstatfuncs.c
@@ -79,6 +79,8 @@ extern Datum pg_stat_get_db_conflict_bufferpin(PG_FUNCTION_ARGS);
 extern Datum pg_stat_get_db_conflict_startup_deadlock(PG_FUNCTION_ARGS);
 extern Datum pg_stat_get_db_conflict_all(PG_FUNCTION_ARGS);
 extern Datum pg_stat_get_db_stat_reset_time(PG_FUNCTION_ARGS);
+extern Datum pg_stat_get_db_temp_files(PG_FUNCTION_ARGS);
+extern Datum pg_stat_get_db_temp_bytes(PG_FUNCTION_ARGS);
 
 extern Datum pg_stat_get_bgwriter_timed_checkpoints(PG_FUNCTION_ARGS);
 extern Datum pg_stat_get_bgwriter_requested_checkpoints(PG_FUNCTION_ARGS);
@@ -1214,6 +1216,37 @@ pg_stat_get_db_stat_reset_time(PG_FUNCTION_ARGS)
 }
 
 Datum
+pg_stat_get_db_temp_files(PG_FUNCTION_ARGS)
+{
+	Oid		dbid = PG_GETARG_OID(0);
+	int64	result;
+	PgStat_StatDBEntry *dbentry;
+
+	if ((dbentry = pgstat_fetch_stat_dbentry(dbid)) == NULL)
+		result = 0;
+	else
+		result = dbentry->n_temp_files;
+
+	PG_RETURN_INT64(result);
+}
+
+
+Datum
+pg_stat_get_db_temp_bytes(PG_FUNCTION_ARGS)
+{
+	Oid		dbid = PG_GETARG_OID(0);
+	int64	result;
+	PgStat_StatDBEntry *dbentry;
+
+	if ((dbentry = pgstat_fetch_stat_dbentry(dbid)) == NULL)
+		result = 0;
+	else
+		result = dbentry->n_temp_bytes;
+
+	PG_RETURN_INT64(result);
+}
+
+Datum
 pg_stat_get_db_conflict_tablespace(PG_FUNCTION_ARGS)
 {
 	Oid			dbid = PG_GETARG_OID(0);