Track last time for statistics reset on databases and bgwriter

Tracks one counter for each database, which is reset whenever
the statistics for any individual object inside the database is
reset, and one counter for the background writer.

Tomas Vondra, reviewed by Greg Smith

3 files changed, 8 insertions, 2 deletions

diff --git a/src/include/catalog/catversion.h b/src/include/catalog/catversion.h
index 18739adb391..aa40e221021 100644
--- a/src/include/catalog/catversion.h
+++ b/src/include/catalog/catversion.h
@@ -53,6 +53,6 @@
  */
 
 /*							yyyymmddN */
-#define CATALOG_VERSION_NO	201102091
+#define CATALOG_VERSION_NO	201102101
 
 #endif
diff --git a/src/include/catalog/pg_proc.h b/src/include/catalog/pg_proc.h
index 9e6ec3dda50..01b002a1454 100644
--- a/src/include/catalog/pg_proc.h
+++ b/src/include/catalog/pg_proc.h
@@ -3131,6 +3131,8 @@ DATA(insert OID = 3069 (  pg_stat_get_db_conflict_startup_deadlock PGNSP PGUID 1
 DESCR("statistics: recovery conflicts in database caused by buffer deadlock");
 DATA(insert OID = 3070 (  pg_stat_get_db_conflict_all PGNSP PGUID 12 1 0 0 f f f t f s 1 0 20 "26" _null_ _null_ _null_ _null_ pg_stat_get_db_conflict_all _null_ _null_ _null_ ));
 DESCR("statistics: recovery conflicts in database");
+DATA(insert OID = 3074 (  pg_stat_get_db_stat_reset_time PGNSP PGUID 12 1 0 0 f f f t f s 1 0 1184 "26" _null_ _null_ _null_ _null_	pg_stat_get_db_stat_reset_time _null_ _null_ _null_ ));
+DESCR("statistics: last reset for a database");
 DATA(insert OID = 2769 ( pg_stat_get_bgwriter_timed_checkpoints PGNSP PGUID 12 1 0 0 f f f t f s 0 0 20 "" _null_ _null_ _null_ _null_ pg_stat_get_bgwriter_timed_checkpoints _null_ _null_ _null_ ));
 DESCR("statistics: number of timed checkpoints started by the bgwriter");
 DATA(insert OID = 2770 ( pg_stat_get_bgwriter_requested_checkpoints PGNSP PGUID 12 1 0 0 f f f t f s 0 0 20 "" _null_ _null_ _null_ _null_ pg_stat_get_bgwriter_requested_checkpoints _null_ _null_ _null_ ));
@@ -3141,6 +3143,8 @@ DATA(insert OID = 2772 ( pg_stat_get_bgwriter_buf_written_clean PGNSP PGUID 12 1
 DESCR("statistics: number of buffers written by the bgwriter for cleaning dirty buffers");
 DATA(insert OID = 2773 ( pg_stat_get_bgwriter_maxwritten_clean PGNSP PGUID 12 1 0 0 f f f t f s 0 0 20 "" _null_ _null_ _null_ _null_ pg_stat_get_bgwriter_maxwritten_clean _null_ _null_ _null_ ));
 DESCR("statistics: number of times the bgwriter stopped processing when it had written too many buffers while cleaning");
+DATA(insert OID = 3075 ( pg_stat_get_bgwriter_stat_reset_time PGNSP PGUID 12 1 0 0 f f f t f s 0 0 1184 "" _null_ _null_ _null_ _null_	pg_stat_get_bgwriter_stat_reset_time _null_ _null_ _null_ ));
+DESCR("statistics: last reset for the bgwriter");
 DATA(insert OID = 2775 ( pg_stat_get_buf_written_backend PGNSP PGUID 12 1 0 0 f f f t f s 0 0 20 "" _null_ _null_ _null_ _null_ pg_stat_get_buf_written_backend _null_ _null_ _null_ ));
 DESCR("statistics: number of buffers written by backends");
 DATA(insert OID = 3063 ( pg_stat_get_buf_fsync_backend PGNSP PGUID 12 1 0 0 f f f t f s 0 0 20 "" _null_ _null_ _null_ _null_ pg_stat_get_buf_fsync_backend _null_ _null_ _null_ ));
diff --git a/src/include/pgstat.h b/src/include/pgstat.h
index 9f4e0cac9b8..0414b19868e 100644
--- a/src/include/pgstat.h
+++ b/src/include/pgstat.h
@@ -484,7 +484,7 @@ typedef union PgStat_Msg
  * ------------------------------------------------------------
  */
 
-#define PGSTAT_FILE_FORMAT_ID	0x01A5BC98
+#define PGSTAT_FILE_FORMAT_ID	0x01A5BC99
 
 /* ----------
  * PgStat_StatDBEntry			The collector's data per database
@@ -508,6 +508,7 @@ typedef struct PgStat_StatDBEntry
 	PgStat_Counter n_conflict_snapshot;
 	PgStat_Counter n_conflict_bufferpin;
 	PgStat_Counter n_conflict_startup_deadlock;
+	TimestampTz stat_reset_timestamp;
 
 
 	/*
@@ -584,6 +585,7 @@ typedef struct PgStat_GlobalStats
 	PgStat_Counter buf_written_backend;
 	PgStat_Counter buf_fsync_backend;
 	PgStat_Counter buf_alloc;
+	TimestampTz stat_reset_timestamp;
 } PgStat_GlobalStats;