Use pg_locks.waitstart for counting waiting time. (#32)

* Use pg_locks.waitstart for counting waiting time. * Add new memstats metrics. Co-authored-by: Lesovsky Aleksey <[email protected]>
lesovsky · Apr 9, 2022 · 9ed2fef · 9ed2fef
1 parent da4120c
commit 9ed2fef
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Showing 4 changed files with 29 additions and 10 deletions.
diff --git a/internal/collector/linux_memory_test.go b/internal/collector/linux_memory_test.go
@@ -82,7 +82,8 @@ func TestMeminfoCollector_Update(t *testing.T) {
 			"node_vmstat_balloon_migrate", "node_vmstat_swap_ra", "node_vmstat_swap_ra_hit", "node_vmstat_nr_foll_pin_acquired",
 			"node_vmstat_pgsteal_anon", "node_vmstat_pgsteal_file", "node_vmstat_pgscan_file", "node_vmstat_pgscan_anon",
 			"node_vmstat_thp_file_fallback_charge", "node_vmstat_nr_foll_pin_released", "node_vmstat_thp_file_fallback",
-			"node_vmstat_thp_fault_fallback_charge",
+			"node_vmstat_thp_fault_fallback_charge", "node_vmstat_nr_swapcached", "node_vmstat_direct_map_level2_splits",
+			"node_vmstat_direct_map_level3_splits",
 		},
 		collector: NewMeminfoCollector,
 	}

diff --git a/internal/collector/postgres_activity.go b/internal/collector/postgres_activity.go
@@ -17,26 +17,37 @@ const (
 	postgresActivityQuery95 = "SELECT " +
 		"coalesce(usename, 'system') AS user, datname AS database, state, waiting, " +
 		"coalesce(extract(epoch FROM clock_timestamp() - xact_start), 0) AS active_seconds, " +
-		"case when waiting = 't' THEN extract(epoch FROM clock_timestamp() - state_change) ELSE 0 END AS waiting_seconds, " +
-		"left(query, 32) as query " +
+		"CASE WHEN waiting = 't' THEN extract(epoch FROM clock_timestamp() - state_change) ELSE 0 END AS waiting_seconds, " +
+		"left(query, 32) AS query " +
 		"FROM pg_stat_activity"
 
-	// postgresActivityQuery96 defines activity query for 9.6 and older.
+	// postgresActivityQuery96 defines activity query for 9.6.
 	// Postgres 9.6 doesn't have 'backend_type' attribute.
 	postgresActivityQuery96 = "SELECT " +
 		"coalesce(usename, 'system') AS user, datname AS database, state, wait_event_type, wait_event, " +
 		"coalesce(extract(epoch FROM clock_timestamp() - xact_start), 0) AS active_seconds, " +
-		"case when wait_event_type = 'Lock' THEN extract(epoch FROM clock_timestamp() - state_change) ELSE 0 END AS waiting_seconds, " +
-		"left(query, 32) as query " +
+		"CASE WHEN wait_event_type = 'Lock' THEN extract(epoch FROM clock_timestamp() - state_change) ELSE 0 END AS waiting_seconds, " +
+		"left(query, 32) AS query " +
+		"FROM pg_stat_activity"
+
+	// postgresActivityQuery13 defines activity query for versions from 10 to 13.
+	postgresActivityQuery13 = "SELECT " +
+		"coalesce(usename, backend_type) AS user, datname AS database, state, wait_event_type, wait_event, " +
+		"coalesce(extract(epoch FROM clock_timestamp() - xact_start), 0) AS active_seconds, " +
+		"CASE WHEN wait_event_type = 'Lock' THEN extract(epoch FROM clock_timestamp() - state_change) ELSE 0 END AS waiting_seconds, " +
+		"left(query, 32) AS query " +
 		"FROM pg_stat_activity"
 
 	// postgresActivityQueryLatest defines activity query for recent versions.
+	// Postgres 14 has pg_locks.waitstart which is better for taking sessions waiting time.
 	postgresActivityQueryLatest = "SELECT " +
 		"coalesce(usename, backend_type) AS user, datname AS database, state, wait_event_type, wait_event, " +
 		"coalesce(extract(epoch FROM clock_timestamp() - xact_start), 0) AS active_seconds, " +
-		"case when wait_event_type = 'Lock' THEN extract(epoch FROM clock_timestamp() - state_change) ELSE 0 END AS waiting_seconds, " +
-		"left(query, 32) as query " +
-		"FROM pg_stat_activity"
+		"CASE WHEN wait_event_type = 'Lock' " +
+		"THEN (SELECT extract(epoch FROM clock_timestamp() - max(waitstart)) FROM pg_locks l WHERE l.pid = a.pid) " +
+		"ELSE 0 END AS waiting_seconds, " +
+		"left(query, 32) AS query " +
+		"FROM pg_stat_activity a"
 
 	postgresPreparedXactQuery = "SELECT count(*) AS total FROM pg_prepared_xacts"
 
@@ -641,6 +652,8 @@ func selectActivityQuery(version int) string {
 		return postgresActivityQuery95
 	case version < PostgresV10:
 		return postgresActivityQuery96
+	case version < PostgresV14:
+		return postgresActivityQuery13
 	default:
 		return postgresActivityQueryLatest
 	}

diff --git a/internal/collector/postgres_activity_test.go b/internal/collector/postgres_activity_test.go
@@ -219,7 +219,11 @@ func Test_selectActivityQuery(t *testing.T) {
 	}{
 		{version: PostgresV95, want: postgresActivityQuery95},
 		{version: PostgresV96, want: postgresActivityQuery96},
-		{version: PostgresV10, want: postgresActivityQueryLatest},
+		{version: PostgresV10, want: postgresActivityQuery13},
+		{version: PostgresV11, want: postgresActivityQuery13},
+		{version: PostgresV12, want: postgresActivityQuery13},
+		{version: PostgresV13, want: postgresActivityQuery13},
+		{version: PostgresV14, want: postgresActivityQueryLatest},
 	}
 
 	for _, tc := range testcases {

diff --git a/internal/collector/postgres_common.go b/internal/collector/postgres_common.go
@@ -14,6 +14,7 @@ const (
 	PostgresV95 = 90500
 	PostgresV96 = 90600
 	PostgresV10 = 100000
+	PostgresV11 = 110000
 	PostgresV12 = 120000
 	PostgresV13 = 130000
 	PostgresV14 = 140000