Include PID in replication_outgoing entries

Author: mdevan

collector/collect.go

@@ -555,7 +555,8 @@ func (c *collector) getReplicationv10() {
 			COALESCE(EXTRACT(EPOCH FROM flush_lag)::bigint, 0),
 			COALESCE(EXTRACT(EPOCH FROM replay_lag)::bigint, 0),
 			COALESCE(sync_priority, -1),
-			COALESCE(sync_state, '')
+			COALESCE(sync_state, ''),
+			pid
 		  FROM pg_stat_replication
 		  ORDER BY pid ASC`
 	rows, err := c.db.QueryContext(ctx, q)
@@ -571,7 +572,7 @@ func (c *collector) getReplicationv10() {
 		if err := rows.Scan(&r.RoleName, &r.ApplicationName, &r.ClientAddr,
 			&r.BackendStart, &backendXmin, &r.State, &r.SentLSN, &r.WriteLSN,
 			&r.FlushLSN, &r.ReplayLSN, &r.WriteLag, &r.FlushLag, &r.ReplayLag,
-			&r.SyncPriority, &r.SyncState); err != nil {
+			&r.SyncPriority, &r.SyncState, &r.PID); err != nil {
 			log.Fatalf("pg_stat_replication query failed: %v", err)
 		}
 		r.BackendXmin = int(backendXmin.Int64)
@@ -595,7 +596,8 @@ func (c *collector) getReplicationv9() {
 			COALESCE(flush_location::text, ''),
 			COALESCE(replay_location::text, ''),
 			COALESCE(sync_priority, -1),
-			COALESCE(sync_state, '')
+			COALESCE(sync_state, ''),
+			pid
 		  FROM pg_stat_replication
 		  ORDER BY pid ASC`
 	if c.version < 90400 { // backend_xmin is only in v9.4+
@@ -613,7 +615,7 @@ func (c *collector) getReplicationv9() {
 		var backendXmin sql.NullInt64
 		if err := rows.Scan(&r.RoleName, &r.ApplicationName, &r.ClientAddr,
 			&r.BackendStart, &backendXmin, &r.State, &r.SentLSN, &r.WriteLSN,
-			&r.FlushLSN, &r.ReplayLSN, &r.SyncPriority, &r.SyncState); err != nil {
+			&r.FlushLSN, &r.ReplayLSN, &r.SyncPriority, &r.SyncState, &r.PID); err != nil {
 			log.Fatalf("pg_stat_replication query failed: %v", err)
 		}
 		r.BackendXmin = int(backendXmin.Int64)

model.go

@@ -18,12 +18,13 @@ package pgmetrics
 
 // ModelSchemaVersion is the schema version of the "Model" data structure
 // defined below. It is in the "semver" notation. Version history:
+//    1.5 - add PID to replication_outgoing entries
 //    1.4 - pgbouncer information
 //    1.3 - locks information
 //    1.2 - more table and index attributes
 //    1.1 - added NotificationQueueUsage and Statements
 //    1.0 - initial release
-const ModelSchemaVersion = "1.4"
+const ModelSchemaVersion = "1.5"
 
 // Model contains the entire information collected by a single run of
 // pgmetrics. It can be converted to and from json without loss of
@@ -432,6 +433,8 @@ type ReplicationOut struct {
 	ReplayLag       int    `json:"replay_lag"` // only in 10.x
 	SyncPriority    int    `json:"sync_priority"`
 	SyncState       string `json:"sync_state"`
+	// following fields present only in schema 1.5 and later
+	PID int `json:"pid,omitempty"`
 }
 
 type ReplicationIn struct {