fix: failed to read replication lag: cannot assign NULL to int

Description

We get an error if the sync instance (for some reason) is not in recovery mode, since the request in this case returned NULL.

Fixed:

2022/09/23 18:52:51 retrieval_status.go:108: [WARNING] Failed to fetch replication lag failed to read replication lag: can't scan into dest[0]: cannot assign NULL to *int

Related issue

Examples

Checklist

• MR description has been reviewed
• MR changes are functionally tested
• MR does NOT have text changes OR there are text changes and they have been reviewed
• MR does NOT have API/CLI changes OR there are API/CLI changes and they have been reviewed
• MR does NOT have UI changes OR there are UI changes and they have been reviewed

engine/internal/retrieval/status/retrieval_status.go

@@ -32,6 +32,7 @@ const (
 			  ELSE
 				coalesce(round(date_part('epoch', now() - pg_last_xact_replay_timestamp())::int8, 0), 0)
 			  END)
+		  ELSE 0
 		  END lag_sec;
 	`
 
@@ -43,6 +44,7 @@ const (
 			  ELSE
 				coalesce(round(date_part('epoch', now() - pg_last_xact_replay_timestamp())::int8, 0), 0)
 			  END)
+		  ELSE 0
 		  END lag_sec;
 	`