Cosmetic improvements

cmd/server/main.go

@@ -338,7 +338,7 @@ func run(ctx context.Context, cfg common.ConfigStore, stderr io.Writer, listener
 		Store:     businessDB,
 	})
 	jobs.AddLocked(1*time.Hour, &maintenance.UserEmailNotificationsJob{
-		RunInterval:  1 * time.Hour,
+		RunInterval:  3 * time.Hour, // overlap few locked intervals to cover for possible unprocessed notifications
 		Store:        businessDB,
 		Templates:    email.Templates(),
 		Sender:       sender,

pkg/maintenance/email.go

@@ -193,7 +193,13 @@ func (j *UserEmailNotificationsJob) retrievePendingNotifications(ctx context.Con
 	return filtered, nil
 }
 
+// NOTE: we should NOT refactor this into "while we have pending notifications {}" loop because some notifications
+// are unprocessable by design (e.g. "subscribed-only" notifications for users who don't have subscriptions), therefore
+// there are cases when there will always be "pending" notifications.
+// If we are not managing to process all of them, we need to modify ChunkSize and Interval (or Lock Inteval) instead
 func (j *UserEmailNotificationsJob) RunOnce(ctx context.Context) error {
+	// TODO: Monitor pending notifications count in Postgres
+	// so we will know if we have enough processing capacity
 	notifications, err := j.retrievePendingNotifications(ctx)
 	if err != nil {
 		slog.ErrorContext(ctx, "Failed to retrieve pending user notifications", common.ErrAttr(err))