count tablets post-match

Signed-off-by: Tim Vaillancourt <[email protected]>

go/vt/vtorc/logic/tablet_discovery.go

@@ -167,7 +167,6 @@ func getAllTablets(ctx context.Context, cells []string) (tabletsByCell map[strin
 	var mu sync.Mutex
 	failedCells = make([]string, 0, len(cells))
 	tabletsByCell = make(map[string][]*topo.TabletInfo, len(cells))
-	newTabletsWatchedByCell := make(map[string]int64)
 	eg, ctx := errgroup.WithContext(ctx)
 	for _, cell := range cells {
 		eg.Go(func() error {
@@ -179,13 +178,11 @@ func getAllTablets(ctx context.Context, cells []string) (tabletsByCell map[strin
 				failedCells = append(failedCells, cell)
 			} else {
 				tabletsByCell[cell] = tablets
-				newTabletsWatchedByCell[cell] = int64(len(tablets))
 			}
 			return nil
 		})
 	}
 	_ = eg.Wait() // always nil
-	tabletsWatchedByCell = newTabletsWatchedByCell
 	return tabletsByCell, failedCells
 }
 
@@ -220,6 +217,7 @@ func refreshTabletsUsing(ctx context.Context, loader func(tabletAlias string), f
 
 	// Update each cell that provided a response. This ensures only cells that provided a
 	// response are updated in the backend and are considered for forgetting stale tablets.
+	newTabletsWatchedByCell := make(map[string]int64)
 	for cell, tablets := range tabletsByCell {
 		// Filter tablets that should not be watched using func shouldWatchTablet.
 		matchedTablets := make([]*topo.TabletInfo, 0, len(tablets))
@@ -235,7 +233,10 @@ func refreshTabletsUsing(ctx context.Context, loader func(tabletAlias string), f
 		query := "select alias from vitess_tablet where cell = ?"
 		args := sqlutils.Args(cell)
 		refreshTablets(matchedTablets, query, args, loader, forceRefresh, nil)
+
+		newTabletsWatchedByCell[cell] = int64(len(matchedTablets))
 	}
+	tabletsWatchedByCell = newTabletsWatchedByCell
 
 	return nil
 }