improve tracking of VM deletions

internal/tasks/dailyAggregate.go

@@ -67,6 +67,10 @@ func (c *CronTask) aggregateDailySummary(ctx context.Context, targetTime time.Ti
 	hourlyTables := make([]string, 0, len(hourlySnapshots))
 	for _, snapshot := range hourlySnapshots {
 		hourlyTables = append(hourlyTables, snapshot.TableName)
+		// Ensure indexes exist on historical hourly tables for faster aggregation.
+		if err := db.EnsureSnapshotIndexes(ctx, dbConn, snapshot.TableName); err != nil {
+			c.Logger.Warn("failed to ensure indexes on hourly table", "table", snapshot.TableName, "error", err)
+		}
 	}
 	unionQuery, err := buildUnionQuery(hourlyTables, summaryUnionColumns, templateExclusionFilter())
 	if err != nil {