Cleanup old entries from resource_last_import_time table. (#112438)

* Cleanup old entries from resource_last_import_time table.

* Add index for last_import_time column.

* Address review feedback.

pkg/storage/unified/sql/db/migrations/resource_mig.go

@@ -116,7 +116,7 @@ func initResourceTables(mg *migrator.Migrator) string {
 		},
 	})
 
-	tables = append(tables, migrator.Table{
+	resource_last_import_time := migrator.Table{
 		Name: "resource_last_import_time",
 		Columns: []*migrator.Column{
 			{Name: "group", Type: migrator.DB_NVarchar, Length: 190, Nullable: false},
@@ -125,7 +125,8 @@ func initResourceTables(mg *migrator.Migrator) string {
 			{Name: "last_import_time", Type: migrator.DB_DateTime, Nullable: false},
 		},
 		PrimaryKeys: []string{"group", "resource", "namespace"},
-	})
+	}
+	tables = append(tables, resource_last_import_time)
 
 	// Initialize all tables
 	for t := range tables {
@@ -178,5 +179,11 @@ func initResourceTables(mg *migrator.Migrator) string {
 		Name: "IDX_resource_history_namespace_group_resource_name_generation",
 	}))
 
+	mg.AddMigration("Add UQE_resource_last_import_time_last_import_time index", migrator.NewAddIndexMigration(resource_last_import_time, &migrator.Index{
+		Cols: []string{"last_import_time"},
+		Type: migrator.IndexType,
+		Name: "UQE_resource_last_import_time_last_import_time",
+	}))
+
 	return marker
 }