more optimisation

db/helpers.go

@@ -277,6 +277,12 @@ func EnsureSnapshotTable(ctx context.Context, dbConn *sqlx.DB, tableName string)
 	}
 
 	_, err := dbConn.ExecContext(ctx, ddl)
+	if err != nil {
+		return err
+	}
+
+	index := fmt.Sprintf(`CREATE INDEX IF NOT EXISTS %s_vm_vcenter_idx ON %s ("VmId","Vcenter")`, tableName, tableName)
+	_, err = dbConn.ExecContext(ctx, index)
 	return err
 }
 
@@ -303,6 +309,67 @@ func BackfillSerialColumn(ctx context.Context, dbConn *sqlx.DB, tableName, colum
 	return nil
 }
 
+// ApplySQLiteTuning applies lightweight WAL/synchronous tweaks for better concurrency in non-prod contexts.
+func ApplySQLiteTuning(ctx context.Context, dbConn *sqlx.DB) {
+	if strings.ToLower(dbConn.DriverName()) != "sqlite" {
+		return
+	}
+	// Best-effort pragmas; ignore errors to stay safe in constrained environments.
+	pragmas := []string{
+		`PRAGMA journal_mode=WAL;`,
+		`PRAGMA synchronous=NORMAL;`,
+		`PRAGMA temp_store=MEMORY;`,
+	}
+	for _, pragma := range pragmas {
+		_, _ = dbConn.ExecContext(ctx, pragma)
+	}
+}
+
+// CheckMigrationState ensures goose migrations are present and not dirty.
+func CheckMigrationState(ctx context.Context, dbConn *sqlx.DB) error {
+	driver := strings.ToLower(dbConn.DriverName())
+	var tableExists bool
+	switch driver {
+	case "sqlite":
+		err := dbConn.GetContext(ctx, &tableExists, `
+SELECT COUNT(1) > 0 FROM sqlite_master WHERE type='table' AND name='goose_db_version'
+`)
+		if err != nil {
+			return err
+		}
+	case "pgx", "postgres":
+		err := dbConn.GetContext(ctx, &tableExists, `
+SELECT EXISTS (
+  SELECT 1 FROM pg_tables WHERE schemaname = 'public' AND tablename = 'goose_db_version'
+)
+`)
+		if err != nil {
+			return err
+		}
+	default:
+		return fmt.Errorf("unsupported driver for migration check: %s", driver)
+	}
+
+	if !tableExists {
+		return fmt.Errorf("goose_db_version table not found; database migrations may not be applied")
+	}
+
+	var dirty bool
+	err := dbConn.GetContext(ctx, &dirty, `
+SELECT NOT is_applied
+FROM goose_db_version
+ORDER BY id DESC
+LIMIT 1
+`)
+	if err != nil {
+		return err
+	}
+	if dirty {
+		return fmt.Errorf("database migrations are in a dirty state; please resolve goose_db_version")
+	}
+	return nil
+}
+
 // BuildDailySummaryInsert returns the SQL to aggregate hourly snapshots into a daily summary table.
 func BuildDailySummaryInsert(tableName string, unionQuery string) (string, error) {
 	if _, err := SafeTableName(tableName); err != nil {