reduce unnecessary sqlite indexes

db/helpers.go

@@ -354,8 +354,12 @@ func EnsureSnapshotIndexes(ctx context.Context, dbConn *sqlx.DB, tableName strin
 	driver := strings.ToLower(dbConn.DriverName())
 	indexes := []string{
 		fmt.Sprintf(`CREATE INDEX IF NOT EXISTS %s_vm_vcenter_idx ON %s ("VmId","Vcenter")`, tableName, tableName),
-		fmt.Sprintf(`CREATE INDEX IF NOT EXISTS %s_snapshottime_idx ON %s ("SnapshotTime")`, tableName, tableName),
-		fmt.Sprintf(`CREATE INDEX IF NOT EXISTS %s_resourcepool_idx ON %s ("ResourcePool")`, tableName, tableName),
+	}
+	if driver != "sqlite" {
+		indexes = append(indexes,
+			fmt.Sprintf(`CREATE INDEX IF NOT EXISTS %s_snapshottime_idx ON %s ("SnapshotTime")`, tableName, tableName),
+			fmt.Sprintf(`CREATE INDEX IF NOT EXISTS %s_resourcepool_idx ON %s ("ResourcePool")`, tableName, tableName),
+		)
 	}
 	// PG-specific helpful indexes; safe no-ops on SQLite if executed, but keep them gated to reduce file bloat.
 	if driver == "pgx" || driver == "postgres" {
@@ -373,6 +377,86 @@ func EnsureSnapshotIndexes(ctx context.Context, dbConn *sqlx.DB, tableName strin
 	return nil
 }
 
+func listTablesByPrefix(ctx context.Context, dbConn *sqlx.DB, prefix string) ([]string, error) {
+	driver := strings.ToLower(dbConn.DriverName())
+	pattern := prefix + "%"
+	switch driver {
+	case "sqlite":
+		rows, err := dbConn.QueryxContext(ctx, `
+SELECT name
+FROM sqlite_master
+WHERE type = 'table'
+  AND name LIKE ?
+ORDER BY name DESC
+`, pattern)
+		if err != nil {
+			return nil, err
+		}
+		defer rows.Close()
+		var tables []string
+		for rows.Next() {
+			var name string
+			if err := rows.Scan(&name); err != nil {
+				return nil, err
+			}
+			tables = append(tables, name)
+		}
+		return tables, rows.Err()
+	case "pgx", "postgres":
+		rows, err := dbConn.QueryxContext(ctx, `
+SELECT tablename
+FROM pg_catalog.pg_tables
+WHERE schemaname = 'public'
+  AND tablename LIKE $1
+ORDER BY tablename DESC
+`, pattern)
+		if err != nil {
+			return nil, err
+		}
+		defer rows.Close()
+		var tables []string
+		for rows.Next() {
+			var name string
+			if err := rows.Scan(&name); err != nil {
+				return nil, err
+			}
+			tables = append(tables, name)
+		}
+		return tables, rows.Err()
+	default:
+		return nil, fmt.Errorf("unsupported driver: %s", driver)
+	}
+}
+
+// CleanupHourlySnapshotIndexes drops low-value per-table indexes on hourly snapshot tables.
+func CleanupHourlySnapshotIndexes(ctx context.Context, dbConn *sqlx.DB) (int, error) {
+	driver := strings.ToLower(dbConn.DriverName())
+	if driver != "sqlite" {
+		return 0, fmt.Errorf("hourly snapshot index cleanup is only supported for sqlite")
+	}
+	tables, err := listTablesByPrefix(ctx, dbConn, "inventory_hourly_")
+	if err != nil {
+		return 0, err
+	}
+	dropped := 0
+	for _, tableName := range tables {
+		if _, err := SafeTableName(tableName); err != nil {
+			continue
+		}
+		indexes := []string{
+			fmt.Sprintf(`DROP INDEX IF EXISTS %s_snapshottime_idx`, tableName),
+			fmt.Sprintf(`DROP INDEX IF EXISTS %s_resourcepool_idx`, tableName),
+		}
+		for _, stmt := range indexes {
+			if _, err := execLog(ctx, dbConn, stmt); err != nil {
+				return dropped, err
+			}
+			dropped++
+		}
+	}
+	return dropped, nil
+}
+
 // BackfillSerialColumn sets missing values in a serial-like column for Postgres tables.
 func BackfillSerialColumn(ctx context.Context, dbConn *sqlx.DB, tableName, columnName string) error {
 	if err := ValidateTableName(tableName); err != nil {