Hi, as it was suggested by our Agent, and after checking; Indexing can help if those columns are frequently used in JOINs or filters, especially high-cardinality columns (such as IDs or dates). In general, indexing the underlying base table columns used in joins and common dashboard filters is beneficial. The guidance is to index only the most impactful columns, since too many indexes increase storage and slow down data loads. GoodData does not provide specific recommendations about indexing columns solely because they appear in WHERE clauses of subqueries. Instead, the focus is on join keys and frequently used analytical attributes. You can find the official guidance here: https://www.gooddata.com/docs/cloud/connect-data/performance/#index