US Patent 10152511 Techniques for optimization of inner queries

In an on demand database system, a query engine applies a custom index for inner queries. The query engine receives a query and determines that the query has an inner query nested within the primary query. The query engine identifies that a custom index exists for a client associated with the query, and applies the custom index to filter results for the query. The custom index includes a subset of information of a table that includes accounts for multiple different clients. By using the custom index, the query engine can filter the results more efficiently that if solely using the multiple client table.