This document summarizes different types of database indexes that can improve query performance, including value-list indexes, bitmap indexes, projection indexes, and bit-sliced indexes. It compares how each index type can be used to efficiently evaluate single-column sum aggregates and range predicates. The document also discusses how join indexes and bitmap join indexes can help support ad-hoc OLAP-style queries on dimensional data when the query criteria are not known in advance. Segmentation and clustering techniques are also presented to further improve grouping efficiency in data warehousing environments.