An index merge tool helps form, for use by a database server in accessing a database in accordance with a workload of queries, an index configuration or set of indexes that consumes relatively less storage space. The index merge tool identifies from an initial set of indexes one or more combinations of two or more indexes on the same table of the database and merges each identified combination of indexes to form a merged set of indexes. The index merge tool identifies and merges each combination of indexes by identifying and merging one pair of indexes at a time. The index merge tool uses the merged set of indexes as the index configuration for use in executing queries against the database so long as the storage saved by the merged set of indexes exceeds a threshold amount and so long as any increase in the cost to execute queries against the database using the merged set of indexes is limited. Otherwise, the index merge tool uses the initial set of indexes as the index configuration.