I'd love to use the LASTUSED column on SYSIBM.SYSINDEXSTATS introduced in DB2 9 to eliminate indexes. I can show my client a number of indexes that have not been used since DB2 9 was installed in July 2009. But I know they will ask 'what is the ROI on deleting these indexes?'. Is there any 'general rule of thumb' in the performance arena of how much more CPU each additional index on a table would incur? I recall hearing a general number of 10-15% added CPU for a transaction's for each additional index. If I can get a ballpark idea I might be able to get my client to take a look at deleting at least a few indexes on tables with medium to high activity. Any clues / hints / tricks would be welcome.