I don't think it is so much a number as "is the index used". You can use the "alter index [no]monitoring" command to turn on monitoring and then watch v$object_usage to see which are used. Make sure you observe over a good time period to ensure you don't miss any reports that are not run too often. From: oracle-l-bounce@xxxxxxxxxxxxx [mailto:oracle-l-bounce@xxxxxxxxxxxxx] On Behalf Of Ram Raman Sent: Thursday, August 11, 2011 2:45 PM To: ORACLE-L Subject: How many is too many Listers, I am looking at a table in our system and it has 12 indexes, we are planning on adding another one. I am aware of the effects of having too many indexes, but in this case adding an extra index helps a certain query that runs slow. Other queries and most other operations against the table are acceptable too. I see a few tables like this; is there a number above which is considered a no-no when it comes to adding more indexes. PS. The tables and queries are structured in a way that seem to require several indexes - it is a third party product. TIA, Ram.