Good afternoon,

During a life cycle of a table, it grows (insert) and reduces (delete) in terms of row counts but it term of space this is not the case.

My understanding is when you delete rows, the free blocks/extends aren't release and can be used later if new rows are inserted.

Those 'unused' blocks are still scanned during a table scan which are useless. One solution to get rid off of those unneeded reads is to rebuild the object.

Hence I'm looking a way (SQL statement, report) that will tell me or give hints if a table should be rebuild, for example number of free/used extents per segment (in my case I have one segmet per table) or number of free/used extents per datafile per segment.

Is my approach correct?

Thanks in advance

Simon