When you create the index, Oracle performs a full table scan, collecting the smbolic key and ROWID for each row in the table. Plus, Oracle writes the TEMP segments in discontiguous segments. A rough estimate is to multiply the ROWID*symbolic_key*num_rows, times a fudge factor of 1.5.
Dig Deeper on Oracle database design and architecture
Have a question for an expert?
Please add a title for your question
Get answers from a TechTarget expert on whatever's puzzling you.