An extent must occupy contiguous space in your tablespace's datafile. When an extent is allocated (initially or subsequently), Oracle must find enough contiguous free space for that extent. Once if finds that space, the extent is allocated. If there is not enough contiguous free space, Oracle will give you an error.
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.