An allocation of space, within a container of a table space, to a single database object. This allocation consists of multiple pages.
An extent is a contiguous area of storage in a computer file system, reserved for a file. When a process creates a file, file-system management software allocates a whole extent. When writing to the file again, possibly after doing other write operations, the data continues where the previous write left off. This reduces or eliminates file fragmentation and possibly file scattering too.
An extent-based file system (i.e., one that addresses storage via extents rather than in single blocks) need not require limiting each file to a single, contiguous extent.
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