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Oracle 9i Tablespace Changes

• The tablespace will use the default free space management setting of SEGMENT SPACE MANAGEMENT MANUAL. As a result, Oracle will use freelists to manage free space within segments in the tablespace. Free lists are lists of data blocks that have space available for inserting rows.

Administrators have the option of overriding the default specification of SEGMENT SPACE MANAGEMENT MANUAL with SEGMENT SPACE MANAGEMENT AUTO. SEGMENT SPACE MANAGEMENT AUTO tells Oracle to use bitmaps to manage free space within a segment. The bitmap structure stores information that describes the amount of space in the blocks that are available for row inserts.

As free space within each block grows and shrinks, its new state is reflected in the bitmap. Bitmaps allow Oracle to manage free space more automatically. As a result, tracking free space within segments using bitmaps provides a simpler and more efficient method of free space management. Only permanent, locally managed tablespaces can specify automatic segment space management.

• The extent management will be AUTOALLOCATE (extent sizes defined and managed by Oracle) because a default storage clause is not be specified. If the default storage clause is not specified, or if it is specified with PCTINCREASE not equal to 0 and/or INITIAL not equal to NEXT, then Oracle creates a locally managed tablespace with extents managed automatically (AUTOALLOCATE).
  

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