Sbpages

An sbpage is the type of page that the database server uses to store smart large objects within an sbspace. Unlike blobpages, sbpages are not configurable. An sbpage is the same size as the database server page, which is usually 2 KB on UNIX and 4 KB on Windows.

The unit of allocation in an sbspace is an extent, whereas the unit of allocation in a blobspace is a blobpage. Just as with pages in a chunk, a certain number of smart large object extents compose a chunk in an sbspace, as the following figure illustrates. An extent is always entirely contained in a chunk and cannot cross chunk boundaries.
Figure 1. A chunk in an sbspace, logically separated into a series of extents
This figure shows a chunk containing some smart large object extents. The size of a smart large object extent is calculated by the database server.

Smart large objects cannot be stored in a dbspace or blobspace. For more information, see Sbspaces, and sbspace structure in the disk structures and storage chapter of the HCL Informix® Administrator's Reference.

The database server calculates the extent size for a smart large object from a set of heuristics, such as the number of bytes in a write operation. For more information, see Extent sizes for sbspaces.


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