Extensibility Enhancements

This release includes the following improvements in the area of extensibility.

DeepCopy Function for Multirepresentational Data Types

Use the DeepCopy function for user-defined types with multiple representations, such as images. The DeepCopy function copies the user-defined type so that the user can safely allocate both the in-row value and out-of-row data with the default memory duration.

After you register the DeepCopy function for the multirepresentational types, the database server automatically invokes DeepCopy.

Nearest Neighbor Queries in R-Trees

R-tree indexes support nearest-neighbor queries. A nearest-neighbor query asks for items in a spatial database that are the nearest to a specific location or object. If you do a nearest-neighbor query on a map of the San Jose area, Santa Clara would be the nearest neighbor, but not San Francisco. Version 9.3 supports composite R-tree indexes.

For more information, see the IBM Informix R-Tree Index User's Guide.

Temporary Sbspaces and Smart Large Objects

Smart-large-object performance is significantly faster for certain operations. Writes to temporary smart large objects are faster than for standard smart large objects.

Use temporary smart large objects to store text, image, or user-defined data that you need temporarily for a user session. You can store temporary smart large objects in a standard sbspace or temporary sbspace. If temporary smart large objects are stored in a temporary sbspace, the metadata and user data are not logged.

To specify the default temporary sbspace, use the SBSPACETEMP configuration parameter.

Improved Space Allocation of User Data and Metadata in Sbspaces

The database server reserves 40 percent of the user-data space in the sbspace chunk. When the chunk runs out of metadata or user-data space, the database server moves some of the reserved space to the corresponding area. This feature enables the database server to use the space in the sbspace more efficiently.