R-Tree Index Options

This section discusses the options to the CREATE INDEX command that R-tree indexes support.

Using the FRAGMENT Clause

R-tree indexes can be fragmented by expression. You cannot, however, fragment R-tree indexes on the multidimensional column they index.

For example, if you create an R-tree index on a column of type MyShape, you cannot specify this column in the fragment clause. You must fragment the R-tree index on another column of a standard data type, such as INTEGER or VARCHAR.

If you create an R-tree index on a fragmented table in a dbspace with the default page size, the R-tree index is also fragmented by default. The index fragments are automatically stored in the same dbspace as the table fragments. You cannot create an R-tree index on a fragmented table in a dbspace with a non-default page size.

The next section describes where you can store R-tree indexes or fragments of R-tree indexes.

Using the IN Clause

R-tree indexes are stored in dbspaces. If you do not specify an IN clause when you create an R-tree index, the index is stored in the same dbspace or dbspaces as the table on which it is built and inherits the distribution scheme of the table.

You cannot store R-tree indexes in sbspaces. If you specify an sbspace in the IN clause of the CREATE INDEX statement, the index is actually stored in the same dbspace or dbspaces as the table.