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B* Trees for Tables with LOB ColumnsLocate this document in the navigation structure


The database system creates the following B* trees for the LOB values of a table:

  • One B* tree for the data records (primary tree), sorted by primary key

  • A common B* tree for all the short LOB values (LOB values < 8 KB)

  • One additional B* tree for each long LOB value (LOB values > 8 KB)

For the values of the LOB column, the leaf pages of the primary tree contain either links to the common B* tree for the short LOB values or a link to the B* tree of the respective long LOB value.

The following figure shows the B* trees for a table with a LOB column, which contains two short LOB values and two long LOB values.

Figure 1: Example: B* Trees for a Table with a LOB Column
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