Adding an Overflow Segment
For index-organized tables, it is common, and even recommended, to create an overflow area for row data as part of the overall index-organized table structure. The typical index-organized table that includes an overflow area is structured as follows:
- B-tree index entry, which includes the following:
- Primary key columns
- Some non-key columns depending on
PCTTHRESHOLD
andINCLUDING
clause values specified - Physical
ROWID
pointer to overflow segment
- Overflow segment, which contains the remaining non-key column values
In a normal B-tree index, the leaf node contains the index column key value, and then the ROWID
for the row in the data segment. With index-organized tables, all the non-key column values are stored within ...
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