US Patent 7555491 Removing overflow rows in a relational database

Techniques to repair overflow rows in a relational database table are described. In one implementation, a source table's physical memory pages are interrogated to identify overflow rows. In another implementation, overflow rows generated during database update operations are identified from non-table sources (e.g., log files). In general, overflow rows are repaired by: unloading one or more rows identified as overflow rows; locking the source table from outside access; disabling or deleting any associations associated with the unloaded rows; deleting the identified overflow/unloaded rows from the source table; reloading the previously unloaded rows back into the source table; restoring any associations previously disabled/deleted; and unlocking the tables. Rows may be processed in groups small enough not to significantly impact users accessing either the source or associated tables.