TUNE INDEX

The TUNE INDEX utility performs the following functions:

Adopts orphans in an index structure. An orphaned indexed record is a record whose index pointer does not point back to the index record (SR8) that contains the record's index entry. Orphans occur as the result of splitting an existing SR8 into two records to accommodate a new entry. As part of the split, some of the entries are moved to a new SR8, but the index pointer in their associated records is not adjusted to reflect the change, resulting in "orphaned" records. By eliminating orphans, runtime database performance is improved when traversing from an indexed record to its associated index entry.
Moves the top level SR8 to its optimal location.
Optionally rebalances the index structure. Rebalancing ensures that the resulting index structure is a balanced tree and has a minimal number of levels and SR8's. You can temporarily override the index block contains value of the index and the page reserve value of the area that contains the index structure. Using these overrides allows tuning the index while allowing for future growth.
Optionally resequences the index structure. Resequencing puts the SR8 records in physical sequence. By resequencing the index structure, database performance is improved when accessing the index structure sequentially at the bottom level.

Note: Under some circumstances the process of moving the top level SR8 to its optimal location might cause some degree of resequencing to be performed even if RESEQUENCE NO is specified, or when the RESEQUENCE option is allowed to default to NO.

Authorization

A user must have DBAWRITE authority on all areas processed by the utility.