Scatter Factor in the dbanalys or tabanalys shows the degree of distance between records in the table.
The scatter factor indicates when one would benefit from a table reorg (dump and load) due to unused free space between records of the object.
The optimal value for this field varies from database to database.
The best achievable Scatter Index value is that of a freshly loaded database with no simultaneous load running and only one table per area and indexes in separate area.
This is the baseline number to compare future Scatter Index measurements.
A value of 1 indicates that the records occupy completely contiguous database blocks.
A value higher than one indicates that the records are scattered more than 1 block apart on average.
Use this value to determine the performance impact caused by the distance between records of the same table (scatter).
If the value is 1.5 or greater, performance will be less than ideal for sequential record operations (reports, batch updates, etc.) can suffer. Dumping and loading the data might be warranted.
A value of 1.5 or greater might also reduce performance for random access operations; however, this depends on the system type and the application.
To minimize the growth of the scatter factor on table(s) that are highly write intensive (creates/updates/deletes) consider moving all the records of that table to a dedicated area; the indexes should also be in an area separate from the data.
Consider Type II Storage Areas with either a single tables or multiple tables for lower scatter factor.
The architecture of Type II areas inherently reduces scatter.
While a single table in a Type II area is the optimum, the design of Type II areas make scatter much reduced even for multiple tables or tables and indices.
Use "prostrct add <db> [file.st]" to add a new area.
Use "proutil <db> -C tablemove <records_area> <indexes_area>" to move the table to its own area.
