For btree tables, the leaffill parameter specifies to the DBMS Server how full to fill the leaf index pages. Leaf index pages are the index pages that are directly above the data pages. Nonleaffill specifies how full to fill the non-leaf index pages. Non-leaf index pages are the pages above the leaf pages. Specify leaffill and nonleaffill as percentages. For example, if you modify a table to btree, specifying nonleaffill=75, each non-leaf index page is 75% full when the modification is complete.

The leaffill and nonleaffill parameters can assist you in controlling locking contention in btree index pages. If you retain some open space on these pages, concurrent users can access the btree with less likelihood of contention while their queries descend the index tree. You must strike a balance between preserving space in index pages and creating a greater number of index pages; more levels of index pages require more I/O to locate a data row.

Default values for leaffill and nonleaffill are 70% and 80%, respectively.