Short Description: Specifies a default lifetime for indexes associated with database views.
Allows administrators to set a default lifetime for indexes associated with database views if none was selected by the database designer in the Design View Attributes dialog box ("Discard index on server after n days of inactivity"). Normaly indexes will not be discarded unless they have not been accessed. Without this setting in the NOTES.INI file, the default index lifetime is 45 days. Specifying a default index lifetime is a spacesaving feature since the index associated with the view is automatically purged when the index is inactive for the specified number of days. The Indexer server program handles this task.
Default_Index_Lifetime_Days=number of days
There is no kown UI setting for this notes.ini variable. But you can specify this setting in the notes.ini settings tab of the configuration settings document.
What causes Notes database indexes to rebuild?