T94524 introduces retention policies as a means of imposing bounds on the number of revisions maintained in a table. In light of this, some thought should be given to how the corresponding secondary index entries are handled.

Some possibilities:

1. Apply the same retention polices used on the main table, to the revisions in the secondary index
2. Drop versioning altogether, (i.e. by_attribute_ever becomes by_attribute_latest, and only a reference to the most current entry is maintained).