I have not tried modrdn.
Very early in my testing I thought I was seeing unbounded
growth by performing endless deletes (and re-adds). That, I
found out through your much-appreciated responses to this list,
was causing an explosion in tombstone entries and thus the
server was exploding in actual data requirements.
We don't actually place much importance on that use case
because we hardly ever delete an entry, so the housekeeping
process for tombstones is more than ample for that cleanup.
The ldapmodify use case is critical to us however, because we
perform large quantities of ldapmodify operations every day.
This memory growth situation I have described here applies
specifically and only to endless ldapmodify operations.