conversations_expire_days and Xapian search

[Дилян Палаузов]

Hello,

I have an understanding question about searches, conversations, and Xapian in 3.0.x:

To my knowledge data (headers and body) is filled in a Xapian database.  The search with the Xapian database works
however only, if these messages are mapped in conversations_db.  There is a conversations_expire_days property with
default 90:

  How long the conversations database keeps the message tracking information needed for receiving new messages in
existing conversations, in days.

Does this mean, that by default after 90 days messages are deleted from the conversations db and cannot be found anymore
using the Xapian database?  How to setup the days, so that all messages in Xapian can be mapped to convesations_db and
therefore found?

Regards
  Дилян