Solr FTS - when does indexing happen?

[Shawn Heisey]

I have Solr FTS on my dovecot install.  I followed the instructions on 
the dovecot wiki.

How long a delay should I expect to see between new mail being delivered 
with the dovecot LDA and an indexing request sent to Solr?  Because I 
get a LOT of email from various mailing lists, and I do not see any 
activity in Solr's log.  When I did doveadm index -A -q '*' there was a 
lot of indexing activity in Solr's log, as expected.

One time I looked at the Solr index and it had been 23 hours since it's 
last update ... I can guarantee that I received a lot of new messages in 
that time.

What do I need to look at for further troubleshooting?

I can confirm that when I issue a search in the TypeApp app on my phone 
(an IMAP app for android), I see the query in Solr's logfile.

Thanks,
Shawn