Solr commit and optimize: which user?

Hi,

I have Solr FTR working with dovecot, and need to do the commit and optimize recommended here: https://wiki.dovecot.org/Plugins/FTS/Solr

Should this run as root, or as each mail user. The documentation above implies, but doesn't state, that it is root. The docs here are similar: http://grimore.org/networking/dovecot/full_text_search

But the docs here say it has to be done for each user: http://www.unixsamurai.com/dovecot-full-text-search-jetty-solr/

I don't know Solr well enough to answer. Which is correct?

Thanks

John