hardcommit setting in solrconfig

[Joshi, Shital]

Hello,

We have following hard commit setting in solrconfig.xml.

<updateHandler class="solr.DirectUpdateHandler2">
    <updateLog>
      <str name="dir">${solr.ulog.dir:}</str>
    </updateLog>

     <autoCommit>
       <maxTime>${solr.autoCommit.maxTime:600000}</maxTime>
       <maxDocs>100000</maxDocs>
       <openSearcher>true</openSearcher>
     </autoCommit>
  </updateHandler>

Shouldn't we see DirectUpdateHandler2; start commit  and DirectUpdateHandler2; 
end_commit_flush message in our log at least every ten minutes? I understand 
that if we have more than 100K documents to commit, hard commit could happen 
earlier than 10 minutes. But we see hard commit spaced out by more than 20 to 
30 minutes and sometimes couple hours. Can you please explain this behavior?

Thanks!