How to trigger the XMLTV EPG grabber ? (opens in new tab)

Hello, I have configured DVB-T channels with OTA EPG data, it works fine\. I have configured an external EPG grabber to write XMLTV data into tvheadend's XMLTV\.sock\. This populates the Grabber channels and my channels are correctly associated there\. However \.\.\. it usually takes a about a day for the XMLTV data to show up in the EPG after I configure it\. The old OTA data keeps being shown for a while\. I don't know what triggers this refresh\. Is it possible to trigger it manually ? I'v...