They sent more than 20,000 invitations, it was on IRCC website. IRCC will process all up to June 28 received applications.This isn't true. They only sent 20,000 invitations. and ater reviweing the files, if they don't have full 20,000 applications then they will ask more people to apply based on that.
http://www.cic.gc.ca/english/helpcentre/answer.asp?qnum=1486&top=14