max-journal-size does not truncate or delete the journal

[kalyanasundaram]

Hi all,
  I am using bind 9.3.4. What is the original purpose of
max-journal-size. I have mentioned it as max-journal-size 1K; at global
level and updated the zone with nsupdate with many records so the
journal size has gone more than 1K and waiting for sometime to the
journal file to get removed. It was updated in db file and journal was
not removed for a long time. Am i missing something. How long i need to
wait? 

Thanks in advance,
  -"kalyan"