[exim] What do these commands do, what are their effects to …

Hi,

i'm newbie with exim and experienced a problem with some messages that
were not send. In exim main logs i saw this error for the messages:
R=lookuphost T=remote_smtp defer (-53): retry time not reached for any
host

As i read and checked in the net, this can happen because rejected
connections from the remot stmp server, then system retry sending of
messages. Also can be caused from corrupted exim database.

I read in the net for this solution:

/usr/sbin/exim_tidydb -t 1d /var/spool/exim retry > /dev/null
/usr/sbin/exim_tidydb -t 1d /var/spool/exim reject > /dev/null
/usr/sbin/exim_tidydb -t 1d /var/spool/exim wait-remote_smtp > /dev/null

/scripts/courierup -- force
/scripts/eximup --force

Can you tell me what the first 3 commands do and what are their effects
to the messages in queue and the messages that gets this error message?

Are there any bad effects to use these commands - messages to be lost,
messages to be removed from queue or something similar?

I'm sorry for my bad english ;)

Thanks in advanced!