startup process that rebuilds aliases.db?

[Robert Moskowitz]

My system does not have a battery for the clock (like most armv7 SOCs), 
thus I rely on that at some point in boot time, chronyd sets the time.  
If a file is updated prior to chronyd accomplishing its task (or network 
connectivity is down), the file ends up with a timestamp of "Dec 31  1969".

I notice that occasionally, after a reboot, /etc/aliases.db reverts to 
this time, and I have to run newaliases to fix it.  I suppose I could 
run touch as well.

So is postfix startup rebuilding aliases.db, perhaps?  Is there some way 
to delay postfix startup until after chronyd, or some other method to 
keep the date for aliases.db stable?

Note that aliases.db does not always revert to this date after startup, 
implying whatever is doing this either sometimes manages to run after 
chronyd, or not on every reboot.

thanks