[Users] using aliases or dbaliases

[unplug]

What is the difference between using table of aliases & dbaliases?  As
I know, openser will load the records in aliases to memory when it
starts.  There is a problem when the aliases table contains over
15,000 records and openser will fail to start due to the memory
problem.  As search from the module document, dbaliases can be used to
replace aliases.  The records in dbaliases store in DB instead of
memory when openser starts.  Everytime, openser will query the DB for
the alias of an account.  Am I right?