Milter-greylist

manu@... wrote:
 > Dan Mahoney, System Admin wrote:
 > 
 > > Did the BDB version have the option to periodically (say, hourly) dump a
 > > checkpoint file or something similar?
 > 
 > The problem was that it was impossible to be sure no corruption could
 > occur on the DB file if milter-greylist crashed at a wrong time.

That's why a transactional database should be used.  It
guarantees consistency, no matter if and when the client
application crashes.

Personally I would prefer PostgreSQL which supports
transactions for ages and is rock-stable, but recent
versions of mysql also support transactions in theory
for some of its db formats.

By the way, dumping a "checkpoint" file wouldn't be a
problem at all with a reasonable database.  You would
just make an SQL export once per hour.  The client
application (milter-greylist) would not have to care
about it at all; instead a simple cron job will do.

As a nice side effect, the synchronization protocol
between multiple MX mail servers would not be needed
anymore.  They would simply access the same DB, so they
have the same data.

The processing overhead (CPU time) of the SQL queries
should be negligible, not more than the overhead of a
DNS query.

Best regards
   Oliver

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