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List:       exim-users
Subject:    Re: [exim] spammers IP ban
From:       David Saez Padros <david () ols ! es>
Date:       2006-02-28 9:05:48
Message-ID: 4404126C.6030208 () ols ! es
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Hi !!

>>is faster to directly write to mysql instead of parsing the log,
>>specially if the log file is very big,
> 
> Exim writing to the log has no incremental overhead at all - unless
> you've turned off logging for some reason. However fast a MySQL INSERT
> is, it's slower than doing nothing extra at all.

but then you have to parse the log, which takes some time (our log
file is really very very big) and then you have to do something with
the extracted data, in the case Mathieu comments he just ... well
he just insert that data on a mysql database ... so he adds extra
lines to the log, then it has to parse the log, extract the data
and insert in into a mysql database. The only optimization he could
do is make only one insert with all data but i don't think this will
be really more faster than just doing delayed inserts from within exim

>>the mysql connection is
>>done to localhost so there are no connection problems (you can
>>also use delayed inserts to speed up things).
> 
> While MySQL is up, agreed. My point was the unpredictable situation
> when it isn't.

i've been running mysql for years without such problem, anyway in the
worse case you will only prevent some host to be blacklisted but in
real world that host will try again to send spam/virus to you so they
will end being blacklisted anyway.

> Absolutley - my logscraper (which picks up new log entries sub-second)
> writes to MySQL for exactly these reasons. But it does it without
> impacting the mail delivery flow.

in our case, a delayed insert every 3 seconds does not impact the mail
delivery flow in any measurable amount of time, in fact it would be
possible to do many inserts per second before the mail flow could be
delayed in a measurable amount of time.

> Exim doesn't parse any of these for me - the MySQL database is used to
> generate a config file for rbldnsd; Exim queries the private rbldnsd
> zone which is really quick, and you can control Exim's behaviour
> should the rbldnsd daemon be unavailable for some reason.

if you want speed a local cdb file is faster than drbldns

-- 
Best regards ...

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