Re: [exim] Local senders whitelist: practical limits

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Συντάκτης: Heiko Schlittermann
Ημερομηνία:  
Προς: exim-users
Αντικείμενο: Re: [exim] Local senders whitelist: practical limits
W B Hacker <wbh@???> (Do 25 Jan 2007 22:27:54 CET):
> Rob Munsch wrote:
> > Hello list.
> >
> > Due to increasingly fascist local antispam policies, we are of course
> > bouncing a lot of people's mail. Such people are invariably the friends
> > and/or business contacts of Important People in the office.
> >
> > I'm using an
> >
> >    accept
> >      senders = lsearch*@;/etc/exim4/local_whitelist

> >
> > before my ACLs start getting nasty, which a flat file containing the
> > addresses of People Who Should Never Be Blocked. But naturally now that
> > the existance of this file is known, everyone wants in on it. One
> > enterprising department forwarded me a spreadsheet of 2000 addresses
> > "who we never want to get bounces," most of them from @gmail.
> >
> > So:
> >
> > 1) How large can this local_whitelist get before i start doing Horrible
> > Things to my server's performance?
>
> With most modern CPU, MB, memory, HDD, and file systems, probably well into
> tens of thousands of entries. Even then not 'horrible' - just not optimal.


citing my self:


>From hs@??? Mon Jan 1 20:07:07 2007

Date: Mon, 1 Jan 2007 20:07:07 +0100
From: Heiko Schlittermann <hs@???>
To: exim-users@???
Subject: Re: [exim] [follow-up?] Re: Performance of MySQL vs text files.

....

First, time for exim startup:

    # time exim4 -bV >/dev/null
    real    0m0.032s
    user    0m0.020s
    sys     0m0.010s


Now, flat file (about 5000 lines)
    # time exim4 -be '${lookup{217.72.192.234}lsearch{/tmp/seen.txt}}'


    # looking up the first entry in this file:
    real    0m0.031s
    user    0m0.030s
    sys     0m0.000s


    # looking up the very last entry in this file:
    real    0m0.036s
    user    0m0.020s
    sys     0m0.020s


Now, same with DBM (about 5000 entries)
    # time exim4 -be '${lookup{217.72.192.234}dbm{/tmp/seen.db}}'
    # (there's no difference between the last and the first
    # entry, as expected)
    real    0m0.032s
    user    0m0.030s
    sys     0m0.000s


And now using sqlite
    # time exim4 -be '${lookup sqlite{/tmp/seen.sql SELECT * FROM seen WHERE item = "217.72.192.234"}}
    real    0m0.033s
    user    0m0.030s
    sys     0m0.000s


And finally mysql (using local unix socket)
    # time exim4 -be '${lookup mysql{SELECT * FROM seen WHERE item = "217.72.192.234"}}
    real    0m0.034s
    user    0m0.010s
    sys     0m0.020s


Until here we do not see some significant difference, but it should be
expected that DBM and SQLite/MySQL will scale better than the flat file.

(For getting more significant data and to eleminate the time exim loads itself I'd
create a small perl "plugin" executing several hundreds of lookups via Exim::expand_string().)

....

    Best regards from Dresden
    Viele Grüße aus Dresden
    Heiko Schlittermann
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