Understood,
But now one question, now i have in dbmail.conf SHA1, can i change now for
"SHA1,TIGER"? I mean, the emails that were inserted with SHA1 there's no 
problem?



-----Original Message-----
From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On Behalf
Of Paul J Stevens
Sent: segunda-feira, 11 de Fevereiro de 2008 7:33
To: DBMail mailinglist
Subject: Re: [Dbmail] Hash algorithm

You can use any of the supported hash algorithms. It doesn't *really*
matter which one you choose as long as the hash field is wide enough to
contain it. It is a matter of balance and trade-off.

During message insertion the hash is used to quickly locate mime blobs
with the same hash signature. The blobs located are then compared
byte-by-byte (memcmp) to make sure it is the exact same one as the one
we're inserting, and only then do we skip inserting this blob again.

If you use a short hash, like md5, the chances of hash-collisions are
much higher, and dbmail will have to examine more blobs byte-by-byte.
So for short hashes dbmail will (probably) take longer to investigate
more blobs, but short hashes will (probably) be located faster by the
database index-scanner. I suspect it is a trade-off, but I don't know!
It most likely depends on the size of your storage and the database backend.

I would advise you to stay away from the really long hashes since I'm
pretty sure the index will become too large and expensive.

SHA1 or TIGER are excellent hashes for the purpose at hand.

Jorge Bastos wrote:
> Ops
> 
> Ignore this, i forgot to restart the server!!!
> 
>  
> 
>  
> 
> *From:* [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] *On
> Behalf Of *Jorge Bastos
> *Sent:* domingo, 10 de Fevereiro de 2008 22:35
> *To:* DBMail mailinglist
> *Subject:* Re: [Dbmail] Hash algorithm
> 
>  
> 
> I'm having this:
> 
>  
> 
> Feb 10 22:31:13 lira dbmail/lmtpd[32337]: Warning:[misc]
> dm_misc.c,dm_get_hash_for_string(+2395): hash algorithm not supported.
> Using SHA1.
> 
>  
> 
> What should i do?
> 
> I have in dbmail.conf:
> 
>  
> 
> hash_algorithm = SHA1
> 
>  
> 
>  
> 
>     ----- Original Message -----
> 
>     *From:* Jorge Bastos <mailto:[EMAIL PROTECTED]>
> 
>     *To:* DBMail mailinglist <mailto:[email protected]>
> 
>     *Sent:* Sunday, February 10, 2008 10:06 PM
> 
>     *Subject:* [Dbmail] Hash algorithm
> 
>      
> 
>     Hi,
> 
>      
> 
>     For 2.3x, wich Hash Algorithm should i use?
> 
>     SHA1/SHA256/TIGER?
> 
>      
> 
>     Jorge
> 
>
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> 
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-- 
  ________________________________________________________________
  Paul Stevens                                      paul at nfg.nl
  NET FACILITIES GROUP                     GPG/PGP: 1024D/11F8CD31
  The Netherlands________________________________http://www.nfg.nl
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