[Dovecot] Duplicate Attachments....

[Tore André Klock]

Timo Sirainen wrote:
> I think that could anyway be a good idea, but how about hash collisions?
> I could just ignore that since they would practically never happen. Hash
> + attachment size would be even safer. The only truly safe way would be
> to read the whole attachment from disk and compare it byte-by-byte, but
> that'd just slow it down unneededly.. Perhaps it should be an option.
Collisions won't be a big problem if you use something like SHA, but it would be
slow.  You have to generate a checksum for both sides of the comparison, meaning
you have to generate it at least once per message.  Generating it always means
reading every byte of it.

A better solution might be for the LDA to detect which messages are being
delivered locally to more than one user.  I could then make the message file
shared (in the case of Maildir anyway), for example by hard-linking the files.
The message would then exist on disk in one copy until each client have removed
it (bringing the link count to 0).

Just an idea.

- Tore