[Dovecot] Using MySQL to store email?

[Steffen Kaiser]

On Tue, 6 Jun 2006, Lev Serebryakov wrote:

>  Best solution seems to store e-mails as-is, one e-mail per file, and 
> store some indexes in simple low-level database, like BerkeleyDB. 
> Filesystem does best in working with "BLOBS" and simple database engine 
> without complex query langauge allows to have VERY fast indexes.

I have nothing but trouble using OpenLDAP's fast BerkleyDB implementation.
I agree that BLOBs in a filesystem are much faster than the overhead 
required to pull it from a DB, esp. because you can sent the data right to 
the client. (I don't know if you can instruct a DB to send BLOBs right 
into a TCP channel).

However, when it comes to discussion to take a message apart and store its 
parts sharing them, it would be a matter of benchmarking: Can you still 
read the part from the filesystem and pass it forth directly?

I also don't believe that SQL is a complex language per se, because it 
offers complex and slow stuff; there has been a pletoria of high- and 
low-grade programmers, engineers and theoreticers, who built good 
algorithms and optimization strategies for SQL, nobody can re-implement 
easily.

I also guess that it would make no sense for Dovecot to utilize both 
backends, I mean: if you go the SQL way half-heartedly, it worse and 
nobody will use it happily, but then you will loose focus for the 
filesystem based storage and lots of people don't want to install a DB.
There is a discussion about this very same topic in OpenLDAP: Summary 
(view of mine :): the SQL backend is lots quicker, but OpenLDAP's useage 
of it is bad, because written for BerkleyDB, that the performance is 
lower; one needs to rewrite to much code and afterwards the SQL DB is 
quick, but BDB slow.

>   This solution has one additional advantage: all indexes can be rebuild 
> by e-mails, if DB is backed up with errors, for example.

IMO: This is one thing, that needs to be done for Dovecot, e.g. keywords, 
and a toolset.

-- 
Steffen Kaiser