On Fri, 17 Dec 2004, Peter Stuge wrote: >On Thu, Dec 16, 2004 at 11:32:06PM +0100, Andreas Aardal Hanssen wrote: >> PS: And yes, I know it's been mentioned before, but the perfect mailbox >> format has yet to be discovered. For example, one that allows snappy >> access even with 300000 messages, one that allows setting of flags >> without race conditions (such as the renaming in Maildir, which is >> very inefficient with big mailboxes with many accessors, such as a >> shared mailing list), one that allows moving, adding and deleting >> messages fast, and in a crash-safe way. One that deals with modern >> principles such as indexing, shared mailboxes and high concurrency. >> That would be something. :) >Sounds a lot like an indexed SQL server.. >Does anyone on the list have experience from mail stored e.g. in >MySQL?
No database that I know can handle the extreme amount of email arriving to an email hub of a decent size. Even the most industry standard email hubs use specialized storage to speed things up. The speed of direct access compared to the latency of accessing a SQL server is very significant. And the disk space and memory requirements of huge databases are huge. I used to work at such an email hub, and at peeks it pumped over a million emails per mail exchanger every day, and we had twelve of them. We stored 1.2 terrabyte of email data, in about one 1 billion (1024*1024*1024) emails. Our mailbox format was maildir, the mail server was qmail. Now if someone can come up with a database that can store random data of sizes varying from 512 bytes to several megabytes, at 10-15 arrivals a second, I'd be willing to change my opinion. ;) Andy :-) -- Andreas Aardal Hanssen | http://www.andreas.hanssen.name/gpg Author of Binc IMAP | "It is better not to do something http://www.bincimap.org/ | than to do it poorly."
