[Dovecot] new configure-option --disable-index

[Curtis Maloney]

Marten Lehmann wrote:
> Dovecot is really fine, but it still isn't NFS ready. Especially when 
> using dovecot as pop3 only this index-stuff must be disengageable. What 
> is the use of generating a complex index file for hundreds of messages, 
> that will be deleted in the next step after downloading them?

Well, part of the issue is that Dovecot is _primarily_ an IMAP server, where 
these indexes prove invaluable to its performance.  The POP3 side is more of an 
added bonus.

> But the index is also a problem when using IMAP over NFS.

This is why you can configure Dovecot to use indexes on the local disk, or in 
memory, as I believe someone else has already mentioned.

 > Access to the files is
> too slow, so the connections keep hanging around and the i/o waiting 
> value is raised to a maximum which slows down the whole machine. It 
> simply doesn't make sense to build and update an index every time the 
> maildir is accessed (which is very cpu and timeconsuming), while search 
> operations (the only moment when the index is actually used and not just 
> heavily updated) don't affect even 1% of all IMAP calls (and such a 
> command doesn't even exist for pop3).

I was fairly sure Timo has the index doing more than what you'd at first expect.

> 
> I would be much obliged if you could create an option called 
> "--disable-index" in the configure-script or something like 
> "disable-index = yes" in dovecot.conf that makes dovecot ignoring 
> existing index files and doesn't care for related operations, so NFS 
> should work much faster and IMAP search would simply parse the files 
> directly instead of looking in the index.

All that being said, I do agree that this option could well have its place.  I 
suspect Timo might even say it's possible to have a "no-index" plug-in to handle 
this.

--
Curtis Maloney
cmaloney at cardgate.net