Indexing Mail faster

[Marc Stürmer]

Am 27.01.2015 um 03:24 schrieb Kevin Laurie:

> Hi Thomas,
> That's very interesting.
> Below is my search result. Any idea why is my result so slow:-
> Appreciate if you could advise.

It depends on a couple of facts. Full text searches must go through a 
number of bottle necks, depending on your installation, namely:

a) type of disk drive(s),
b) way of installation of those drives,
c) the underlying file system itself,
d) the storage format being chosen to save the mails,
e) how many users you've got on your system,
f) memory of your system,
g) CPU power of your system and
h) how busy your system is.

If you got for example a lonely box with let's sax four gigs of RAM and 
you are using it by yourself only, chances are high enough that even 
with a big enough up time most of your mails are in the file system 
cache of your OS. Meaning a full text search would happen mostly in RAM 
and therefor of course would be blazingly fast.

If you take the same machine and let it serve let's say about 2000 
mailboxes, this would be a very different kind of matter. Your file 
system cache would be flushed frequently and full text searches without 
index would be way slower, because now those search actually mean I/O 
operations for Dovecot on your type of storage.

If you really want consistent, fast full text search speeds on a busy 
box, incremental full text indexing is the only way to go.

If you are the only user of a big box chances are high you get similar 
results without.