[Dovecot] Performance, dovecot vs tpop3d

[Joseph Tam]

>> 2.  logout, log back in immediatly, there is no re-indexing and the
>> list is available in < 1 second.
>> 3.  logout, log back in 12 minutes later.  The list is returned in
>> apx 15 seconds and again in a lsof I see pop3 accessing files inside
>> the cur/ directory.
...
>
> Of added note, when running a stat on the index files (dovecot.index,
> dovecot.index.cache, dovecot.index.log), the Modify and Change
> parameters remain static (no changes).  So if it's rebuilding
> anything it's doing it in memory and not modifying the index files.
>
> If I deliver a new message to the account, it does rebuild the files
> for sure and increments the Modify and Change params.

Perhaps what you might be seeing is file system caching.  I notice this
when performing NFS I/O tests: the first re-read is fast but decays
over time as data is rolled out of the cache.

Joseph Tam <tam at math.ubc.ca>