branch 2.4 on prod

[Deniss]

On 25.09.2012 14:42, Adam Tauno Williams wrote:
> On Mon, 2012-09-24 at 23:05 +0200, Bron Gondwana wrote:
>> On Mon, Sep 24, 2012, at 11:30 AM, Deniss Gaplevsky wrote:
>>> hello,
>>> i have a question to Brong as main powering force of cyrus development.
>>> I know cyrus is used at fastmail/opera for serving a lot of users.
>>> But stable branch 2.4 has a lot of performance related issues - like
>>> statuscache usage, grisly index lookups, etc - fixed in 2.5 which is not
>>> stable and not available as tarballs so far.
>>> Im curious what is the cyrus branch/version in use at Fastmail/Opera
>>> currently ? How well it is compatible to cyrus 2.4 branch ?
>> We're running master + our local patches in production at FastMail.
>> You may have noticed a bunch of work last week on master - I'm pushing
>> as much time as I can into preparing for a real 2.5 release.  Even if
>> it doesn't include everything we want, we can do a 2.6 more quickly next
>> time.
>
> And more frequent, but less monumental, 'major' version jumps is nice,
> BTW.  2.3.x --> 2.4.x was a huge [and a bit scary] jump.   Slowly
> letting the awesome soak in is preferred.
>
> BTW, 2.4.x may have some warts, but performance is still much improved
> over 2.3.x; at least in my experience.

For me there was ~20% slowdown cos we was forced to enable  openssl (for 
GUID checksums) due an early bug in cyrus 2.4 with replications - 
checksuming eats some cpu

Reworked index processing in 2.4 is simpler but not optimized at all - 
full index become iterated (loaded from disk to memory) each time to 
find single record. Our problem was even worse cos c-client try to 
resolve uids to sequences in way one request to imap per uid.

Statuscache is not fully working and some time passed before we noticed

And locking issue of skiplist dbs is still here despite the code was 
improved