long delay in getting lock on 2.4.16

Bron Gondwana brong at fastmail.fm
Wed Nov 14 07:51:03 EST 2012


On Wed, Nov 14, 2012, at 12:53 PM, Deniss wrote:
> hello !
> 
> I have an issue with cyrus-imapd-2.4.16 and locks.
> cmdtimer reports long time execution like this:
> 
> Nov 14 08:47:15 brat5 imap[16897]: cmdtimer: 'ega9024' 'status' '<none>' 
> '24.577343' '0.000000'
> Nov 14 10:18:02 brat5 imap[26631]: cmdtimer: 'evijanagle' 'select' 
> 'user.evijanagle.Photos' '24.136381' '0.000000'
> Nov 14 10:18:02 brat5 imap[26622]: cmdtimer: 'evijanagle' 'select' 
> 'user.evijanagle.Photos' '31.103348' '0.000000'
> Nov 14 10:58:32 brat5 imap[30646]: cmdtimer: 'egil^k' 'status' '<none>' 
> '22.480196' '0.000000'
> Nov 14 10:58:32 brat5 imap[30708]: cmdtimer: 'egil^k' 'status' '<none>' 
> '10.285937' '0.000000'
> 
> i traced down to func mailbox_lock_index() where following code produces 
> delays:
> 
>      if (locktype == LOCK_EXCLUSIVE)
>          r = lock_blocking(mailbox->index_fd);
>      else
>          r = lock_shared(mailbox->index_fd);
> 
> lock files are stored in tmpfs
> 
> 
> what is the problem may be here ?

Smells like cyr_expire is running.  Do you get cyr_expire log entries around
the same time?  It needs an exclusive lock while it repacks the index, so you
should notice that the mailbox was being repacked, and these other programs
had to wait until the lock was freed before they could open the mailbox.

This would be caused by having quite high IO wait times (or very large folders)
for those users.

Bron.
-- 
  Bron Gondwana
  brong at fastmail.fm



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