lmtpd: deliver.db checkpointing

[Eric Luyten]

On Mon, November 15, 2010 3:46 pm, Patrick Boutilier wrote:
> On 11/15/2010 10:36 AM, David Mayo wrote:

>> On our setup, the checkpoint runs every couple of days and usually takes
>> 4-6 minutes[1]. We run cyr_expire every night to remove entries older
>> than 3 days from the duplicate deliveries database but this is the only
>> maintenance we can schedule on this database.
>
>
> No solution, but I wonder why your checkpoint takes so long? With
> similar DB size it take only seconds here.
>
>
>
> Nov  8 21:18:04 student2 lmtpunix[6541]: skiplist: checkpointed
> /var/imap/deliver.db (650493 records, 67180160 bytes) in 5 seconds
>
>
> Nov 12 23:14:06 student2 lmtpunix[26425]: skiplist: checkpointed
> /var/imap/deliver.db (768262 records, 80010936 bytes) in 11 seconds
>


Hmm. We're running Cyrus 2.3.16 on a SunFire X4170 (dual quad core
Xeon at 2.8 GHz, Cyrus databases are Skiplist and located on Solid
State Disk) and I noticed :


(Fri) Nov 12 13:32:20 mcs1 lmtp[2558]: skiplist: checkpointed
/ssd/cyrs/imap/deliver.db (185106 records, 19039404 bytes) in 32 seconds

(Sat) No deliver.db checkpointed by our LMTP.

(Sun) Nov 14 06:56:07 mcs1 lmtp[7737]: skiplist: checkpointed
/ssd/cyrs/imap/deliver.db (74285 records, 7511272 bytes) in 2 seconds

(Mon) Nov 15 11:18:08 mcs1 lmtp[23084]: skiplist: checkpointed
/ssd/cyrs/imap/deliver.db (141624 records, 14532184 bytes) in 55 seconds


My first impression is that elapsed checkpointing time is tied
to server activity (but not necessarily CPU load, since our system
is very lightly stressed throughout the day, in that respect).


Eric Luyten.