On Wed, 2009-03-04 at 19:30 -0500, Timo Sirainen wrote:
http://dovecot.org/patches/1.1/maildir-dirty-syncs.diff .. I'd be interested in hearing how large performance benefits it gives, if any.
Anyone?
I did a couple of small unrealistic tests with imaptest. With small mailboxes it shows no difference. With larger mailboxes it seemed to be about 25% faster:
N=old behavior, Y=dirty syncs
imaptest logout=0 secs=30 logout=0 msgs=1000 delete=10 expunge=10
Logi List Stat Sele Fetc Fet2 Stor Dele Expu Appe Logo
100% 50% 50% 100% 100% 100% 50% 10% 10% 100% 10%
30% 5%
N: 10 2122 2112 10 4146 5947 2045 334 411 2344
Y: 10 2911 2899 10 5761 8194 2758 444 578 3629
imaptest logout=0 secs=30 logout=0 msgs=10000 delete=10 expunge=10
Logi List Stat Sele Fetc Fet2 Stor Dele Expu Appe Logo
100% 50% 50% 100% 100% 100% 50% 10% 10% 100% 10%
30% 5%
N: 10 1553 1555 10 3129 4514 1548 245 336 3132 --> 2717 msgs in maildir
Y: 10 2157 2109 10 4189 6053 2035 310 441 4190 --> 3673 msgs in maildir
Although if the clients are disconnecting often, there's not much of an improvement:
imaptest box=lols logout=0 secs=30 logout=10 msgs=1000 delete=10 expunge=10
Logi List Stat Sele Fetc Fet2 Stor Dele Expu Appe Logo
100% 50% 50% 100% 100% 100% 50% 10% 10% 100% 10%
30% 5%
N: 502 2779 2837 502 5627 7996 2776 455 604 2411 1004
Y: 593 2909 2975 593 5892 8526 2895 467 559 2491 1186