http://dovecot.org/patches/1.1/maildir-dirty-syncs.diff This patch adds a new maildir_very_dirty_syncs setting. If set to "yes", Dovecot assumes it's the only one changing the cur/ directory (so other MDAs can add mails to new/ without problems). This makes it possible to avoid rescanning the cur/ directory all the time looking for filenames. It also looks like (in stress testing) it still scans the cur/ directory unneededly in some situations, but it shouldn't be common. Maybe I'll look into it some day to see why. I'd be interested in hearing how large performance benefits it gives, if any. If they're big I could consider adding it to v1.1.12. If they're pretty much irrelevant I probably won't even bother adding the code to v1.2. I guess you mainly see the performance benefits with large/huge mailboxes. -------------- next part -------------- A non-text attachment was scrubbed... Name: signature.asc Type: application/pgp-signature Size: 197 bytes Desc: This is a digitally signed message part URL: <http://dovecot.org/pipermail/dovecot/attachments/20090304/642cf18c/attachment-0002.bin>
Le Wed, 04 Mar 2009 19:30:45 -0500 Timo Sirainen <tss at iki.fi> ?crit:> http://dovecot.org/patches/1.1/maildir-dirty-syncs.diff > > This patch adds a new maildir_very_dirty_syncs setting. If set to "yes", > Dovecot assumes it's the only one changing the cur/ directory (so other > MDAs can add mails to new/ without problems). This makes it possible to > avoid rescanning the cur/ directory all the time looking for filenames. > It also looks like (in stress testing) it still scans the cur/ directory > unneededly in some situations, but it shouldn't be common. Maybe I'll > look into it some day to see why.Hi, does it means that if I only use dovecot to read the maidir (pop3 or imap), I can use this setting ? Or does it mean that if there is always only one dovecot process reading the maildir, I can use this setting ? What happens if I use this setting and I read the mailbox from 2 different webmail ? -- Laurent Papier - 03 88 75 80 50 Admin. syst?me - SdV Plurimedia - <http://www.sdv.fr/>
> Dovecot assumes it's the only one changing the cur/ directoryDoes this mean "there's no program that's not dovecot accesssing cur" or "there's no other process than this dovecot accessing cur"? I.e., what about two dovecots on two servers with Maildirs on NFS?
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 -------------- next part -------------- A non-text attachment was scrubbed... Name: signature.asc Type: application/pgp-signature Size: 197 bytes Desc: This is a digitally signed message part URL: <http://dovecot.org/pipermail/dovecot/attachments/20090313/4799934c/attachment-0002.bin>