[MlMt] MailMate so slow it locks up

[Alex Bligh]

I'm having great difficulty moving from Mail.app & Thunderbird to MailMate, because MailMate is so so slow it locks up.

Here's the background. I am currently using Mail.app and Thunderbind to access a couple of IMAP accounts. The IMAP accounts are LARGE. The smaller one has I think 200,000 - 300,000 messages in it, and the large one probably five times that (1,000,000 - 1,500,000). I am on a high powered Mac Pro with SSD disks running El Capitan, lots of CPU, lots of RAM and lots of bandwidth. Mail.app and Thunderbird work fine. Because Mail.app does not support IMAP subscriptions (and I don't want all 1m+ messages on the SSD syncing all the time) I have a homebrewed IMAP filter between Mail.app and my server (so this isn't a strictly fair comparison for Mail.app), but Thunderbird accesses both accounts directly in the normal way.

On installing MailMate, I set up the smaller account first (300,000 messages). It correctly imported the settings, but after that there was a world of pain. It sync'd all the mail, but only by running 2 CPU cores at 100% continuously for over 24 hours. Neither Mail.app nor Thunderbird do this; they import in the background, and (for that mail account) take only a few hours. Saying that, after 24 hours (perhaps a bit more), it had pulled all the mail in and appeared to work.

I then enabled the larger account. On enabling it, CPU pretty much immediately skyrocketed. Eventually I managed to get to the subscriptions panel and activate the setting that restricted subscriptions to the mailboxes subscribed on the server (which would have totalled maybe 400,000 messages maximum), but to no avail, CPU still pegged at 2 x 100%. I quit MailMate, and restarted. I didn't even see a UI for an hour (solid beach ball), and after that left it for 48 hrs, by which time the process size had grown to 8GB. MailMate was fantastically unresponsive during this time - clearly importing is a real CPU and memory hog.

At this point I gave up for the time being.

The mail server is running cyrus imapd 2.4, has many users on it, and not one of them has seen any problems with any other MUA to my knowledge. I regularly use Mail.app, Thunderbird (on OS-X) an iPhone, and until a couple of years ago Mulberry, with no issues. I know others are running all sorts of stuff (so imap logs tell me). The problem is not the mail server, and it's certainly not the client - Thunderbird is pretty fast, and Mail.app is positively zippy.

In the brief time I used MailMate on the smaller account, I really liked it. But even if I could get over the import issue, the fact that if I ever lose my mail spool I'd need to last 48 hours+ without a mail client that works is a red flag for me.

Any ideas what this might be and/or how to fix it?

-- 
Alex Bligh