Comments on: What about turning on auto_vacuum on Mail’s envelope index?

By: bbum

bbum — Thu, 22 Mar 2007 03:59:02 +0000

Finding FUD tasty?

How is a feature that is turned off unless a user enables it through an unsupported / undocumented means a security hole, exactly?

And how, exactly, is a bug that might corrupt data in a user level process in exceedingly rare conditions a security hole any more than, say, simply writing a handful of bytes into a random location in the same user owned file???

In any case, I was actually wrong and have been meaning to post about this. Auto_vacuum is actually enabled under certain circumstances in Tiger. There are corruption bugs, still, but they are exceedingly rare.

By: Frog

Frog — Thu, 22 Mar 2007 03:42:27 +0000

Tiger ships with SQLite 3.1.3, which won’t be updated unless a serious security hole is found.

OK…

There have been a number of bug fixes to vacuum and vacuum related functionality since 3.1.3. In particular, there have been a handful of fixes that prevent relatively esoteric situations from corrupting a database. Some of these were directly related to auto_vacuum and some were simply catalyzed by auto_vacuum.

… so how is potential database corruption not a security hole? And we wonder why Apple hasn’t yet gotten their security act together.

By: Jon H

Jon H — Wed, 21 Mar 2007 01:57:21 +0000

Whoops, sorry, PZ’s message is at http://scienceblogs.com/pharyngula/2007/03/tech_assistance_please_help_me.php

By: Jon H

Jon H — Wed, 21 Mar 2007 01:56:46 +0000

PZ Myers of the science blog Pharyngula is having problems with Mail and a LOT of messages (100k or thereabouts, spread through a number of folders).

He tried the vacuum script, but is still having problems:

“I tried the mail vacuum script — it got the envelope file down from 77 to 66 MB. So far, no performance improvement at all. Unfortunately, it’s still also slowly cranky through flushing out the trash from that big deletion, so I’ll try again in a few hours when it’s done.
And really, that’s ridiculous. Why should it take hours to delete 10,000 messages?”

Is there some way to tell Mail “I’m going to delete a ton of messages, so don’t go fussing for every single message”?

By: aswift

aswift — Tue, 06 Mar 2007 21:45:24 +0000

Tiger’s Mail does configure the database file with auto_vacuum turned on. You can verify for yourself by running the command: sqlite3 ~/Library/Mail/Envelope\ Index “pragma auto_vacuum”
A “full” vacuum rebuilds the database file and results in a new file that is defragmented and table data is ordered on contigous pages in the database file.

By: Chris

Chris — Mon, 05 Mar 2007 18:47:00 +0000

The Envelope Index database is also polluted by “old data”. I migrated my mailserver several times and all old messages and mailboxes are still in the
database:

select count(*) from mailboxes yields a result of 350 mailboxes…

So I deleted the file (I’m one of the brave people
and restarted Mail.app. The resulting Envelope Index shrank from 18 MB (22 MB before vacuum) to 2 MB.

By: dawnfather

dawnfather — Mon, 05 Mar 2007 18:05:23 +0000

You could just set an ical event to run the script at whatever interval makes sense, e.g. the 6 months you suggest

By: bbum’s weblog-o-mat » Blog Archive » Vacuuming Mail’s Envelope Index to make Mail faster (and Aperture, too)

Sun, 04 Mar 2007 16:57:24 +0000

[...] I wouldn’t do that and I have explained why in a followup post. [...]