[Dovecot] using dsync to convert mailboxes looses caching options

[Mark Zealey]

OK I'll test the header copying more fully. The reason we want to preserve caching decisions is to avoid an IO storm when users log in to their mailboxes after an sdbox upgrade so it would be great to be able to have some way to warm caches.

Mark
________________________________________
From: Timo Sirainen [tss at iki.fi]
Sent: 08 December 2011 09:27
To: Mark Zealey
Cc: Dovecot Mailing List
Subject: RE: [Dovecot] using dsync to convert mailboxes looses caching options

On Thu, 2011-12-08 at 09:19 +0000, Mark Zealey wrote:
> OK now it's copying the timestamp fields for tmp ones. However:
>
> 1) hdr.* fields are not being copied at all (unlike in previous releases)

They are in my tests.. This also happens if the destination doesn't
exist?

> 2) although the decisions are now being recorded; the items are not actually being put into the cache for previously sync'd mails. New mails are having all the cache information produced however.

This is intentional. Doing anything else would be horribly inefficient.
Note that dsync isn't *copying* cached data. It's simply setting the
caching decisions, and the mail saving code parses the mails and updates
cache.

> Perhaps this should be activated by a new option to dsync; if people are using this for backup (rather than conversion) caches could get relatively large?

Hm. Maybe..