[dev] IMP performance - cache mailbox sorts

[Michael M Slusarz]

Quoting Chuck Hagenbuch <chuck at horde.org>:

> One of the biggest performance holdbacks we have in IMP is needing to
> re-sort mailboxes on every mailbox list. At least with c-client, I
> don't think there's any way to have a perfect "has the mailbox
> changed" check.
>
> So I'm wondering if we can come up with a "good enough" check. Here's
> what I'm thinking:
>
> - do an imap_status call on the mailbox. if there are "recent'
> messages, we know there's new mail we have to get

What about IMAP_Cache::?

> - deletions/purges performed by imp/dimp unset indices in the cached
> sort automatically

This should already be done in IMP_Mailbox::.

> - otherwise we save the sort for a period of time, like 30 seconds.
> not so long that changes made in other clients, etc. never show up,
> but long enough to speed up scrolling/paging through a mailbox
> quickly. this cache time is wide open for debate, of course. if Recent
> checks and updating on our own changes catch most updates, i can see
> it being more like 5 minutes.

This is definitely something proper for the config file.

> Obviously we'd check to see if the cache was still valid before doing
> the imap_status check since there's no need to run an imap_status if
> we're doing to re-sort anyway.
>
> Thoughts? Please poke holes in this if you see some, etc. Or if you're
> really inspired patches would be great. ;)

We still have to re-sort on any activity when using thread sort  
regardless of any cache time given (since a deletion in a thread sort  
can change the entire tree structure).

michael

___________________________________
Michael Slusarz [slusarz at horde.org]