More Skiplist Stuff!

[David Carter]

On Fri, 11 Jan 2008, Bron Gondwana wrote:

> The better alternative to this patch would be to rewrite the fast_rename
> and folder_limit patches to not do untransactioned reads in the middle
> of a transaction, but that involves API changes to a few functions so
> that the transaction will be passed around.

fast_rename doesn't seem to do this: the two mboxlist_count_inferiors() 
calls fall between a DB->commit and the following DB->delete and 
DB->store. I guess this is why I haven't been having problems. Phew.

folder_limit does have a problem as mboxlist_mycreatemailboxcheck() is 
used in the middle of a transaction in mboxlist_renamemailbox(), maybe 
other places as well. I think that my approach would be to move the folder 
limit test into imapd.c, cmd_create(). I think that's the only place where 
end users can create new mailboxes without one of the autocreate patches.

> Either that or just create a global "struct txn *mailboxesdb_txn" or 
> something and use that. Pretty icky either way, but at least it won't 
> break on berkeley mailboxes_db.

Does the Berkeley backend deadlock if you start an DB->foreach in the 
middle of a transaction? That would be a pain. I did like your idea of 
reusing the existing transaction/lock if the caller didn't specify one.

-- 
David Carter                             Email: David.Carter at ucs.cam.ac.uk
University Computing Service,            Phone: (01223) 334502
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