mdbox / selecting folder accesses hundrets of others

Coy Hile coy.hile at
Sat May 8 15:57:07 EEST 2021

> On May 8, 2021, at 7:08 AM, Florian Lohoff <f at> wrote:
> On Fri, May 07, 2021 at 06:15:55PM +0200, Florian Lohoff wrote:
>> Dovecot: 2.3.4
>> Hi,
>> i am debugging a problem where after a force-resync removed all cache
>> files (All files are 44 byte). Trying to open a folder takes literally minutes
>> (Huge mailbox - 220K folder, 45GByte compressed storage)

I don’t have an answer for you, unfortunately, as you all exercise your mail system far more thanI do.

Taking a wild guess, I’d think that having a large number of folders has potential to be more of an issue than having a large amount of mail in fewer folders. Operating under that assumption, is it possible to bound the problem? (Hypothetically say 128k folders were good, more than that and something went out to lunch or something similar.)

I am, however, watching this with interest.

Coy Hile
coy.hile at

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