antispam plugin pipe backend error when moving multiple emails

Stéphane Cottin stephane.cottin at
Mon Apr 18 12:44:37 UTC 2016


I'm bumping this because it still occurs with dovecot 2.2.22.

my dovecot-antispam plugin configuration :

   antispam_allow_append_to_spam = no
   antispam_backend = pipe
   antispam_pipe_program = /usr/bin/rspamc
   antispam_pipe_program_args = -h;;-P;********
   antispam_pipe_program_notspam_arg = learn_ham
   antispam_pipe_program_spam_arg = learn_spam
   antispam_pipe_tmpdir = /var/tmp
   antispam_spam = Junk
   antispam_trash = trash;Trash;Deleted Items;Deleted Messages

zlib enabled:
   zlib_save = gz
   zlib_save_level = 9

When moving 2 or more messages from inbox to the Junk folder:

"J47 NO [CANNOT] Failed to copy to temporary file (0.000 + 0.000 
secs).”. Command attempted: “J47 UID MOVE 106318:106319 Junk"

or sometimes

"J123 NO [CANNOT] Failed to read mail beginning (0.000 + 0.000 
secs).”. Command attempted: “J123 UID MOVE 170789:170790 Junk"

and still have the "Cached message size smaller..." in dovecot logs.

It occurs at least when header lines of an email contains Non-ASCII Text 
Batches of full ascii emails are not affected.

I can easily reproduce this from/to the Junk folder, but had unconfirmed 
reports of similar errors when batch moving mails across regular 


On 8 Nov 2015, at 11:50, Stéphane Cottin wrote:

> Hi,
> I've got some trouble with the dovecot antispam plugin and the pipe 
> backend.
> I'm using dovecot 2.2.18 with maildirs and zlib compression enabled.
> When moving 2 or more emails at once from the Junk folder to another 
> one, I always have the following error : "Failed to copy to temporary 
> file"
> In the server logs :
> imap(vvv at vvv.vvv): Error: 
> read(zlib(/data/Maildir/.test/tmp/1446974366.M123890P936.vvv)) failed: 
> Cached message size smaller than expected (13553 < 13562, box=test, 
> UID=0)
> The same operation with one email at a time, on the same emails, works 
> as expected.
> Stéphane

More information about the dovecot mailing list