[imp] Trouble with downloading large attachments

[Rick Irvine]

System: Redhat 7.3
Horde: cvs RELENG  (and 1.x)
Imp: cvs RELENG (and 2.x)

I'm having trouble with downloading large (2-15+ meg) attachments.  I'm
still debugging, but I wanted to share my obvservations and see if anyone
has come across this as well.

If the attachment is fairly small, it works.  I have tested many small
(5k-200k) attachments and they work fine.  But, if the attachment is of
signifigant size (2-15 megs), the apache process never seems to come back.
I can watch the imapd processs on the imap server and see that it is indeed
downloading the attachment, however this happens without the client side
download window popping up.

I noticed on a 2 meg attachment that the client download window did not appear
until the attachment is already completely downloaded from the imap server.
On the 15 meg attachment, the apache process never seems to come back after
the imapd completes the download.  I have already set several php.ini settings
much farther up, including max memory, script execution time,
upload_max_filesize, etc.  I have also tested this with an attachment of the
same size with no spaces in the name, same behavior.

Now, on the old horde/imp installation, this same attachment download attempt
on the same message brings up the client download window immediately.  BTW, I
am not using IE for this, I am using Mozilla (so no IE issues to get in
the way).

The next step for me is to make the httpd run as a single process and strace
it to see what it does after it gets the full attachment.  But logic would
say that it should be bringing the client side download window up immediately
and before it actually starts downloading the attachment from the imapd,
shouldn't it?

I also just tested this this morning on a socket horde/imp with nothing
else, and am noticing the same behavior.  So my guess is either it's in the
RELENG packages or it's in my php configuration.  But nothing in my php.ini
seems to leap out at me and say "hey I'm the reason your download windows
are not showing up!".

Any thoughts would be greatly appreciated.

Thanks!

- Rick Irvine