Plesk 11.x / Linux :: Searching Large Mailbox In Horde / Roundcube Causes Read Data Timeout

This is applies to both Horde and roundcube webmail client software;

Using Plesk 11.5.30 with Horde 5.1.5 or roundcube 0.9.5 on CentOS Linux release 6.5 (Final).

We have seen this behavior occur on multiple servers.

Clients experienced slow to no response after executing a search, which eventually results in a failed to communicate with the server-error in the webmail client.

The Apache server log shows script time-out errors when searching larger mailboxes (i.e. larger than 950 MB), this does not happen on smaller mailboxes.

We have seen errors like the following in the Apache server error log with Horde (personal data like IP-address and domain name are x'ed out):

[Thu Jun 19 14:55:06 2014] [warn] [client xx.xxx.xxx.xxx] mod_fcgid: read data timeout in 45 seconds, referer: http://webmail.xxxxxxx.com/imp/dynamic.php?page=mailbox
[Thu Jun 19 14:55:06 2014] [error] [client xx.xxx.xxx.xxx] Premature end of script headers: ajax.php, referer: http://webmail.xxxxxxx.com/imp/dynamic.php?page=mailbox

And with Roundcube:

[Tue Jun 17 13:02:04 2014] [warn] [client xx.xxx.xxx.xxx] mod_fcgid: read data timeout in 45 seconds, referer: https://webmail.xxxxxxxxxxx.com/?_t...d=19445&_mbox=INBOX&_caps=pdf=0,flash=1,tif=0
[Tue Jun 17 13:02:04 2014] [error] [client xx.xxx.xxx.xxx] Premature end of script headers: index.php, referer: https://webmail.xxxxxxxxxxx.com/?_t...d=19445&_mbox=INBOX&_caps=pdf=0,flash=1,tif=0

Steps to reproduce:

- use a large mailbox (950 MB or higher)
- login to the webmail (Horde or roundcube)
- do a search in the search field on the top right
- the time-out error should appear in the server Apache error log (after at least 45 seconds)

This seems like an inefficiency or bug in the search query that searches the user's mailbox. Is there any other way we can prevent this issue and the error messages?