fts_solr: Lookup failed: 400 Bad Request / GET null null

Chris Laif chris.laif at googlemail.com
Tue Apr 5 08:33:11 UTC 2016

On Sun, Apr 3, 2016 at 4:19 PM, Stephan Bosch <stephan at rename-it.nl> wrote:
>> Unfortunately I do not know (yet) which client action produces these
>> log lines. "GET null null" seems not to be a sensible request in any
>> case.
>> Anyone seeing the same effect?
> Did this happen only after upgrade to 2.2.23 or is this a fresh install?

This effect has been observed with 2.2.18 (initial install) and after
upgrading to 2.2.23 as well.

> Can you make a dump of what messages are exchanged on using
> ngrep or wireshark?

I've captured some requests and they look like this (some parts
changed due to privacy concerns):

GET /solr/select?fl=uid,score&rows=439&sort=uid+asc&q={!lucene+q.op%3dAND}hdr:%3c56Fxxxx3A6.7080904 at domain.de%3e+OR+hdr:%3c664DCDxxxxx1A4FACD8B7922C495FEF at CZCHOWS1356.prg%5c-domain.com%3e+OR+hdr:%3c00cxxxxxde3$70ad7880$52
 ... (many many more OR hdrs)
&fq=%2Bbox:f696f93xxxxxx6e+%2Buser:user at domain.de HTTP/1.1

The total request size is 31708 bytes and it contains many (hundreds?)
of 'OR hdrs' (side note: I wonder which client action triggers these
kind of requests, maybe the user selected hundreds of mails for

I _think_ this is a problem of the URL length / max http header size.
(Debian Jessie) Tomcat7 very likely does not accept more than 32kb
data in a request.

I wonder if Dovecot should limit SOLR requests to a specific size and
deny long requests with an imap error (?)


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