[rt-users] Charts displaying only "sometimes" (GD problem?)

[Scotto Alberto]

Hi all,
I'm having problems with charts, both bar and pie charts. Little context: created new dashboard and new saved search (privately at group-level); trying to display a nice report in the form of a bar chart.
It happens that *under certain conditions* RT doesn't show any chart. Actually apache does not generate&return the image, as if I point Chrome to the link of the image [1], then it returns "Error 324 (net::ERR_EMPTY_RESPONSE) The server closed the connection without sending any data".
Up to now I found the following conditions (not excluding each other) that influence the displaying or not of a chart:
- type of chart (bar vs. pie)
- domain on X axis (queue/owner name/owner email address/etc.)
- language set in the user preferences
- user logged in

Eg. given chart A:
- if I login with user1 it shows, but with user2 it does not;
- given a user, if I select <bar,queue> it doesn't show, but <bar, CreatorNickname> works
- given a user and a certain pair <type_of_chart, domain_on_x_axis>, it works if I turn to English from user preferencies; it doesn't if I select Italian
- and so on...

I'm using RT 4.0.2 (never upgraded, it's a fresh install) on Red Hat Enterprise Linux AS release 4 (Nahant Update 2) with Apache/2.0.52, mod_perl ??, GD::Graph 1.44, glibc-2.3.4-2.13

CLUES:

1a. as soon as my browser asks for the image and RT doesn't generate it, RT prints in /opt/rt4/var/log/apache2.error the following 2 lines:
*** glibc detected *** free(): invalid pointer: 0x0dd16764 *** [Wed Nov 23 16:38:23 2011] [notice] child pid 10963 exit signal Aborted (6), possible coredump in /tmp/apache_core_dumps

1b. There's something more. Here's what apache's core dump says (resulting from the commands gdb /usr/sbin/httpd /tmp/apache_core_dumps/core.22613 + bt full):

#0  0x0096c7a2 in _dl_sysinfo_int80 () from /lib/ld-linux.so.2 No symbol table info available.
#1  0x006a07d5 in raise () from /lib/tls/libc.so.6 No symbol table info available.
#2  0x006a2149 in abort () from /lib/tls/libc.so.6 No symbol table info available.
#3  0x006d440a in __libc_message () from /lib/tls/libc.so.6 No symbol table info available.
#4  0x006dab3f in _int_free () from /lib/tls/libc.so.6 No symbol table info available.
#5  0x006daeba in free () from /lib/tls/libc.so.6 No symbol table info available.
#6  0x00cb2a57 in gdFree () from /usr/lib/libgd.so.2 No symbol table info available.
#7  0x00be9c36 in XS_GD__Image_png (my_perl=0x9b85a98, cv=0xa875550)
    at GD.xs:944
        data = (void *) 0xcec9a44
        size = 3545
        level = Variable "level" is not available.


2. after enabling logging by adding Set($LogToFile, "debug") to RT_Site_Config.pm, I noticed the following message in rt.log:
[Wed Nov 23 10:56:18 2011] [debug]: You've enabled GraphViz, but we couldn't load the module: Can't locate GraphViz.pm in @INC (@INC contains: [...] at /opt/rt4/sbin/../lib/RT/Config.pm line 542. (/opt/rt4/sbin/../lib/RT/Config.pm:543)

Clue #2 doesn't sound a good one to me, though. In fact I am trying to display charts not graphs! I read about showing relationships between tickets [2], but I'm not interested in that! Just wanted to extract some nice monthly reports as bar charts :) Then, I should not need to install Graphviz, should I?

Here's what I tried to do:
- clean mason cache (more than once)
- clean browser's cache (more than once)
- reinstalled GD::Image (with cpan 'force install')
- added Set($DisableGD, undef) to RT_Site_Config.pm, as well as Set($DisableGD, 0)

According to clue#1b it's GD that breaks everything ("at GD.xs:944"). Can you confirm my interpretation is correct? If so, maybe I could go for a reinstall of GD..?
Otherwise I could upgrade glibc, to what version?
Nevertheless, I *feel* like it's a cache problem, server-side. Not client-side because cleaning browser's cache doesn't help. I don't know if there exists a server-side cache in RT other than mason cache(which I already cleaned), however it's my own best explanation. In fact, if it were glibc or GD, I should never ever get any charts then! While "sometimes" I do!

Can anyone point me in the right direction?
Thank you very much in advance.

Alberto


[1] http://mydomain.com/Search/Chart?Class=RT%3A%3ATickets&Format=&Query=(%20Queue%20%3D%20'EstesaP'%20OR%20Queue%20%3D%20'EstesaI'%20)%20AND%20Created%20%3E%20'-30%20days'&Rows=10&SavedSearchId=RT%3A%3AGroup-126-SavedSearch-33&SearchType=Chart&ShowNavigation=0&hideable=1

[2] http://www.gossamer-threads.com/lists/rt/users/91783#91783


PS: If you need more examples/tests/information for debugging, please ask me.

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