Too many open files error

[rssh22]

• Version of collectd: collectd 5.10.0
• Operating system / distribution: Solaris 11
• Kernel version (if applicable): 0.5.11-0.175.3.35.0.6.0

Expected behavior

(Description of the behavior / output that you expected)
After launching the daemon the log file reports several lines like following:

Actual behavior

The csv files and log file aren't being written properly
(Description of the behavior / output that you observed)
The log file reports errors like the following for a short period of time just after the start. After that, the log file and the csv files (from csv_plugin) are not updated anymore:

[2021-03-09 14:46:38] csv plugin: fopen (/diag/collectd/csv/hcdsns-be-jee-r02a-id-c04-m1-n2/DataSource-opss-audit-viewDS/gauge-value-ResolvedAsCommittedTotalCount-2021-03-09) failed: Too many open files

Steps to reproduce

• step 1: Configure several writes for csv plugin
• step 2
• step 3

More info:

the process is running under a Solaris project:

collectd:107:Collectd Agent:::process.max-file-descriptor=(basic,16384,deny),(priv,32768,deny)

# plimit 4205
4205:   collectd -C /etc/opt/csw/collectd.conf -f
   resource              current         maximum
  time(seconds)         unlimited       unlimited
  file(blocks)          unlimited       unlimited
  data(kbytes)          unlimited       unlimited
  stack(kbytes)         8192            unlimited
  coredump(blocks)      unlimited       unlimited
  nofiles(descriptors)  16384           32768
  vmemory(kbytes)       unlimited       unlimited

# pfiles 4205 | tail -10
        SOCK_STREAM
        SO_SNDBUF(16384),SO_RCVBUF(5120)
        sockname: AF_UNIX 
        peer: collectd[4205] zone: global[0]
 573: S_IFSOCK mode:0666 dev:599,0 ino:62746 uid:0 gid:0 size:0
      O_RDWR|O_NONBLOCK
        SOCK_STREAM
        SO_SNDBUF(16384),SO_RCVBUF(5120)
        sockname: AF_UNIX 
        peer: collectd[4205] zone: global[0]

[eero-t]

Can you provide a list of open files? On Linux you would get that with ls -l /proc/$pidof collectd)/fd/, or using lsof tool.