Concurrent Manager Jobs Piling up due to Print Queues

1. Cups logs show below error. “0” bytes were unable to recognized by cups and hence threw below error thus creating stale printer queues at the OS level

D [24/Aug/2022:05:08:40 -0700] [Job 12114] Started filter pdftops (PID 18663)

D [24/Aug/2022:05:08:40 -0700] [Job 12114] Started filter pstops (PID 18664)

D [24/Aug/2022:05:08:40 -0700] [Job 12114] Command Line Error: Wrong page range given: the first page (1) can not be after the last page (0).

D [24/Aug/2022:05:08:40 -0700] [Job 12114] The print file is empty.

D [24/Aug/2022:05:08:40 -0700] [Job 12114] PID 18663 (pdftops) stopped with status 99!

D [24/Aug/2022:05:08:40 -0700] [Job 12114] PID 18664 (pstops) stopped with status 1!

2. For “2” days after we went live on EBS 12.2.10 on OCI as the printer queue jobs used to touch “500” number which included these stale stopped “Filter Failed” printer queues , applications stopped responding. The “MaxJobs” default settings(500) in cups configuration that made the application/concurrent requests to get stalled.

As root user: “lpstat -o | wc -l” showed 500

Quick Workaround(cancel -a was throwing forbidden error hence followed below commands as “root” user)

cd /var/spool/cups/;

ls -ltr |wc -l;

rm * ; systemctl

restart cups.service

3. Set the “MaxJobs” in cupds.conf . Please note setting “MaxJobs=0” makes it unlimited, if you wish to. By default, MAxJobs=500(if nothing is set)

grep -i max cupsd.conf

MaxLogSize 2000000000

MaxJobs 2000

4. Restarted Cups services

systemctl restart cups.service