===== How to reset CUPS Job ID =====

CUPS Job ID is a global integer that is incremented and assigned to each new print job. In this way a Job ID refers to a single job within the CUPS cache. CUPS ''NextJobId'' is held in ''/var/cache/cups/job.cache'' file.

RFC-2911 states that [[https://tools.ietf.org/html/rfc2911#section-4.3.2|job-id syntax]] is ''integer(1:MAX)''. The MAX is  [[https://tools.ietf.org/html/rfc2911#section-4.1.12|2**31 - 1]] == 2,147,483,647

Although this value is big enough to accommodate years of intensive printing, there might be times you want to reset the Job ID to zero for semantic reasons. For instance to mark the start of a new administrative period.

For a reset to zero, proceed as follows:

<code bash>
# Step 1: Make sure all pending jobs are end-of-state.
# Optionally, cancel all active jobs manually.
sudo cancel -a

# Step 2: Stop CUPS service.
sudo systemctl stop cups.service

# Step 3: Delete CUPS job history (c*) and job (p*) files .
sudo rm -f /var/spool/cups/c*
sudo rm -f /var/spool/cups/p*

# Step 4: Remove CUPS job.cache
sudo rm -f /var/cache/cups/job.cache

# Step 5: Start CUPS service.
sudo systemctl start cups.service
</code>

[[https://www.savapage.org/docs/manual/ch-install-config-cups-samba.html#ch-install-config-cups-job-id|SavaPage is prepared for a reset]] and handles it well, as it will certainly encounter a reset situation when moved to a new server.