Pollerd takes too much time scheduling polling when OpenNMS starts

On a customer installation, I noticed that OpenNMS takes too much time to start due to Pollerd.

I've never seen this before, but Pollerd takes around 15min to schedule polling for all the existing monitored services.

$ psql -U opennms -h localhost -W opennms
Password for user opennms: 
psql (9.4.8)
Type "help" for help.

opennms=> select count(*) from ifservices where status='A';
 count 
-------
 28641
(1 row)