Tuning CPU threads for PuppetDB is not always a simple case of add more and it will perform better. CPUs on the PuppetDB are in use for the PostgreSQL instance, the Message Queue (MQ) and web server provided by PuppetDB. If your server does have CPUs to spare, consider adding more CPU threads to process more messages at a time. If increasing the number of CPUs to PuppetDB is actually decreasing throughput, instead make sure more CPU resources are available for the MQ and web server. The setting for CPU threads is also found in puppet.conf, under the [command-processing] section.

On a Puppet Enterprise installation, we'll find this setting managed by Hiera:

puppet_enterprise::puppetdb::command_processing_threads: 2

In an open source installation, we will again use puppetlabs/puppetdb to manage this setting:

class profile::puppetdb {

  class {'puppetdb':
    command_threads => '2',
  }

}