Pega Diagnostic Center (PDC) gathers hourly usage information from monitored systems to create usage and system performance statistics that are divided by requestor type and by application. You can view these statistics on the Interactions and Interactions Per Node landing pages. If the agent that sends this information stops running, or if sending the usage tracking information is disabled in your application configuration, PDC does not display the usage and system performance information.

Symptoms

On the Interactions and Interactions Per Node landing pages, usage data is missing and a warning banner informs you either that an agent that feeds data to PDC is not running, or that the configuration setting for usage tracking is disabled.

The following warning banners are displayed:

• Warning. The Agents Push Hourly/Daily Log Usage Data agents that feed usage data to PDC is not running.
• Warning. The usage/usagetrackingenabled setting is disabled. Enable it to feed usage data to PDC.

Explanation

If you do not see data in the Distribution of healthy and slow interactions or Response time chart, check if there is data for the given Interaction chart (Web, Service, Background, or Async). If there is a 0, which is also valid data, it means that there were no interactions at this time, so there was no possibility to count the healthy and unhealthy interactions or response time. Undefined data means that PDC did not receive data.

This error might occur in the following circumstances:

• The agents that send hourly and daily log usage information are not running. For example, the agents were stopped or disabled manually or because of an exception.
• Usage tracking in your application is disabled.
• The agent responsible for sending data to PDC is not running. The cause can be the frequent restarts of nodes. You can check the Topology changes landing page to confirm if the nodes restart too often. If this is the case, this impacts the Push Hourly Log Usage Data By App Info agent. After a node restart is completed, the agent starts pushing the data again. Pega Support engineers can work with Pega Cloud and the operations team to stabilize the system by raising a cloud change request.
• Report timeouts for large data in pr_perf_stats table. The system reports timeouts for the definition PushLogUsageDataByAppToAES, which fetches data from data.pr_perf_stats, generating ReportTimeOut cases in PDC. This might cause missing data in PDC. GCS engineers can work with DBAs to tune the data.pr_perf_stats table. Additionally, you can reduce the number of days for which you retain pr_perf_stats data.
• PostgreSQL temporary file size exceeds temporary file limit. If TempFileLimit cases are observed for a particular tenant, GCS engineers can work with DBAs to increase the temp file limit.

Solution

Use the following approach to troubleshoot and resolve the usage tracking agent issues.

• If you see a warning about agents that are not running correctly, verify the status of the agents that send hourly and daily log usage information:
  1. In the PDC navigation pane, click Background Processing > Agents.
  2. In the Agent details section, search for the Push Daily Log Usage Info agent and for the Push Hourly Log Usage Data By App Info agent.
  3. Expand the agent, and then check whether it is running on one node.
  4. In the Agent details section, search for the Push Hourly Log Usage Data By App Info agent.
  5. Expand the agent, and then check whether it is running on one node.
  6. If at least one of the agents is not running correctly, start that agent.

If neither agent works, search for OPS0015, OPS0027, OPS0028 alerts with the additional application filter PegaAESRemote:8 and verify the root cause. If the agents are running, query pr_perf_stats. Agents search this table for records in the corresponding time frame (Hourly or Daily) and send data to PDC. If there is data that should be shown in the table, there might be a bug that needs further investigation. 

• If you see a warning about disabled usage tracking, check your application settings:
  1. In the PDC navigation pane, click System Resources > Nodes.
  2. In the Node details section, expand any of the util nodes, and then click Configuration setting info.
  3. Search for the usage/usagetrackingenabled setting, and then verify that the setting is set to True.
  4. If the setting is set to False, or if the setting does not exist in your application, contact Pega Support, and then request enabling usage tracking for your application.