Compaction observability is a notification and information system based on metrics about the health of the compaction process. A healthy compaction process is critical to query performance, availability, and uptime of your data warehouse. You learn how to use compaction observability to prevent serious problems from developing.
- Oldest initiated compaction passed threshold
- Large number of compaction failures
- More than one host is initiating compaction
- Warnings and errors that suggest next steps
- Charted metrics
- Hive logging
Compaction observability does not attempt to do root cause analysis (RCA) and does not attempt to fix the underlying problem. Compaction observability helps you quickly respond to symptoms of compaction problems. Factors unrelated to compaction per se can look like a compaction problem. For example, an underlying problem related to renewing a Kerberos ticket problem can surface as a compaction problem. Configuring kerberos to add authorization, changing the running user, or increasing the queue size might solve the problem. Compaction observability provides troubleshooting information.
Alerts are on by default in Cloudera Data Warehouse. By default, the compaction health data is collected by default. Alerts place no load on Hive. The data about compaction health is not stored for very long, and is not stored in Hive. The data is emitted from Hive, and a backend thread, which is configurable to run as often as you want, collects metrics in Prometheus.
See the Data Warehouse for Public Cloud release notes for information about how to pick up this feature if you do not see it.