BgwriterHibernate
The BgwriterHibernate wait event occurs when the background writer process has no work to do and enters a sleep state.
When Does Bgwriter Go Into Hibernate?
The background writer follows an adaptive algorithm that determines when to write and when to sleep. It wakes up periodically based on several configuration parameters:
- bgwriter_delay: The base delay between activity rounds.(default: 200ms)
- bgwriter_lru_maxpages: The maximum number of pages written per round.(default: 100)
- bgwriter_lru_multiplier: A multiplier that adjusts the number of pages to write based on recent demand.
Problem detection
you notice minimal BgwriterHibernate time on a normally quiet database
- A misconfigured autovacuum running aggressively
- A new ETL process loading data
- Inefficient queries causing excessive temporary file writes
- Insufficient shared_buffers causing frequent page eviction
- Storage performance issues