Understand wait events

Wait events show where your queries spend time waiting for resources instead of actively executing. Understanding wait events helps you identify resource contention, lock conflicts, and I/O bottlenecks that cause performance problems.

What are wait events

When a query executes, it alternates between:

Active execution: CPU is processing the query
Waiting: Query is blocked, waiting for a resource

Wait events capture what the query is waiting for. High wait times indicate that queries are spending significant time blocked rather than executing.

Why wait events matter

Wait events reveal performance problems that other metrics miss:

Problem	What metrics show	What wait events reveal
Lock contention	High query duration	Queries waiting for row/table locks
Disk I/O bottleneck	Slow queries	Queries waiting for disk reads
Connection pool exhaustion	Timeouts	Queries waiting for connections
Shared buffer contention	Memory pressure	Queries waiting for buffer access

Access wait events

To view wait events in Database Observability:

Navigate to Database Observability in Grafana Cloud.
In the Queries Overview, note the Wait Events Duration chart showing cumulative wait time.
Click a query to open its details.
Select the Wait Events tab for detailed analysis.

Overview dashboard wait events

The Queries Overview shows a bar chart of cumulative wait event duration by category. This gives you a quick view of where queries spend the most time waiting.

The overview chart groups individual wait event types into high-level categories for easier visualization:

PostgreSQL categories:

Category	Included wait event types
IO Wait	`IO`
Lock Wait	`Lock`, `LWLock`, `Activity`, `Extension`, `InjectionPoint`, `IPC`, `Timeout`, `BufferPin`. This broad category covers heavyweight locks, lightweight locks, and other synchronization or blocking waits.
Network Wait	`Client`

MySQL categories:

Category	Included wait event patterns
IO Wait	`wait/io/file/`, `wait/io/table/`
Lock Wait	`wait/lock/`, `wait/synch/`, `wait/io/lock/*`
Network Wait	`wait/io/socket/*`

Wait Events tab

The Wait Events tab shows a time series chart of wait events for a specific query. Use the dropdown to switch between four views:

Cumulative duration of wait events (by group): Stacked bars showing total wait time for each category (IO Wait, Lock Wait, Network Wait) over time. This is the default view.
Cumulative duration of wait events (breakdown): Stacked bars broken down by individual wait event name (for example, Lock:relation, IO:DataFileRead), giving a more granular picture.
Number of wait events: Count of wait events by category over time.
Wait events duration (by group): Average duration per event by category over time.

Use wait events for diagnosis

This workflow shows how to use wait events to narrow down the source of latency.

Workflow: Diagnose slow queries

Identify affected queries: In the Queries Overview, find queries with high wait event duration.
View wait events tab: Click the query and open the Wait Events tab.
Compare views: Use the dropdown to switch between cumulative duration, event count, and average duration to understand the wait pattern.
Drill into duration of wait events (breakdown): Switch to the breakdown view to see which specific wait events contribute the most time.
Take action: Apply fixes based on the dominant wait event type (refer to the tips below).

The following table lists common scenarios you may encounter:

Scenario	Wait pattern	Action
Database backup running	High I/O waits	Schedule backups during low-traffic periods
Large transaction	Lock waits increasing	Break into smaller transactions
Peak traffic	Multiple wait types elevated	Scale resources or optimize queries
New deployment	Lock waits on specific tables	Check for schema changes, new queries