Top RU
Top RU ranks SQL statements by their Request Unit (RU) consumption, helping you quickly identify which queries drive your RU usage. When you notice an unexpected RU spike in your TiDB Cloud Essential or TiDB Cloud Premium instance metrics, use Top RU to identify the responsible SQL statements and take targeted action.
Product plan comparison
Top RU capabilities vary by TiDB Cloud plan:
Open Top RU
- Log in to the TiDB Cloud console and navigate to your TiDB Cloud Essential or TiDB Cloud Premium instance.
- In the left navigation pane, click Monitoring > Top RU.
Analyze RU consumption by SQL
The Overview tab shows the top RU-consuming SQL statements across all database users for the selected time range.
Set filters
Use the filters at the top of the page to narrow down the data.
Time range: select a preset interval or a custom range.
Preset options: Last 15 min, 30 min, 1 hour, 2 hours, 6 hours, 12 hours, and 1 day.
For custom time ranges:
- The earliest available start date depends on your data retention: 30 days ago for TiDB Cloud Premium instances, and 7 days ago for TiDB Cloud Essential instances.
- The maximum window for a single query is 24 hours.
Top N: select how many SQL statements to display.
- TiDB Cloud Premium instance: 10 by default. Options: 5, 20, and 100.
- TiDB Cloud Essential instance: 10 by default. Options: 5 and 20.
Read the SQL list
The Top N SQL list shows the highest RU-consuming SQL statements for the selected filters:
View the RU trend
Hover over a SQL statement in the list to highlight its RU trend line in the trend chart. The chart shows RU consumption over the selected time range at one-minute intervals, helping you identify when a spike started and whether the spike is still ongoing.
Identify RU consumption by user
Rank by Users panel
The Overview tab includes a Top 3 DB Users (RU) panel that shows a ranked list of database users by their total RU consumption for the selected time range. Use this panel to determine whether a specific database user drives the RU spike.
Sliced by Users tab
To drill into a specific database user's SQL statements:
- Click the Sliced by Users tab.
- In the User filter, select the user you want to investigate. The filter displays up to 100 users and groups any additional users as Other users.
- The Top N SQL list and trend chart show only the selected user's queries.
Drill down into a SQL statement
Click a SQL statement in the Top N SQL list to open its detail panel.
Execution summary
Execution plans
Top RU displays information based on how many execution plans the SQL statement has and whether plan data is available.
Plans not available
When plan data is not available, Top RU does not show Plan digest, SQL RU Trend by Plan, or Execution Plan. The other fields remain visible.
Multiple plans
When the SQL has multiple execution plans, the panel displays a plan list first:
- Click an available plan to expand its full details.
- Click an unavailable plan to view its summary. Unavailable plans do not expand.
Typical workflow
Use the following workflow to investigate an RU spike:
- Notice an RU spike in your TiDB Cloud Essential or TiDB Cloud Premium instance metrics or a triggered alert.
- Go to Monitoring > Top RU, click the Overview tab, and select a time range covering the spike.
- Identify the SQL statements with the highest Total RU. Hover over each SQL statement to see its RU trend and identify when the spike started.
- Check the Rank by Users panel to see whether a specific user is driving the spike.
- If needed, go to the Sliced by Users tab, select the user, and focus on their top RU-consuming SQL statements.
- Click a SQL statement to open its detail panel. Review the execution plan to find optimization opportunities such as missing indexes.
- Use the Query Template ID to cross-reference Slow Query or SQL Statement for additional execution context.
- Apply optimizations, such as adding indexes, rewriting the SQL, or adjusting business logic.
- Return to the Top RU page and select a recent time range to confirm that RU consumption has decreased.
Limitations
- Not equivalent to billing RU: Top RU data is intended for near-real-time observability and might differ from the RU usage reported on your TiDB Cloud invoice. Do not use Top RU data for billing reconciliation or auditing.
- Top N aggregation: Only the highest RU-consuming SQL statements are displayed individually. SQL statements with lower RU consumption are aggregated into the Others category.
- Data freshness: Data is updated at minute-level granularity.
- Maximum query window: You can query up to 24 hours of data at a time.
FAQ
What is the difference between Top RU and Top SQL?
Top SQL ranks SQL statements by CPU time on a specific TiDB or TiKV node. It applies to TiDB Cloud Dedicated clusters.
Top RU ranks SQL statements by Request Unit (RU) consumption at the instance level and supports user-level breakdown. It applies to TiDB Cloud Premium instances and TiDB Cloud Essential instances.
Why is there no data in Top RU?
- Make sure the selected time range contains actual SQL workload.
- Refresh the page after running a workload for at least 1 minute.
- Check TiDB Cloud Release Notes to confirm that Top RU is available for your TiDB Cloud Essential or TiDB Cloud Premium instance version and region.
If the issue persists, contact TiDB Cloud Support.
Is Top RU the same as billing RU?
No. Top RU shows near-real-time RU statistics for diagnosing high-consumption SQL. For billing and cost management, refer to the billing RU in your TiDB Cloud billing console.
What is the difference between the RU usage in metrics and Top RU?
- The RU/s metric shows the 1-minute average RU rate (RU/s) at overall instance level.
- Top RU shows cumulative RU per SQL statement (RU/s × duration) over the selected time range, helping you identify which SQL statements consum the most resources in total.